U.S. patent application number 16/958225 was filed with the patent office on 2020-11-26 for method for producing thiocarboxamidine salt compound.
This patent application is currently assigned to KUMIAI CHEMICAL INDUSTRY CO., LTD.. The applicant listed for this patent is KUMIAI CHEMICAL INDUSTRY CO., LTD.. Invention is credited to Toshihiro Nagata.
Application Number | 20200369631 16/958225 |
Document ID | / |
Family ID | 1000005207288 |
Filed Date | 2020-11-26 |
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United States Patent
Application |
20200369631 |
Kind Code |
A1 |
Nagata; Toshihiro |
November 26, 2020 |
METHOD FOR PRODUCING THIOCARBOXAMIDINE SALT COMPOUND
Abstract
The present disclosure provides an industrially preferable,
economical, and environmentally friendly method for producing a
compound [C1] of formula (5), namely, a
(4,5-dihydroisoxazol-3-yl)thiocarboxamidine salt compound. The
present disclosure relates to a method wherein: a reaction
expressed by reaction formula [C2] is caused so as to produce a
compound of formula (4) by reacting a compound of formula (3) with
a halogenation agent in the presence of a nitrile solvent, and the
compound of formula (4) is subsequently reacted with an
isothiouronium-forming agent, thereby producing a compound of
formula (5). ##STR00001##
Inventors: |
Nagata; Toshihiro; (Tokyo,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KUMIAI CHEMICAL INDUSTRY CO., LTD. |
Tokyo |
|
JP |
|
|
Assignee: |
KUMIAI CHEMICAL INDUSTRY CO.,
LTD.
Tokyo
JP
|
Family ID: |
1000005207288 |
Appl. No.: |
16/958225 |
Filed: |
December 26, 2018 |
PCT Filed: |
December 26, 2018 |
PCT NO: |
PCT/JP2018/047744 |
371 Date: |
June 26, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C07D 261/04
20130101 |
International
Class: |
C07D 261/04 20060101
C07D261/04 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 27, 2017 |
JP |
2017-251100 |
Claims
1. A process for producing a compound of the formula (5):
##STR00018## wherein R.sup.1 and R.sup.2 are each independently
optionally substituted (C1-C6)alkyl; optionally substituted
(C3-C6)cycloalkyl; optionally substituted (C2-C6)alkenyl;
optionally substituted (C2-C6)alkynyl; optionally substituted
(C1-C6)alkoxy; or optionally substituted phenyl; or R.sup.1 and
R.sup.2, together with the carbon atom to which they are attached
form a 4- to 12-membered carbocyclic ring, wherein the formed ring
is optionally substituted, X is a halogen, which comprises the
following steps (C) and (D): step (C): reacting a compound of the
formula (3) with a halogenating agent in the presence of a nitrile
solvent and a water solvent to produce a compound of the formula
(4), ##STR00019## wherein R.sup.1, R.sup.2 and X are as defined
above, step (D): reacting the compound of the formula (4) with an
isothiouronium-forming agent to produce the compound of the formula
(5), ##STR00020## wherein R.sup.1, R.sup.2 and X are as defined
above.
2. (canceled)
3. The process according to claim 1, wherein the amount of the
nitrile solvent to be used in the reaction of the step (C) is 0.4
to 2.0 L based on 1 mol of the compound of the formula (3).
4. The process according to claim 1, wherein the amount of the
nitrile solvent to be used in the reaction of the step (C) is 0.5
to 1.5 L based on 1 mol of the compound of the formula (3).
5. The process according to claim 1, wherein the amount of the
nitrile solvent to be used in the reaction of the step (C) is 0.5
to 1.0 L based on 1 mol of the compound of the formula (3).
6. The process according to claim 1, wherein the amount of the
water solvent to be used in the reaction of the step (C) is 0.10 to
0.40 L based on 1 mol of the compound of the formula (3).
7. The process according to claim 1, wherein the amount of the
water solvent to be used in the reaction of the step (C) is 0.15 to
0.33 L based on 1 mol of the compound of the formula (3).
8. The process according to claim 1, wherein the amount of water to
be used in the reaction of the step (C) is 10 vol % or more and 42
vol % or less of the amount of the mixed solvent of the nitrile
solvent and water.
9. The process according to claim 1, wherein the amount of water to
be used in the reaction of the step (C) is 10 vol % or more and 40
vol % or less of the amount of the mixed solvent of the nitrile
solvent and water.
10. The process according to claim 1, wherein the amount of water
to be used in the reaction of the step (C) is 20 vol % or more and
40 vol % or less of the amount of the mixed solvent of the nitrile
solvent and water.
11. The process according to claim 1, wherein the reaction of the
step (D) is performed in the presence of a nitrile solvent.
12. The process according to claim 1, wherein the reaction of the
step (D) is performed in the presence of a nitrile solvent and a
water solvent.
13. The process according to claim 11, wherein the amount of the
nitrile solvent to be used in the reaction of the step (D) is 0.4
to 2.0 L based on 1 mol of the compound of the formula (3).
14. The process according to claim 11, wherein the amount of the
nitrile solvent to be used in the reaction of the step (D) is 0.5
to 1.5 L based on 1 mol of the compound of the formula (3).
15. The process according to claim 11, wherein the amount of the
nitrile solvent to be used in the reaction of the step (D) is 0.5
to 1.0 L based on 1 mol of the compound of the formula (3).
16. The process according to claim 12, wherein the amount of the
water solvent to be used in the reaction of the step (D) is 0.10 to
0.40 L based on 1 mol of the compound of the formula (3).
17. The process according to claim 12, wherein the amount of the
water solvent to be used in the reaction of the step (D) is 0.15 to
0.33 L based on 1 mol of the compound of the formula (3).
18. The process according to claim 12, wherein the amount of water
to be used in the reaction of the step (D) is 10 vol % or more and
42 vol % or less of the amount of the mixed solvent of the nitrile
solvent and water.
19. The process according to claim 12, wherein the amount of water
to be used in the reaction of the step (D) is 10 vol % or more and
40 vol % or less of the amount of the mixed solvent of the nitrile
solvent and water.
20. The process according to claim 12, wherein the amount of water
to be used in the reaction of the step (D) is 20 vol % or more and
40 vol % or less of the amount of the mixed solvent of the nitrile
solvent and water.
21. The process according to claim 1, wherein the reaction of the
step (C) and the reaction of the step (D) are performed in the same
solvent.
22. The process according to claim 1, wherein the step (C) and the
step (D) are performed in the same reaction vessel.
23. The process according to claim 1, wherein the nitrile solvent
is acetonitrile.
24. The process according to claim 1, wherein the halogenating
agent is chlorine.
25. The process according to claim 1, wherein the
isothiouronium-forming agent is thiourea.
26. The process according to claim 1, wherein R.sup.1 and R.sup.2
are methyl and X is a chlorine atom.
Description
TECHNICAL FIELD
[0001] The present invention relates to a process for producing a
compound of the formula (5):
##STR00002##
[0002] wherein R.sup.1, R.sup.2 and X are as described below, i.e.,
a (4,5-dihydroisoxazol-3-yl)thiocarboxamidine salt compound.
BACKGROUND ART
[0003] (4,5-Dihydroisoxazol-3-yl)thiocarboxamidine salt compounds
of the formula (5) are useful as intermediates for the production
of pharmaceuticals, agricultural chemicals, etc. WO 2002/062770
(Patent Document 1) discloses useful herbicides. Among them,
pyroxasulfone is well known as a herbicide having excellent
herbicidal activity. Furthermore, JP 2013-512201 A (Patent Document
2) and WO 2006/068092 (Patent Document 3) disclose that the
compounds of the formula (5) are important intermediates for the
herbicides described in Patent Document 1.
[0004] JP 2013-512201 A (Patent Document 2) discloses a process for
producing (4,5-dihydroisoxazol-3-yl)thiocarboxamidine salt
compounds. In the specific and most preferable process described in
Patent Document 2, a 3-unsubstituted-4,5-dihydroisoxazole compound
is reacted with a halogenating agent (e.g., a chlorinating agent)
with use of tert-butanol as a reaction solvent to produce a
3-halogenated-4,5-dihydroisoxazole compound (e.g.,
3-chloro-4,5-dihydroisoxazole compound), which is then reacted with
thiourea in the same reaction solvent to obtain a target
(4,5-dihydroisoxazol-3-yl)thiocarboxamidine salt compound (for
example, see Example 6 of Patent Document 2).
[0005] WO 2006/068092 (Patent Document 3) discloses a process for
producing a (4,5-dihydroisoxazol-3-yl)thiocarboxamidine salt
compound by reacting a 3-halogenated-4,5-dihydroisoxazole compound
with thiourea in the presence of an acid. In particular, Patent
Document 3 describes that an acid is effective. That is, according
to Patent Document 3, an acid is essential for the reaction of a
3-halogenated-4,5-dihydroisoxazole compound with thiourea. The acid
may be in a catalytic amount, but it is understood that a certain
amount of acid is required to obtain a high yield in a short
reaction time (see, for example, Examples 4 and 5 of Patent
Document 3).
[0006] JP 2013-512201 A (Patent Document 2) describes that the
process of Patent Document 2 does not require additional addition
of an acid (see Patent Document 2, paragraph 0064). In the process
of Patent Document 2, the 3-chloro-4,5-dihydroisoxazole compound is
produced by reacting the 3-unsubstituted-4,5-dihydroisoxazole
compound with chlorine, and then the reaction with thiourea is
performed directly without performing purification in the same
reaction vessel, that is, in a one-pot process (see, for example,
Example 6 and paragraph 0060 of Patent Document 2). After the
chlorination, if the reaction with thiourea is performed in a
one-pot process without performing purification, the hydrogen
chloride generated by the chlorination remains in the reaction
system without being removed, and is presumed to serve as an acid
catalyst in the reaction with thiourea. Therefore, additional
addition of an acid before the reaction with thiourea is not
necessary in the process of Patent Document 2.
##STR00003##
[0007] The process of Patent Document 2 does not require the
additional addition of an acid, but an acid itself is essential
also in the reaction with thiourea in the process of Patent
Document 2, and as the acid, an acid generated by chlorination in
the previous step and remaining is understood to be utilized (see
the above figure).
[0008] However, in Example 6 of Patent Document 2, a long reaction
time of 60 hours or more at a reaction temperature of 20.degree. C.
is required to complete the reaction. From the viewpoint of
economic efficiency, etc., it is generally preferable that the
reaction be completed at around ambient temperature and in a short
time, but it is understood that the process of Patent Document 2
requires a long reaction time at around ambient temperature. Long
reaction times are not economical and are industrially undesirable.
Further, the yield achieved in Example 6 of Patent Document 2 is
only 59%, and the process of Patent Document 2 is not economical in
terms of yield and is not industrially preferable.
CITATION LIST
Patent Document
[0009] Patent Document 1: WO 2002/062770 A1 [0010] Patent Document
2: JP 2013-512201 A [0011] Patent Document 3: WO 2006/068092 A1
SUMMARY OF INVENTION
Technical Problem
[0012] There has been desired an industrially preferable process
for producing a compound of the above formula (5), i.e., a target
(4,5-dihydroisoxazol-3-yl)thiocarboxamidine salt compound, the
process being capable of solving the above-described one or more
disadvantages or problems in the prior art. Therefore, an object of
the present disclosure is to provide a process for producing the
target compound, which process is industrially preferable,
economical, and environmentally friendly. A specific object of the
present disclosure is to provide a process capable of producing the
target compound in a short time and with a high yield. Another
specific object of the present disclosure is to provide a process
capable of producing the target compound by a simple operation
without requiring a special equipment.
Solution to Problem
[0013] In view of the circumstances as described above, the present
inventor has earnestly studied a process for producing a compound
of the formula (5). As a result, the present inventor unexpectedly
found that the above problems can be solved by providing the
following processes for producing the compound of the formula (5).
The present inventor has accomplished the present invention based
on this finding.
[0014] That is, in one embodiment, the present invention is as
follows. [0015] [I-1] A process for producing a compound of the
formula (5):
##STR00004##
[0016] wherein R.sup.1 and R.sup.2 are each independently
optionally substituted (C1-C6)alkyl; optionally substituted
(C3-C6)cycloalkyl; optionally substituted (C2-C6)alkenyl;
optionally substituted (C2-C6)alkynyl; optionally substituted
(C1-C6)alkoxy; or optionally substituted phenyl; or
[0017] R.sup.1 and R.sup.2, together with the carbon atom to which
they are attached form a 4- to 12-membered carbocyclic ring,
wherein the formed ring is optionally substituted,
[0018] X is a halogen,
[0019] which comprises the following steps (C) and (D):
[0020] step (C): reacting a compound of the formula (3) with a
halogenating agent in the presence of a nitrile solvent to produce
a compound of the formula (4),
##STR00005##
[0021] wherein R.sup.1, R.sup.2 and X are as defined above,
[0022] step (D): reacting the compound of the formula (4) with an
isothiouronium-forming agent to produce the compound of the formula
(5),
##STR00006##
[0023] wherein R.sup.1, R.sup.2 and X are as defined above. [0024]
[I-2] The process according to [I-1], wherein the reaction of the
step (C) is performed in the presence of a nitrile solvent and a
water solvent. [0025] [I-3] The process according to [I-1] or
[I-2], wherein the amount of the nitrile solvent to be used in the
reaction of the step (C) is 0.4 to 2.0 L based on 1 mol of the
compound of the formula (3). [0026] [I-4] The process according to
[I-1] or [I-2], wherein the amount of the nitrile solvent to be
used in the reaction of the step (C) is 0.5 to 1.5 L based on 1 mol
of the compound of the formula (3). [0027] [I-5] The process
according to [I-1] or [I-2], wherein the amount of the nitrile
solvent to be used in the reaction of the step (C) is 0.5 to 1.0 L
based on 1 mol of the compound of the formula (3). [0028] [I-6] The
process according to any one of [I-2] to [I-5], wherein the amount
of the water solvent to be used in the reaction of the step (C) is
0.10 to 0.40 L based on 1 mol of the compound of the formula (3).
[0029] [I-7] The process according to any one of [I-2] to [I-5],
wherein the amount of the water solvent to be used in the reaction
of the step (C) is 0.15 to 0.33 L based on 1 mol of the compound of
the formula (3). [0030] [I-8] The process according to any one of
[I-2] to [I-7], wherein the amount of water to be used in the
reaction of the step (C) is 10 vol % or more and 42 vol % or less
of the amount of the mixed solvent of the nitrile solvent and
water. [0031] [I-9] The process according to any one of [I-2] to
[I-7], wherein the amount of water to be used in the reaction of
the step (C) is 10 vol % or more and 40 vol % or less of the amount
of the mixed solvent of the nitrile solvent and water. [0032]
[I-10] The process according to any one of [I-2] to [I-7], wherein
the amount of water to be used in the reaction of the step (C) is
20 vol % or more and 40 vol % or less of the amount of the mixed
solvent of the nitrile solvent and water. [0033] [I-11] The process
according to any one of [I-1] to [I-10], wherein the reaction of
the step (D) is performed in the presence of a nitrile solvent.
[0034] [I-12] The process according to any one of [I-1] to [I-10],
wherein the reaction of the step (D) is performed in the presence
of a nitrile solvent and a water solvent. [0035] [I-13] The process
according to [I-11] or [I-12], wherein the amount of the nitrile
solvent to be used in the reaction of the step (D) is 0.4 to 2.0 L
based on 1 mol of the compound of the formula (3). [0036] [I-14]
The process according to [I-11] or [I-12], wherein the amount of
the nitrile solvent to be used in the reaction of the step (D) is
0.5 to 1.5 L based on 1 mol of the compound of the formula (3).
[0037] [I-15] The process according to [I-11] or [I-12], wherein
the amount of the nitrile solvent to be used in the reaction of the
step (D) is 0.5 to 1.0 L based on 1 mol of the compound of the
formula (3). [0038] [I-16] The process according to any one of
[I-12] to [I-15], wherein the amount of the water solvent to be
used in the reaction of the step (D) is 0.10 to 0.40 L based on 1
mol of the compound of the formula (3). [0039] [I-17] The process
according to any one of [I-12] to [I-15], wherein the amount of the
water solvent to be used in the reaction of the step (D) is 0.15 to
0.33 L based on 1 mol of the compound of the formula (3). [0040]
[I-18] The process according to any one of [I-12] to [I-17],
wherein the amount of water to be used in the reaction of the step
(D) is 10 vol % or more and 42 vol % or less of the amount of the
mixed solvent of the nitrile solvent and water. [0041] [I-19] The
process according to any one of [I-12] to [I-17], wherein the
amount of water to be used in the reaction of the step (D) is 10
vol % or more and 40 vol % or less of the amount of the mixed
solvent of the nitrile solvent and water. [0042] [I-20] The process
according to any one of [I-12] to [I-17], wherein the amount of
water to be used in the reaction of the step (D) is 20 vol % or
more and 40 vol % or less of the amount of the mixed solvent of the
nitrile solvent and water. [0043] [I-21] The process according to
any one of [I-1] to [I-20], wherein the reaction of the step (C)
and the reaction of the step (D) are performed in the same solvent.
[0044] [I-22] The process according to any one of [I-1] to [I-21],
wherein the step (C) and the step (D) are performed in the same
reaction vessel. [0045] [I-23] The process according to any one of
[I-1] to [I-22], wherein the nitrile solvent is acetonitrile.
[0046] [I-24] The process according to any one of [I-1] to [I-23],
wherein the halogenating agent is chlorine. [0047] [I-25] The
process according to any one of [I-1] to [I-24], wherein the
isothiouronium-forming agent is thiourea. [0048] [I-26] The process
according to any one of [I-1] to [I-25], wherein R.sup.1 and
R.sup.2 are methyl and X is a chlorine atom. [0049] [I-27] The
process according to any one of [I-1] to [I-26], wherein the
reaction of the step (C) is performed at -5.degree. C. to
50.degree. C. [0050] [I-28] The process according to any one of
[I-1] to [I-26], wherein the reaction of the step (C) is performed
at 0.degree. C. to 30.degree. C. [0051] [I-29] The process
according to any one of [I-1] to [I-28], wherein the reaction of
the step (D) is performed at 0.degree. C. to 60.degree. C. [0052]
[I-30] The process according to any one of [I-1] to [I-28], wherein
the reaction of the step (D) is performed at 15.degree. C. to
40.degree. C.
[0053] In another embodiment, the present invention is as follows.
[0054] [II-1] A process for producing a compound of the formula
(5):
##STR00007##
[0055] wherein R.sup.1 and R.sup.2 are each independently
optionally substituted (C1-C6)alkyl; optionally substituted
(C3-C6)cycloalkyl; optionally substituted (C2-C6)alkenyl;
optionally substituted (C2-C6)alkynyl; optionally substituted
(C1-C6)alkoxy; or optionally substituted phenyl; or
[0056] R.sup.1 and R.sup.2, together with the carbon atom to which
they are attached form a 4- to 12-membered carbocyclic ring,
wherein the formed ring is optionally substituted, and
[0057] X is a halogen,
[0058] which comprises the following steps (C) and (D):
[0059] step (C): reacting a compound of the formula (3) with a
halogenating agent in the presence of a nitrile solvent and a water
solvent to produce a compound of the formula (4),
##STR00008##
[0060] wherein R.sup.1, R.sup.2 and X are as defined above,
[0061] step (D): reacting the compound of the formula (4) with an
isothiouronium-forming agent to produce the compound of the formula
(5),
##STR00009##
[0062] wherein R.sup.1, R.sup.2 and X are as defined above. [0063]
[II-2] The process according to [II-1], wherein the amount of the
nitrile solvent to be used in the reaction of the step (C) is 0.1
to 5.0 L based on 1 mol of the compound of the formula (3). [0064]
[II-3] The process according to [II-1], wherein the amount of the
nitrile solvent to be used in the reaction of the step (C) is 0.3
to 3.0 L based on 1 mol of the compound of the formula (3). [0065]
[II-4] The process according to [II-1], wherein the amount of the
nitrile solvent to be used in the reaction of the step (C) is 0.4
to 2.0 L based on 1 mol of the compound of the formula (3). [0066]
[II-5] The process according to [II-1], wherein the amount of the
nitrile solvent to be used in the reaction of the step (C) is 0.5
to 2.0 L based on 1 mol of the compound of the formula (3). [0067]
[II-6] The process according to [II-1], wherein the amount of the
nitrile solvent to be used in the reaction of the step (C) is 0.4
to 1.5 L based on 1 mol of the compound of the formula (3). [0068]
[II-7] The process according to [II-1], wherein the amount of the
nitrile solvent to be used in the reaction of the step (C) is 0.5
to 1.5 L based on 1 mol of the compound of the formula (3). [0069]
[II-8] The process according to [II-1], wherein the amount of the
nitrile solvent to be used in the reaction of the step (C) is 0.5
to 1.0 L based on 1 mol of the compound of the formula (3). [0070]
[II-9] The process according to any one of [II-1] to [II-8],
wherein the amount of the water solvent to be used in the reaction
of the step (C) is 0.10 to 1.00 L based on 1 mol of the compound of
the formula (3). [0071] [II-10] The process according to any one of
[II-1] to [II-8], wherein the amount of the water solvent to be
used in the reaction of the step (C) is 0.10 to 0.40 L based on 1
mol of the compound of the formula (3). [0072] [II-11] The process
according to any one of [II-1] to [II-8], wherein the amount of the
water solvent to be used in the reaction of the step (C) is 0.13 to
0.40 L based on 1 mol of the compound of the formula (3). [0073]
[II-12] The process according to any one of [II-1] to [II-8],
wherein the amount of the water solvent to be used in the reaction
of the step (C) is 0.15 to 0.40 L based on 1 mol of the compound of
the formula (3). [0074] [II-13] The process according to any one of
[II-1] to [II-8], wherein the amount of the water solvent used in
the reaction of the step (C) is 0.15 to 0.33 L based on 1 mol of
the compound of the formula (3). [0075] [II-14] The process
according to any one of [II-1] to [II-8], wherein the amount of the
water solvent to be used in the reaction of the step (C) is 0.13 to
0.35 L based on 1 mol of the compound of the formula (3). [0076]
[II-15] The process according to any one of [II-1] to [II-14],
wherein the amount of water to be used in the reaction of the step
(C) is 5 vol % or more and 50 vol % or less of the amount of the
mixed solvent of the nitrile solvent and water. [0077] [II-16] The
process according to any one of [II-1] to [II-14], wherein the
amount of water to be used in the reaction of the step (C) is 10
vol % or more and 42 vol % or less of the amount of the mixed
solvent of the nitrile solvent and water. [0078] [II-17] The
process according to any one of [II-1] to [II-14], wherein the
amount of water to be used in the reaction of the step (C) is 10
vol % or more and 40 vol % or less of the amount of the mixed
solvent of the nitrile solvent and water. [0079] [II-18] The
process according to any one of [II-1] to [II-14], wherein the
amount of water to be used in the reaction of the step (C) is 20
vol % or more and 40 vol % or less of the amount of the mixed
solvent of the nitrile solvent and water. [0080] [II-19] The
process according to any one of [II-1] to [II-14], wherein the
amount of water to be used in the reaction of the step (C) is 20
vol % or more and 30 vol % or less of the amount of the mixed
solvent of the nitrile solvent and water. [0081] [II-20] The
process according to any one of [II-1] to [II-14], wherein the
amount of water to be used in the reaction of the step (C) is 10
vol % or more and 30 vol % or less of the amount of the mixed
solvent of the nitrile solvent and water. [0082] [II-21] The
process according to any one of [II-1] to [II-20], wherein the
reaction of the step (D) is performed in the presence of a nitrile
solvent and a water solvent. [0083] [II-22] The process according
to [II-21], wherein the amount of the nitrile solvent to be used in
the reaction of the step (D) is 0.1 to 5.0 L based on 1 mol of the
compound of the formula (3). [0084] [II-23] The process according
to [II-21], wherein the amount of the nitrile solvent to be used in
the reaction of the step (D) is 0.3 to 3.0 L based on 1 mol of the
compound of the formula (3). [0085] [II-24] The process according
to [II-21], wherein the amount of the nitrile solvent to be used in
the reaction of the step (D) is 0.4 to 2.0 L based on 1 mol of the
compound of the formula (3). [0086] [II-25] The process according
to [II-21], wherein the amount of the nitrile solvent to be used in
the reaction of the step (D) is 0.5 to 2.0 L based on 1 mol of the
compound of the formula (3). [0087] [II-26] The process according
to [II-21], wherein the amount of the nitrile solvent to be used in
the reaction of the step (D) is 0.4 to 1.5 L based on 1 mol of the
compound of the formula (3). [0088] [II-27] The process according
to [II-21], wherein the amount of the nitrile solvent to be used in
the reaction of the step (D) is 0.5 to 1.5 L based on 1 mol of the
compound of the formula (3). [0089] [II-28] The process according
to [II-21], wherein the amount of the nitrile solvent to be used in
the reaction of the step (D) is 0.5 to 1.0 L based on 1 mol of the
compound of the formula (3). [0090] [II-29] The process according
to any one of [II-21] to [II-28], wherein the amount of the water
solvent to be used in the reaction of the step (D) is 0.10 to 1.00
L based on 1 mol of the compound of the formula (3). [0091] [II-30]
The process according to any one of [II-21] to [II-28], wherein the
amount of the water solvent to be used in the reaction of the step
(D) is 0.10 to 0.40 L based on 1 mol of the compound of the formula
(3). [0092] [II-31] The process according to any one of [II-21] to
[II-28], wherein the amount of the water solvent to be used in the
reaction of the step (D) is 0.13 to 0.40 L based on 1 mol of the
compound of the formula (3). [0093] [II-32] The process according
to any one of [II-21] to [II-28], wherein the amount of the water
solvent to be used in the reaction of the step (D) is 0.15 to 0.40
L based on 1 mol of the compound of the formula (3). [0094] [II-33]
The process according to any one of [II-21] to [II-28], wherein the
amount of the water solvent to be used in the reaction of the step
(D) is 0.15 to 0.33 L based on 1 mol of the compound of the formula
(3). [0095] [II-34] The process according to any one of [II-21] to
[II-28], wherein the amount of the water solvent to be used in the
reaction of the step (D) is 0.13 to 0.35 L based on 1 mol of the
compound of the formula (3). [0096] [II-35] The process according
to any one of [II-21] to [II-34], wherein the amount of water to be
used in the reaction of the step (D) is 5 vol % or more and 50 vol
% or less of the amount of the mixed solvent of the nitrile solvent
and water. [0097] [II-36] The process according to any one of
[II-21] to [II-34], wherein the amount of water to be used in the
reaction of the step (D) is 10 vol % or more and 42 vol % or less
of the amount of the mixed solvent of the nitrile solvent and
water. [0098] [II-37] The process according to any one of [II-21]
to [II-34], wherein the amount of water to be used in the reaction
of the step (D) is 10 vol % or more and 40 vol % or less of the
amount of the mixed solvent of the nitrile solvent and water.
[0099] [II-38] The process according to any one of [II-21] to
[II-34], wherein the amount of water to be used in the reaction of
the step (D) is 20 vol % or more and 40 vol % or less of the amount
of the mixed solvent of the nitrile solvent and water. [0100]
[II-39] The process according to any one of [II-21] to [II-34],
wherein the amount of water to be used in the reaction of the step
(D) is 20 vol % or more and 30 vol % or less of the amount of the
mixed solvent of the nitrile solvent and water. [0101] [II-40] The
process according to any one of [II-21] to [II-34], wherein the
amount of water to be used in the reaction of the step (D) is 10
vol % or more and 30 vol % or less of the amount of the mixed
solvent of the nitrile solvent and water. [0102] [II-41] The
process according to any one of [II-1] to [II-40], wherein the
reaction of the step (C) and the reaction of the step (D) are
performed in the same solvent. [0103] [II-42] The process according
to any one of [II-1] to [II-41], wherein the step (C) and the step
(D) are performed in the same reaction vessel. [0104] [II-43] The
process according to any one of [II-1] to [II-42], wherein the
nitrile solvent is acetonitrile. [0105] [II-44] The process
according to any one of [II-1] to [II-43], wherein the halogenating
agent is a chlorinating agent or a brominating agent. [0106]
[II-45] The process according to any one of [II-1] to [II-43],
wherein the halogenating agent is chlorine or bromine. [0107]
[II-46] The process according to [II-44] or [II-45], wherein
R.sup.1 and R.sup.2 are each independently (C1-C4)alkyl and X is a
chlorine atom or a bromine atom. [0108] [II-47] The process
according to [II-44] or [II-45], wherein R.sup.1 and R.sup.2 are
methyl and X is a chlorine atom or a bromine atom. [0109] [II-48]
The process according to any one of [II-1] to [II-43], wherein the
halogenating agent is a chlorinating agent. [0110] [II-49] The
process according to any one of [II-1] to [II-43], wherein the
halogenating agent is chlorine. [0111] [II-50] The process
according to [II-48] or [II-49], wherein R.sup.1 and R.sup.2 are
each independently (C1-C4)alkyl and X is a chlorine atom. [0112]
[II-51] The process according to [II-48] or [II-49], wherein
R.sup.1 and R.sup.2 are methyl and X is a chlorine atom. [0113]
[II-52] The process according to any one of [II-1] to [II-51],
wherein the isothiouronium-forming agent is thiourea. [0114]
[II-53] The process according to any one of [II-1] to [II-52],
wherein the reaction of the step (C) is performed at -5.degree. C.
to 50.degree. C. [0115] [II-54] The process according to any one of
[II-1] to [II-52], wherein the reaction of the step (C) is
performed at 0.degree. C. to 30.degree. C. [0116] [II-55] The
process according to any one of [II-1] to [II-54], wherein the
reaction of the step (D) is performed at 0.degree. C. to 60.degree.
C. [0117] [II-56] The process according to any one of [II-1] to
[II-54], wherein the reaction of the step (D) is performed at
15.degree. C. to 40.degree. C.
Advantageous Effects of Invention
[0118] The present disclosure provides a novel process for
producing the compound of the formula (5). According to the present
disclosure, there is provided a process for producing the compound
of the formula (5), which can overcome one or more of the
disadvantages or problems of the prior art described above.
[0119] According to the present disclosure, the target compound can
be produced in a short time and with a high yield. According to the
present disclosure, it is possible to produce the target compound
by a simple operation without requiring a special equipment.
[0120] Therefore, the process of the present disclosure is
industrially preferable, economical, and environmentally friendly,
and has high industrial utility value.
DESCRIPTION OF EMBODIMENTS
[0121] The present invention will be described in detail below.
[0122] The terms and symbols used herein will be explained
below.
[0123] Examples of the halogen atom include fluorine atom, chlorine
atom, bromine atom and iodine atom.
[0124] (Ca-Cb) means that the number of carbon atoms is a to b. For
example, "(C1-C4)" in "(C1-C4)alkyl" means that the number of the
carbon atoms in the alkyl is 1 to 4.
[0125] Herein, it is to be understood that generic terms such as
"alkyl" include both the straight chain and branched chain such as
butyl and tert-butyl. However, when a specific term such as "butyl"
is used, it is specific for "normal butyl", i.e., "n-butyl". In
other words, the specific term "butyl" refers to "normal butyl",
which is a straight chain. Branched chain isomers such as
"tert-butyl" are referred to specifically when intended.
[0126] The prefixes "n-", "s-" and "sec-", "i-", "t-" and "tert-",
"neo-", "c-" and "cyc-", "o-", "m-", and "p-" have their common
meanings as follows: normal, secondary ("s-" and "sec-"), iso,
tertiary ("t-" and "tert-"), neo, cyclo ("c-" and "cyc-"), ortho,
meta, and para.
[0127] Herein, the following abbreviations may be used:
[0128] "Me" means methyl.
[0129] "Et" means ethyl.
[0130] "Pr", "n-Pr" and "Pr-n" mean propyl (i.e., normal
propyl).
[0131] "i-Pr" and "Pr-i" mean isopropyl.
[0132] "Bu", "n-Bu" and "Bu-n" mean butyl (i.e., normal butyl).
[0133] "s-Bu" and "Bu-s" mean sec-butyl.
[0134] "i-Bu" and "Bu-i" mean isobutyl.
[0135] "t-Bu" and "Bu-t" mean tert-butyl.
[0136] "Pen", "n-Pen" and "Pen-n" mean pentyl (i.e., normal
pentyl).
[0137] "Hex", "n-Hex" and "Hex-n" mean hexyl (i.e., normal
hexyl).
[0138] "Dec", "n-Dec" and "Dec-n" mean decyl (i.e., normal
decyl).
[0139] "c-Pr" and "Pr-c" mean cyclopropyl.
[0140] "c-Bu" and "Bu-c" mean cyclobutyl.
[0141] "c-Pen" and "Pen-c" mean cyclopentyl.
[0142] "c-Hex" and "Hex-c" mean cyclohexyl.
[0143] "Ph" means phenyl.
[0144] "Bn" means benzyl.
[0145] "Ms" means methylsulfonyl (CH.sub.3SO.sub.2--).
[0146] "Ts" means tosyl (4-CH.sub.3--C.sub.6H.sub.4SO.sub.2--).
[0147] "Tf" means trifluoromethylsulfonyl (CF.sub.3SO.sub.2--).
[0148] "Ac" means acetyl (CH.sub.3CO--).
[0149] The (C1-C6)alkyl means a straight or branched alkyl having 1
to 6 carbon atoms. Examples of the (C1-C6)alkyl include, but are
not limited to, methyl, ethyl, propyl, isopropyl, butyl, sec-butyl,
isobutyl, tert-butyl, pentyl, isopentyl, neopentyl, and hexyl.
[0150] The (C1-C4)alkyl means a straight or branched alkyl having 1
to 4 carbon atoms. Examples of the (C1-C4)alkyl are appropriate
examples of the above-mentioned examples of the (C1-C6)alkyl.
[0151] The (C1-C6)haloalkyl means a straight or branched alkyl
having 1 to 6 carbon atoms which is substituted with 1 to 13 same
or different halogen atoms, wherein the halogen atoms have the same
meaning as defined above. Examples of the (C1-C6)haloalkyl include,
but are not limited to, fluoromethyl, difluoromethyl,
trifluoromethyl, chlorodifluoromethyl, 2-fluoroethyl,
2-chloroethyl, 2,2,2-trifluoroethyl, pentafluoroethyl,
3-fluoropropyl, 3-chloropropyl, 2,2,3,3,3-pentafluoropropyl,
2,2,2-trifluoro-1-trifluoromethylethyl, heptafluoropropyl,
1,2,2,2-tetrafluoro-1-trifluoromethylethyl, 4-fluorobutyl,
4-chlorobutyl, 4-bromobutyl, 2,2,3,3,4,4,4-heptafluorobutyl,
5-fluoropenty, and 6-fluorohexyl.
[0152] The (C1-C4)haloalkyl means a straight or branched alkyl
having 1 to 4 carbon atoms which is substituted with 1 to 9 same or
different halogen atoms, wherein the halogen atoms have the same
meaning as defined above. Examples of the (C1-C4)haloalkyl include,
but are not limited to, appropriate examples of the above-mentioned
examples of the (C1-C6)haloalkyl.
[0153] The (C3-C6)cycloalkyl means a cycloalkyl having 3 to 6
carbon atoms. Examples of the (C3-C6)cycloalkyl are cyclopropyl,
cyclobutyl, cyclopentyl, and cyclohexyl.
[0154] The (C2-C6)alkenyl means a straight or branched alkenyl
having 2 to 6 carbon atoms. Examples of the (C2-C6)alkenyl include,
but are not limited to, vinyl, 1-propenyl, isopropenyl, 2-propenyl,
1-butenyl, 1-methyl-1-propenyl, 2-methyl-1-propenyl, 2-butenyl,
1,3-butadienyl, 1-pentenyl, and 1-hexenyl.
[0155] The (C2-C4)alkenyl means a straight or branched alkenyl
having 2 to 4 carbon atoms. Examples of the (C2-C4)alkenyl include,
but are not limited to, appropriate examples of the above-mentioned
examples of the (C2-C6)alkenyl.
[0156] The (C2-C6)alkynyl means a straight or branched alkynyl
having 2 to 6 carbon atoms. Examples of the (C2-C6)alkynyl include,
but are not limited to, ethynyl, 1-propynyl, 2-propynyl, 1-butynyl,
1-methyl-2-propynyl, 2-butynyl, 1-pentynyl, and 1-hexynyl.
[0157] The (C2-C4)alkynyl means a straight or branched alkynyl
having 2 to 4 carbon atoms. Examples of the (C2-C4)alkynyl include,
but are not limited to, appropriate examples of the above-mentioned
examples of the (C2-C6)alkynyl.
[0158] The (C1-C6)alkoxy means a (C1-C6)alkyl-O--, wherein the
(C1-C6)alkyl moiety has the same meaning as defined above. Examples
of the (C1-C6)alkoxy include, but are not limited to, methoxy,
ethoxy, propoxy, isopropoxy, butoxy, sec-butoxy, isobutoxy,
tert-butoxy, pentyloxy, isopentyloxy, neopentyloxy, and
hexyloxy.
[0159] The (C1-C4)alkoxy means a (C1-C4)alkyl-O--, wherein the
(C1-C4)alkyl moiety has the same meaning as defined above. Examples
of the (C1-C4)alkoxy include, but are not limited to, appropriate
examples of the above-mentioned examples of the (C1-C6)alkoxy.
[0160] The cyclic hydrocarbon group means a cyclic group which is
aromatic or non-aromatic and is monocyclic or multicyclic, wherein
all of the ring-constituting atoms are carbon atoms.
[0161] In one embodiment, examples of the cyclic hydrocarbon group
include, but are not limited to, a 3- to 14-membered (preferably 5-
to 14-membered, more preferably 5- to 10-membered) cyclic
hydrocarbon group which is aromatic or non-aromatic and is
monocyclic, bicyclic or tricyclic. In another embodiment, examples
of the cyclic hydrocarbon group include, but are not limited to, a
4- to 8-membered (preferably 5- to 6-membered) cyclic hydrocarbon
group which is aromatic or non-aromatic and is monocyclic or
bicyclic (preferably monocyclic).
[0162] Examples of the cyclic hydrocarbon group include, but are
not limited to, cycloalkyls and aryls.
[0163] The aryls are aromatic cyclic groups among the cyclic
hydrocarbon groups as defined above.
[0164] The cyclic hydrocarbon group as defined or exemplified above
may include a non-condensed cyclic group (e.g., a monocyclic group
or a spirocyclic group) and a condensed cyclic group, when
possible.
[0165] The cyclic hydrocarbon group as defined or exemplified above
may be unsaturated, partially saturated or saturated, when
possible.
[0166] The cyclic hydrocarbon group as defined or exemplified above
is also referred to as a carbocyclic ring group.
[0167] The carbocyclic ring is a ring which corresponds to the
cyclic hydrocarbon group as defined or exemplified above.
[0168] Herein, there are no particular limitations on the
"substituent(s)" for the phrase "optionally substituted" as long as
they are chemically acceptable and exhibit the effects of the
present invention.
[0169] Herein, examples of the "substituent(s)" for the phrase
"optionally substituted" include, but are not limited to, one or
more substituents (preferably 1 to 4 substituents) selected
independently from Substituent Group (a).
[0170] Substituent Group (a) is a group comprising a halogen atom;
a nitro group; a cyano group; a hydroxy group; an amino group;
(C1-C6)alkyl; (C1-C6)haloalkyl; (C3-C6)cycloalkyl; (C2-C6)alkenyl;
(C2-C6)alkynyl; (C1-C6)alkoxy; phenyl; and phenoxy.
[0171] In addition, one or more substituents (preferably 1 to 4
substituents) selected independently from Substituent Group (a) may
each independently have one or more substituents (preferably 1 to 4
substituents) selected independently from Substituent Group
(b).
[0172] In this context, Substituent Group (b) is the same as
Substituent Group (a).
[0173] Herein, a compound having isomers includes all of the
isomers and any mixture thereof in any ratio. For example, xylene
includes o-xylene, m-xylene, p-xylene and any mixture thereof in
any ratio. For example, dichlorobenzene includes o-dichlorobenzene,
m-dichlorobenzene, p-dichlorobenzene and any mixture thereof in any
ratio.
[0174] The process of the present invention includes, in one
embodiment, the following scheme, wherein R.sup.1, R.sup.2 and X
are as defined in [1].
##STR00010##
[0175] (Step (C))
[0176] The step (C) will be described.
[0177] The reaction of the step (C) is halogenation (preferably,
chlorination).
[0178] The step (C) is a step of producing a compound of the
formula (4), that is, a 3-halogenated-4,5-dihydroisoxazole compound
(preferably, a 3-chloro-4,5-dihydroisoxazole compound) by reacting
a compound of the formula (3), that is, a
3-unsubstituted-4,5-dihydroisoxazole compound, with a halogenating
agent (preferably, a chlorinating agent) in the presence of a
nitrile solvent. The 3-halogenated-4,5-dihydroisoxazole compound is
also referred to as a 3-halogeno-4,5-dihydroisoxazole compound. In
other words, the step (C) is a step of producing a compound of the
formula (4) by halogenating (preferably, chlorinating) a compound
of the formula (3) in the presence of a nitrile solvent.
##STR00011##
[0179] In the formula, R.sup.1, R.sup.2 and X are as defined
above.
[0180] (Raw Material in Step (C); Compound of Formula (3))
[0181] A compound of the formula (3) is used as a raw material in
the step (C). The compound of the formula (3) may be a known
compound or may be produced from a known compound according to a
known process. Specific examples of the compound of the formula (3)
include, but are not limited thereto;
5,5-dimethyl-4,5-dihydroisoxazole,
5-ethyl-5-methyl-4,5-dihydroisoxazole,
5,5-diethyl-4,5-dihydroisoxazole,
5-isopropyl-5-methyl-4,5-dihydroisoxazole,
5-(tert-butyl)-5-methyl-4,5-dihydroisoxazole,
5-(chloromethyl)-5-methyl-4,5-dihydroisoxazole,
5-methyl-5-(trifluoromethyl)-4,5-dihydroisoxazole,
5-cyclopropyl-5-methyl-4,5-dihydroisoxazole,
5-oxa-6-azaspiro[3.4]oct-6-ene, 1-methyl-2-methyl[4.4]non-2-ene,
1-methyl-2-methyl[4.5]dec-2-ene,
5-butyl-5-methyl-4,5-dihydroisoxazole,
5-methyl-5-(4-methylpent-3-en-1-yl)-4,5-dihydroisoxazole,
5-methyl-5-(4-methylpentyl)-4,5-dihydroisoxazole,
4'H-spiro[fluorene-9,5'-isoxazole],
5,5-diphenyl-4,5-dihydroisoxazole,
5,5-bis(4-methylphenyl)-4,5-dihydroisoxazole,
5,5-bis(4-methoxyphenyl)-4,5-dihydroisoxazole,
5,5-bis(4-chlorophenyl)-4,5-dihydroisoxazole,
5-methyl-5-phenyl-4,5-dihydroisoxazole,
5-ethyl-5-phenyl-4,5-dihydroisoxazole,
5-(4-methylphenyl)-5-methyl-4,5-dihydroisoxazole,
5-(4-methoxyphenyl)-5-methyl-4,5-dihydroisoxazole, and
5-(4-chlorophenyl)-5-methyl-4,5-dihydroisoxazole. From the
viewpoint of the usefulness of a product, etc., preferable specific
examples of the compound of the formula (3) include
5,5-dimethyl-4,5-dihydroisoxazole,
5-ethyl-5-methyl-4,5-dihydroisoxazole, and
5,5-diethyl-4,5-dihydroisoxazole, more preferably
5,5-dimethyl-4,5-dihydroisoxazole.
[0182] (Halogenating Agent in Step (C))
[0183] The halogenating agent to be used in the step (C) may be any
halogenating agent as long as the reaction proceeds. Examples of
halogenating agents that can be used in the step (C) include
chlorinating agents and brominating agents, preferably chlorinating
agents.
[0184] (Chlorinating Agent in Step (C))
[0185] The chlorinating agents to be used in the step (C) may be
any chlorinating agent as long as the reaction proceeds. Examples
of chlorinating agents that can be used in the step (C) include,
but are not limited to, chlorine (i.e., chlorine molecule;
Cl.sub.2, in other words, elemental chlorine), sulfuryl chloride,
N-chloroimides (e.g., N-chlorosuccinimide and
1,3-dichloro-5,5-dimethylhydantoin), hypochlorite esters (e.g.,
tert-butyl hypochlorite). From the viewpoints of reactivity,
selectivity, economic efficiency, etc., a preferable example of the
chlorinating agent in the step (C) is chlorine (that is, chlorine
molecule; Cl.sub.2).
[0186] The chlorinating agent in the step (C) may be used alone or
in combination of two or more kinds in any ratio. The form of the
chlorinating agent in the step (C) may be any form as long as the
reaction proceeds. The form of the chlorinating agent in the step
(C) can be appropriately selected by a person skilled in the
art.
[0187] When chlorine (that is, chlorine molecule; Cl.sub.2) is used
as the chlorinating agent in the step (C), the form may be any form
as long as the reaction proceeds. Examples of the form include gas
and liquid, preferably gas. Thus, for example, chlorine gas or
liquefied chlorine, preferably chlorine gas is used.
[0188] The amount of the chlorinating agent used in the step (C)
can be appropriately adjusted by a person skilled in the art.
However, when chlorine (that is, chlorine molecule; Cl.sub.2;
preferably, chlorine gas) is used as the chlorinating agent in the
step (C), the amount of the agent used may be any amount as long as
the reaction proceeds. Meanwhile, from the viewpoint of yield,
suppression of by-product formation, economic efficiency, etc., the
amount may be, for example, in the range of 0.5 to 2.0 mol,
preferably 0.9 to 2.0 mol, more preferably 0.9 to 1.5 mol, and even
more preferably 1.0 to 1.2 mol based on 1 mol of the compound of
the formula (3). Also when the other chlorinating agent described
above is used, the same examples of the amount thereof can be
mentioned.
[0189] (Brominating Agent in Step (C))
[0190] The brominating agents to be used in the step (C) may be any
brominating agent as long as the reaction proceeds. Examples of
brominating agents that can be used in the step (C) include, but
are not limited to, bromine (i.e., bromine molecule; Br.sub.2, in
other words, elemental bromine) and N-bromoimides (e.g.,
N-bromosuccinimide, etc.).
[0191] The brominating agent in the step (C) may be used alone or
in combination of two or more kinds in any ratio. The form of the
brominating agent in the step (C) may be any form as long as the
reaction proceeds. The form of the brominating agent in the step
(C) can be appropriately selected by a person skilled in the art.
The amount of the brominating agent used in the step (C) can be
appropriately adjusted by a person skilled in the art.
[0192] (Solvent in Step (C))
[0193] From the viewpoints of smooth progress of the reaction,
etc., it is preferable to perform the reaction of the step (C) in
the presence of a solvent. From the viewpoint of yield, suppression
of by-products, reactivity, economic efficiency, etc., the reaction
of the step (C) is preferably performed in the presence of a
nitrile solvent, and more preferably the reaction of the step (C)
is performed in the presence of a nitrile solvent and a water
solvent. As long as the reaction proceeds, a solvent other than the
nitrile solvent and the water solvent may be used in combination.
As to examples of the solvent other than the nitrile solvent and
the water solvent, reference can be made to appropriate examples of
the examples of the solvent that can be used in the step (D)
described later. As long as the reaction proceeds, the solvent
either may form a single layer or may be separated into two layers,
but preferably forms a uniform single layer.
[0194] As long as the reaction proceeds, examples of the nitrile
solvent in the step (C) include, but are not limited to,
acetonitrile, propionitrile, etc., and any combination thereof in
any ratio. However, from the same viewpoints as described above,
the preferable nitrile solvent is acetonitrile.
[0195] Accordingly, from the viewpoints of yield, suppression of
by-products, reactivity, economic efficiency, etc., preferable
examples of the reaction solvent in the step (C) include nitriles
(e.g., acetonitrile and propionitrile), water, and any combination
thereof in any ratio. A more preferable example is a mixed solvent
of acetonitrile and water (i.e., aqueous acetonitrile). The effect
of the nitrile solvent (preferably, acetonitrile; more preferably,
aqueous acetonitrile) is explained by working examples below. In
addition, from the viewpoint of ease of handling and recycling, it
was unexpectedly found during the investigation of the present
invention that the nitrile solvent of the present invention
(preferably, acetonitrile; more preferably, aqueous acetonitrile)
is preferred in an industrial aspect to tert-butanol, which is a
specific and most preferable reaction solvent in JP 2013-512201 A
(Patent Document 2). For example, the solvent system of the present
invention was found to be superior to the solvent system of the
prior art (Patent Document 2) in terms of the stability of the
solvent, the effective use of hydrogen chloride produced in the
chlorination step as an acid catalyst in the next step, the
viscosity and uniformity of the reaction mixture, the potential of
causing clogging of a reflux condenser or a pipeline in a plant,
etc.
[0196] From the same viewpoints as described above, in one
embodiment, the amount of the nitrile solvent to be used in the
reaction of the step (C) is generally 0.1 to 5.0 L (liters),
preferably 0.3 to 4.0 L, more preferably 0.3 to 3.0 L, further
preferably 0.4 to 3.0 L, further preferably 0.4 to 2.0 L, further
preferably 0.5 to 2.0 L, and further preferably 0.5 to 1.0 L based
on 1 mol of the compound of the formula (3). In another embodiment,
it is preferably 0.1 to 2.0 L, more preferably 0.2 to 2.0 L,
further preferably 0.3 to 2.0 L, further preferably 0.3 to 1.5 L,
further preferably 0.4 to 1.5 L, further preferably 0.5 to 1.5 L,
and further preferably 0.5 to 1.0 L.
[0197] From the same viewpoints as described above, in one
embodiment, the amount of the water solvent to be used in the
reaction of the step (C) is generally 0.00 to 1.00 L, preferably
0.10 to 1.00 L, more preferably 0.10 to 0.80 L, further preferably
0.10 to 0.50 L, further preferably 0.10 to 0.40 L, further
preferably 0.13 to 0.40 L, further preferably 0.15 to 0.40 L, and
further preferably 0.15 to 0.33 L based on 1 mol of the compound of
the formula (3), and the range of 0.13 to 0.35 L is also
mentioned.
[0198] From the same viewpoint as described above, in one
embodiment, the amount of water (vol %) to be used in the reaction
of the step (C) is generally 0 (zero) vol % to 50 vol % or less,
preferably more than 0 (zero) vol % to 50 vol % or less, more
preferably 5 vol % or more and 50 vol % or less, further preferably
5 vol % or more and 40 vol % or less, further preferably 10 vol %
or more and 42 vol % or less, further preferably 10 vol % or more
and 40 vol % or less, further preferably 20 vol % or more and 40
vol % or less, and further preferably 20 vol % or more and 30 vol %
or less of the amount of the mixed solvent of the nitrile solvent
(preferably acetonitrile) and water. A range of 10% vol to 30 vol %
is also mentioned.
[0199] (Reaction Temperature in Step (C))
[0200] The reaction temperature of the step (C) is not particularly
limited. From the viewpoints of yield, suppression of by-products,
economic efficiency, etc., in one embodiment, the reaction
temperature may be, for example, in the range of -30.degree. C.
(minus 30.degree. C.) to 160.degree. C., preferably -10.degree. C.
to 80.degree. C., more preferably -10.degree. C. to 40.degree. C.,
further preferably -5.degree. C. to 30.degree. C., and further more
preferably 0.degree. C. to 30.degree. C. From the same viewpoint as
described above, in another embodiment, the reaction temperature
may be, for example, preferably -5.degree. C. to 50.degree. C.,
more preferably -5.degree. C. to 40.degree. C., further preferably
0.degree. C. to 40.degree. C., and further more preferably
0.degree. C. to 30.degree. C.
[0201] (Reaction Time in Step (C))
[0202] The reaction time in the step (C) is not particularly
limited. From the viewpoints of yield, suppression of by-products,
economic efficiency, etc., in one embodiment, the reaction time may
be, for example, in the range of 0.5 hours to 48 hours, preferably
0.5 hours to 24 hours, and more preferably 1 hour to 12 hours.
[0203] (Product in Step (C); Compound of Formula (4))
[0204] The product in the step (C) is a compound of the formula
(4), in which the isoxazoline ring of the compound of the formula
(3) used as a raw material is halogenated at the 3-position
thereof.
[0205] Preferable specific examples of the compound of the formula
(4) include the following, but are not limited thereto;
3-chloro-5,5-dimethyl-4,5-dihydroisoxazole,
3-bromo-5,5-dimethyl-4,5-dihydroisoxazole,
3-chloro-5-ethyl-5-methyl-4,5-dihydroisoxazole,
3-bromo-5-ethyl-5-methyl-4,5-dihydroisoxazole,
3-chloro-5,5-diethyl-4,5-dihydroisoxazole, and
3-bromo-5,5-diethyl-4,5-dihydroisoxazole.
[0206] From the viewpoints of economic efficiency, usefulness of
the product, etc., more preferable specific examples of the
compound of the formula (4) include
3-chloro-5,5-dimethyl-4,5-dihydroisoxazole, 3-chloro
-5-ethyl-5-methyl-4,5-dihydroisoxazole, and
3-chloro-5,5-diethyl-4,5-dihydroisoxazole, and further preferably
3-chloro-5,5-dimethyl-4,5-dihydroisoxazole. The compound of the
formula (4), which is the product in the step (C), can be used as a
raw material in the step (D).
[0207] (Step (D))
[0208] The step (D) will be described.
[0209] The reaction in the step (D) is isothiouronium
formation.
[0210] The step (D) is a step of producing a
(4,5-dihydroisoxazol-3-yl)]thiocarboxamidine salt compound of the
formula (5) (i.e., an isothiouronium compound) by reacting a
compound of the formula (4) with an isothiouronium-forming agent.
"Isothiouronium" is also referred to as "isothiuronium".
##STR00012##
[0211] In the formula, R.sup.1, R.sup.2 and X are as defined
above.
[0212] (Raw Material of Step (D); Compound of Formula (4))
[0213] The compound of the formula (4) is used as a raw material
for the process of the present invention. The compound of the
formula (4) may be a known compound or may be produced from a known
compound according to a known process. In addition, the compound of
the formula (4) can be produced by the process of the above step
(C). In this case, the compound of the formula (4) may be used for
the next step after being isolated in the step (C), or may be used
for the next step after further purification, or may be used for
the next step without isolation.
[0214] When the compound of the formula (4) is not isolated or
purified in the step (C), the step (D) may be performed in the same
reaction vessel in which the step (C) was performed.
[0215] Specific examples, preferable specific examples, more
preferable specific examples, and further preferable specific
examples of the compound of the formula (4) are as described
above.
[0216] (Isothiouronium-Forming Agent in Step (D))
[0217] The isothiouronium-forming agent used in step (D) may be any
isothiouronium-forming agent as long as the reaction proceeds.
However, as the isothiouronium-forming agent to be used in the step
(D), thiourea is commonly used.
[0218] When thiourea is used as the isothiouronium-forming agent in
the step (D), the amount of the thiourea used may be any amount as
long as the reaction proceeds. From the viewpoints of yield,
suppression of by-products, economic efficiency, etc., in one
embodiment, the amount of the thiourea used may be, for example, in
the range of 0.5 to 2.0 mol, preferably 0.9 to 1.5 mol, and more
preferably 1.0 to 1.2 mol based on 1 mol of the compound of the
formula (4). Also when an isothiouronium-forming agent other than
thiourea is used, the same examples of the amount thereof can be
mentioned.
[0219] (Solvent in Step (D))
[0220] From the viewpoints of smooth progress of the reaction,
etc., it is preferable to perform the reaction of the step (D) in
the presence of a solvent. When the step (D) is performed in the
same reaction vessel in which the step (C) was performed, no
solvent may be further added, or a solvent may be added. Further,
when the reaction mixture of the step (C) is transferred to another
reaction vessel and then the reaction of the step (D) is performed
without isolating the compound of the formula (4), no solvent may
be further added, or a solvent may be added. In any case, any
solvent may be added as long as the reaction in the step (D)
proceeds. Further, a part or the whole of the solvent used in the
step (C) may be removed between the step (C) and the step (D) as
long as the reaction proceeds. The amount of the solvent to be
removed is not particularly limited. When the step (D) is performed
after the compound of the formula (4) is isolated or purified in
the step (C), the solvent in the step (D) may be any solvent as
long as the reaction proceeds.
[0221] As to the reaction solvent in the step (D), examples of the
solvent that can be used in any case described above include, but
are not limited to, nitriles (e.g., acetonitrile and
propionitrile); water; alcohols (e.g., methanol, ethanol, and
2-propanol); ethers (e.g., tetrahydrofuran (THF), 1,4-dioxane,
diisopropyl ether, dibutyl ether, di-tert-butyl ether, cyclopentyl
methyl ether (CPME), methyl-tert-butyl ether, 1,2-dimethoxyethane
(DME), diglyme, and triglyme); amides (e.g., N,N-dimethylformamide
(DMF), N,N-dimethylacetamide (DMAC), and N-methylpyrrolidone
(NMP)); alkyl ureas (e.g., N,N'-dimethylimidazolidinone (DMI));
sulfoxides (e.g., dimethylsulfoxide (DMSO)); carboxylic acid esters
(e.g., ethyl acetate and butyl acetate); aromatic hydrocarbon
derivatives (e.g., benzene, toluene, xylene, chlorobenzene, and
dichlorobenzene); and halogenated aliphatic hydrocarbons (e.g.,
dichloromethane, chloroform, and dichloroethane), and any
combination thereof in any ratio. The amount of the reaction
solvent used in the step (D) may be any amount as long as the
reaction system can be sufficiently stirred. When a combination of
two or more solvents is used, the ratio thereof may be any ratio as
long as the reaction proceeds. As long as the reaction proceeds,
the solvent either may form a single layer or may be separated into
two layers, but preferably forms a uniform single layer.
[0222] However, from the viewpoints of smooth progress of the
reaction, economic efficiency, etc., preferable examples and more
preferable examples of the solvent in the step (D) are the same as
those in the step (C). In these cases, preferable examples, more
preferable examples, and further preferable examples of the amounts
of the solvents to be used in the step (D) (that is, the amounts of
the nitrile solvent and the water solvent) are the same as those in
the step (C). In addition, preferable examples, more preferable
examples, and even more preferable examples of the amount of water
(vol %) based on the amount of the mixed solvent of the nitrile
solvent (preferably acetonitrile) and water are the same as those
in the step (C).
[0223] Furthermore, from the same viewpoints as described above, in
one embodiment, the reaction of the step (C) and the reaction of
the step (D) are preferably performed in the same solvent, but are
not limited to this mode.
[0224] (Reaction Temperature in Step (D))
[0225] The reaction temperature in the step (D) is not particularly
limited. From the viewpoints of yield, suppression of by-products,
economic efficiency, etc., in one embodiment, the reaction
temperature may be, for example, in the range of -30.degree. C.
(minus 30.degree. C.) to 160.degree. C., preferably -10.degree. C.
to 80.degree. C., more preferably 0.degree. C. to 40.degree. C.,
even more preferably 10.degree. C. to 40.degree. C., further
preferably 10.degree. C. to 30.degree. C., and further more
preferably 15.degree. C. to 30.degree. C. From the same viewpoints
as described above, in another embodiment, the reaction temperature
may be, for example, preferably in the range of 0.degree. C. to
80.degree. C., more preferably 0.degree. C. to 60.degree. C.,
further preferably 15.degree. C. to 60 .degree. C., and further
more preferably 15.degree. C. to 40.degree. C.
[0226] (Reaction Time in Step (D))
[0227] The reaction time in the step (D) is not particularly
limited. From the viewpoints of yield, suppression of by-products,
economic efficiency, etc., in one embodiment, the reaction time may
be, for example, in the range of 0.5 hours to 48 hours, preferably
0.5 hours to 24 hours, more preferably 1 hour to 12 hours, and even
more preferably 1 hour to 8 hours.
[0228] (Product in Step (D); Compound of Formula (5))
[0229] The product in the step (D) is a thiocarboxamidine salt
compound of the formula (5) (i.e., an isothiouronium compound)
corresponding to the compound of the formula (4) used as a raw
material.
[0230] Preferable specific examples of compound of the formula (4)
include the following, but are not limited thereto;
[5,5-dimethyl(4,5-dihydroisoxazol-3-yl)]thiocarboxamidine
hydrochloride,
[5,5-dimethyl(4,5-dihydroisoxazol-3-yl)]thiocarboxamidine
hydrobromide,
[5-ethyl-5-methyl(4,5-dihydroisoxazol-3-yl)]thiocarboxamidine
hydrochloride,
[5-ethyl-5-methyl(4,5-dihydroisoxazol-3-yl)]thiocarboxamidine
hydrobromide,
[5,5-diethyl(4,5-dihydroisoxazol-3-yl)]thiocarboxamidine
hydrochloride, and
[5,5-diethyl(4,5-dihydroisoxazol-3-yl)]thiocarboxamidine
hydrobromide.
[0231] From the viewpoints of economic efficiency, usefulness of
the product, etc., more preferable specific examples of the
compound of the formula (4) are
[5,5-dimethyl(4,5-dihydroisoxazol-3-yl)]thiocarboxamidine
hydrochloride,
[5-ethyl-5-methyl(4,5-dihydroisoxazol-3-yl)]thiocarboxamidine
hydrochloride,
[5,5-diethyl(4,5-dihydroisoxazol-3-yl)]thiocarboxamidine
hydrochloride, and more preferably
[5,5-dimethyl(4,5-dihydroisoxazol-3-yl)]thiocarboxamidine
hydrochloride.
[0232] Unless otherwise indicated, it is understood that numbers
used herein to express characteristics such as quantities, sizes,
concentrations, and reaction conditions are modified by the term
"about". In some embodiments, disclosed numerical values are
interpreted applying the reported number of significant digits and
conventional rounding techniques. In some embodiments, disclosed
numerical values are interpreted as containing certain errors
necessarily resulting from the standard deviation found in their
respective testing measurements.
[0233] Hereinafter, the present invention will be described in more
detail by Examples, but the present invention is not limited in any
way by these Examples.
[0234] Herein, the following instruments and conditions were used
for the analysis in the examples and comparative examples.
[0235] (.sup.1H-NMR: .sup.1H Nuclear Magnetic Resonance
Spectrum)
[0236] Instrument: JEOL JMN-ECS-300 or JEOL JMN-Lambda-400
(manufactured by JEOL RESONANCE Ltd.), solvent: CDCl.sub.3 and/or
DMSO-d.sub.6, internal standard substance: tetramethylsilane (TMS)
and others.
[0237] (GC Analysis: Gas Chromatography Analysis)
[0238] GC-2025 (manufactured by Shimadzu Corporation), detection
method: FID
[0239] Gas chromatography (GC) analysis method; regarding the GC
analysis method, the following documents can be referred to, if
necessary.
[0240] Document (a): "Shin-Jikkenkagaku Koza 9, Bunseki Kagaku II
(A New Course in Experimental Chemistry 9, Analytical Chemistry
II)", pp. 60 to 86 (1977), edited by The Chemical Society of Japan,
published by Shingo Iizumi, Maruzen Co., Ltd. (for example, page 66
of this document can be referred to with respect to liquids for a
stationary phase to be usable for a column).
[0241] Document (b): "Jikkenkagaku Koza 20-1, Bunseki Kagaku (A
Course in Experimental Chemistry 20-1, Analytical Chemistry)", 5th
edition, pp. 121 to 129 (2007), edited by The Chemical Society of
Japan, published by Seishiro Murata, Maruzen Co., Ltd. (for
example, pages 124 to 125 of this document can be referred to with
respect to the specific usage of hollow capillary separation
columns).
[0242] (GC-MS Analysis: Gas Chromatography Mass Spectrometry
Analysis)
[0243] Analysis instrument: 6890N Network GC System (manufactured
by Agilent Technologies), mass detector: 5973N MSD (manufactured by
Agilent Technologies)
[0244] Herein, room temperature and ambient temperature are from
15.degree. C. to 30.degree. C.
EXAMPLE 1
Production of
[5,5-dimethyl(4,5-dihydroisoxazol-3-yl)]thiocarboxamidine
hydrochloride (5-a)
[0245] Step (C; Chlorination) and Step (D; Formation of
Isothiouronium)
##STR00013##
(1) Production of 3-chloro-5,5-dimethyl-4,5-dihydroisoxazole
(4-a)
[0246] Step (C; Chlorination)
[0247] 5,5-Dimethyl-4,5-dihydroisoxazole (3-a; 186 mg, 1.88 mmol,
100 mol %) was dissolved in acetonitrile (0.94 ml, 0.5 L
(liters)/mol, based on (3-a)) and water (0.28 ml, 0.15 L/mol, based
on (3-a)). Chlorine gas (50 ml as gas, measured with a gas tight
syringe at 25.degree. C., gas specific gravity: 2.935 g/L (liter)
(25.degree. C.), 0.147 g, 2.07 mmol, 110 mol %) was introduced
thereto at 25 to 30.degree. C., and the mixture was stirred at the
same temperature for 1 hour. The GC-MS analysis of the reaction
mixture confirmed the formation of the target
3-chloro-5,5-dimethyl-4,5-dihydroisoxazole (4-a). As a result of
the GC analysis (area percentage) of the reaction mixture, the
components in the reaction mixture excluding the solvents and the
like were as follows:
[0248] 3-chloro-5,5-dimethyl-4,5-dihydroisoxazole (4-a; target
intermediate): 99%.
(2) Production of
[5,5-dimethyl(4,5-dihydroisoxazol-3-yl)]thiocarboxamidine
hydrochloride (5-a)
[0249] Step (D; Formation of Isothiouronium)
[0250] Then, thiourea (143 mg, 1.88 mmol, 100 mol %) was added
thereto, and the mixture was stirred at room temperature for 15
hours. After the completion of the reaction, the reaction mixture
was concentrated under reduced pressure to obtain
[5,5-dimethyl(4,5-dihydroisoxazol-3-yl)]thiocarboxamidine
hydrochloride (5-a; 386 mg, 1.84 mmol, yield: 98%).
[0251] .sup.1H-NMR (400 MHz, CDCl.sub.3-DMSO-d.sub.6) .delta. (ppm,
relative to TMS): 1.48 (s, 6H), 2.99 (s, 2H), 9.63 (bs, 2H), 9.88
(bs, 2H).
EXAMPLES 2 to 21 AND COMPARATIVE EXAMPLE 1
Production of 3-chloro-5,5-dimethyl-4,5-dihydroisoxazole (4-a)
[0252] Step (C; Chlorination)
##STR00014##
[0253] The chlorination in the step (C) was performed in the same
manner as in Example 1 (1) except that the solvent was changed as
shown in Table 1 below. The results of the GC analysis (area
percentage) of the reaction mixture are shown in Table 1 below for
the target product, the raw material, and other by-products. In
addition, Table 1 also shows the result of Example 1 (1).
TABLE-US-00001 TABLE 1 Amount Ratio in Reaction of Water Mixture
(%) Nitrile Contained (4-a) (3-a) solvent Water in Solvent Target
Raw By- Example (L/mol) (L/mol) (vol %) Unformity Product Material
products Example2 CH.sub.3CN 1.00 0 0 94 1 5 Example3 CH.sub.3CN
1.00 0.09 8 93 0 7 Example4 CH.sub.3CN 1.00 0.15 13 97 0 3 Example5
CH.sub.3CN 1.00 0.33 25 97 2 1 Example6 CH.sub.3CN 1.00 0.50 33 x
90 6 4 Example7 CH.sub.3CN 0.50 0 0 90 0 10 Example8 CH.sub.3CN
0.50 0.06 10 61 0 39 Example9 CH.sub.3CN 0.50 0.10 17 77 1 22
Example1 CH.sub.3CN 0.50 0.15 23 99 1 0 Example10 CH.sub.3CN 0.50
0.20 29 99 0 1 Example11 CH.sub.3CN 0.50 0.33 40 99 0 1 Example12
CH.sub.3CN 0.50 0.40 44 x 84 13 3 Example13 CH.sub.3CN 0.50 0.50 50
x 84 12 4 Example14 CH.sub.3CN 0.35 0.15 30 x 84 2 14 Example15
CH.sub.3CN 0.30 0.20 40 x 79 5 16 Example16 CH.sub.3CN 0.20 0 0 88
0 12 Example17 C.sub.2H.sub.5CN 0.50 0 0 89 0 11 Example18
C.sub.2H.sub.5CN 0.50 0.10 17 x 91 0 9 Example19 C.sub.2H.sub.5CN
0.50 0.20 29 x 93 2 5 Example20 C.sub.2H.sub.5CN 0.50 0.40 44 x 80
14 6 Example21 C.sub.2H.sub.5CN 0.20 0 0 82 0 18 Comparative
CH.sub.3CN 0 0.50 100 x 45 47 8 Example1
[0254] Uniformity .smallcircle.: The reaction mixture was
uniform.
[0255] Uniformity .times.: The reaction mixture separated into two
layers.
[0256] When only the nitrile solvent was used as the reaction
solvent, the reaction proceeded. However, by-products were also
formed (see Examples 2, 7, 16, 17 and 21). On the other hand, when
only water was used as the reaction solvent, the yield was as low
as 45% (see Comparative Example 1). Even in the presence of the
nitrile solvent and the water solvent, though the reaction
proceeded, there were some examples in which the yield was low
because a large number of small amounts of impurities were produced
as by-products (see Examples 8, 9, 14, 15, and 18). Surprisingly,
however, in the presence of an appropriate amount of the nitrile
solvent and an appropriate amount of the water solvent, extremely
high yields were achieved with reduced formation of impurities
(by-products). This surprising effect was particularly observed
when the nitrile solvent was acetonitrile (CH.sub.3CN), and very
satisfactory yields were obtained (see Examples 1, 4, 5, 10 and
11). Further, according to the process of the present invention, an
extremely high yield was achieved in the step (D) in a short time
(see Example 1 (2)).
EXAMPLE 22
Production of 3-chloro-5,5-dimethyl-4,5-dihydroisoxazole (4-a)
[0257] Step (C; Chlorination)
##STR00015##
[0258] 5,5-Dimethyl-4,5-dihydroisoxazole (3-a; 5.0 g, 50.4 mmol,
100 mol %) was dissolved in acetonitrile (25 ml, 0.5 L
(liters)/mol, based on (3-a)) and water (10 ml, 0.2 L/mol, based on
(3-a)). While stirring with a magnetic stirrer, chlorine gas (2.6
ml, liquefied at -70.degree. C. and measured, specific gravity:
1.64 (-70.degree. C.), 4.3 g, 60.5 mmol, 120 mol %) was introduced
thereto at 2 to 5.degree. C. over 30 minutes, and the mixture was
stirred at the same temperature for 1 hour. As a result of the GC
analysis (area percentage) of the reaction mixture, the components
in the reaction mixture excluding the solvents and the like were as
follows:
[0259] 3-chloro-5,5-dimethyl-4,5-dihydroisoxazole (4-a; target
product): 98%.
[0260] After the completion of the reaction, ethyl acetate (25 ml),
a 1 M sodium thiosulfate (Na.sub.2S.sub.2O.sub.3) aqueous solution
(5 ml) and a saturated sodium chloride aqueous solution (10 ml)
were added to the reaction mixture, and the mixture was stirred.
The organic layer and the aqueous layer were separated from each
other, so that the organic layer was obtained. The organic layer
was washed with a small amount of a saturated sodium hydrogen
carbonate (NaHCO.sub.3) aqueous solution and then was concentrated
under reduced pressure until the volume of the organic layer was
reduced to about 10 ml. Dichloromethane (25 ml) was added thereto,
and the organic layer was dried over magnesium sulfate and
concentrated under reduced pressure. The resultant crude product
was purified by distillation to obtain
3-chloro-5,5-dimethyl-4,5-dihydroisoxazole (4-a, colorless oil, 5.8
g, purity: 99.9% (GC area percentage), 43.4 mmol, yield: 86%,
boiling point: 70 to 72.degree. C./20 Torr).
[0261] .sup.1H-NMR (400 MHz, CDCl.sub.3) .delta. (ppm, relative to
TMS): 1.46 (s, 6H), 2.93 (s, 2H).
EXAMPLE 23
Production of
[5,5-dimethyl(4,5-dihydroisoxazol-3-yl)]thiocarboxamidine
hydrochloride (5-a)
[0262] Step (C; Chlorination) and Step (D; Formation of
Isothiouronium)
##STR00016##
(1) Production of 3-chloro-5,5-dimethyl-4,5-dihydroisoxazole
(4-a)
[0263] Step (C; Chlorination)
[0264] 5,5-Dimethyl-4,5-dihydroisoxazole (3-a; 10.0 g, 101 mmol,
100 mol %) was dissolved in acetonitrile (50 ml, 0.5 L
(liters)/mol, based on (3-a)) and water (20 ml, 0.2 L/mol, based on
(3-a)). While stirring with a magnetic stirrer, chlorine gas (5.2
ml, liquefied at -70.degree. C. and measured, specific gravity:
1.64 (-70.degree. C.), 8.6 g, 121 mmol, 120 mol %) was introduced
thereto at 2 to 5.degree. C. over 1 hour, and the mixture was
stirred at the same temperature for 1 hour. As a result of the GC
analysis (area percentage) of the reaction mixture, the components
in the reaction mixture excluding the solvents and the like were as
follows:
[0265] 3-chloro-5,5-dimethyl-4,5-dihydroisoxazole (4-a; target
intermediate): 98%.
(2) Production of
[5,5-dimethyl(4,5-dihydroisoxazol-3-yl)]thiocarboxamidine
hydrochloride (5-a)
[0266] Step (D; Formation of Isothiouronium)
[0267] Then, thiourea (8.5 g, 111 mmol, 110 mol %) was added
thereto, and the mixture was stirred at 30.degree. C. for 7 hours.
The NMR analysis of the reaction mixture confirmed the formation of
the target
[5,5-dimethyl(4,5-dihydroisoxazol-3-yl)]thiocarboxamidine
hydrochloride (5-a). The conversion of
3-chloro-5,5-dimethyl-4,5-dihydroisoxazole (4-a) to
[5,5-dimethyl(4,5-dihydroisoxazol-3-yl)]thiocarboxamidine
hydrochloride (5-a) was 90% at 4 hours after the addition of
thiourea, and 99% at 7 hours after the addition of thiourea.
Acetamide and acetic acid, which could be formed by decomposition
of acetonitrile used as a solvent, were not observed. After the
completion of the reaction, the reaction mixture was concentrated
under reduced pressure. The operation of adding ethanol (20 ml) and
toluene (80 ml) and concentrating the mixture was performed twice,
the resultant crude solid was dissolved in isopropyl alcohol (100
ml), insolubles were removed by filtration, and the resultant
filtrate was concentrated under reduced pressure. The resultant
solid was collected by filtration and washed with ethyl acetate to
obtain [5,5-dimethyl(4,5-dihydroisoxazol-3-yl)]thiocarboxamidine
hydrochloride (5-a; colorless solid, 17.5 g, 83.5 mmol, yield:
83%).
[0268] .sup.1H-NMR (400 MHz, CDCl.sub.3-DMSO-d.sub.6) .delta. (ppm,
relative to TMS): 1.48 (s, 6H), 2.99 (s, 2H), 9.63 (bs, 2H), 9.88
(bs, 2H).
COMPARATIVE EXAMPLE 2
Production of
[5,5-dimethyl(4,5-dihydroisoxazol-3-yl)]thiocarboxamidine
hydrochloride (5-a) Using Tert-Butanol as Reaction Solvent
[0269] Step (C; Chlorination) and Step (D; Formation of
Isothiouronium)
##STR00017##
(1) Production of 3-chloro-5,5-dimethyl-4,5-dihydroisoxazole
(4-a)
[0270] Step (C; Chlorination)
[0271] 5,5-Dimethyl-4,5-dihydroisoxazole (3-a; 10.0 g, 101 mmol,
100 mol %) was dissolved in tert-butanol (20 ml, 0.2 L
(liters)/mol, based on (3-a), the same amount of tert-butanol as in
Example 6 of JP 2013-512201 A (Patent Document 2) was used). While
stirring with a magnetic stirrer, chlorine gas (5.2 ml, liquefied
at -70.degree. C. and measured, specific gravity: 1.64 (-70.degree.
C.), 8.6 g, 121 mmol, 120 mol %) was introduced thereto at 20 to
25.degree. C. over 1 hour, and the mixture was stirred at the same
temperature for 1 hour. As a result of the GC analysis (area
percentage) of the reaction mixture, the components in the reaction
mixture excluding the solvents and the like were as follows:
[0272] 3-chloro-5,5-dimethyl-4,5-dihydroisoxazole (4-a; target
intermediate): 98%.
(2) Production of
[5,5-dimethyl(4,5-dihydroisoxazol-3-yl)]thiocarboxamidine
hydrochloride (5-a)
[0273] Step (D; Formation of Isothiouronium)
[0274] Then, thiourea (8.5 g, 111 mmol, 110 mol %) was added
thereto, and the mixture was stirred at 30.degree. C. After 1 hour,
a white solid presumed to be
[5,5-dimethyl(4,5-dihydroisoxazol-3-yl)]thiocarboxamidine
hydrochloride (5-a) precipitated, so that it became impossible to
continue stirring. The NMR analysis of the reaction mixture
revealed that the conversion of
3-chloro-5,5-dimethyl-4,5-dihydroisoxazole (4-a) to
[5,5-dimethyl(4,5-dihydroisoxazol-3-yl)]thiocarboxamidine
hydrochloride (5-a) was 63%. At this point, 15% of the theoretical
amount of hydrogen chloride generated in the previous step had been
converted to tert-butyl chloride by the reaction with tert-butanol.
The amount of tert-butyl chloride was calculated from the ratio of
the peak area derived from methyl of tert-butyl chloride to the
peak area derived from methyl on the isoxazoline ring of the target
product (5-a).
[0275] tert-Butanol (50 ml, 0.5 L (liters)/mol, based on (3-a)) was
added thereto, and after confirming that the mixture was stirred,
the reaction was continued. Seven hours after the addition of
thiourea, a portion of the reaction mixture was sampled and
analyzed by NMR. As a result, the conversion of
3-chloro-5,5-dimethyl-4,5-dihydroisoxazole (4-a) to
[5,5-dimethyl(4,5-dihydroisoxazol-3-yl)]thiocarboxamidine
hydrochloride (5-a) was 86%. At this point, 49% of the theoretical
amount of hydrogen chloride generated in the previous step had been
converted to tert-butyl chloride.
INDUSTRIAL APPLICABILITY
[0276] The (4,5-dihydroisoxazol-3-yl)thiocarboxamidine salt
compound of the formula (5) produced by the process of the present
disclosure is useful as an intermediate for producing
pharmaceuticals and agricultural chemicals, particularly, a
herbicide pyroxasulfone. According to the present disclosure, the
target compound can be produced in a short time and with a high
yield. According to the present disclosure, it is possible to
produce the target compound by a simple operation without requiring
a special equipment. Therefore, the process of the present
disclosure is industrially preferable, economical, and
environmentally friendly, and has high industrial utility value. In
short, the present disclosure has a high industrial
applicability.
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