U.S. patent application number 17/175582 was filed with the patent office on 2022-08-18 for pleuromutilin salicylic acid ester with antibacterial activity and a method of preparing the same.
This patent application is currently assigned to SHAANXI UNIVERSITY OF SCIENCE AND TECHNOLOGY. The applicant listed for this patent is Ruina BIAN, Han LI, Jingyi LI, Gennian MAO, Liang QI, Chunyang SHI, Bin TIAN, Yongbo WANG, Liang XIN, Jingwen XU, Dan YANG, Wenbo YAO, Jian ZHA, Qianqian ZHAO. Invention is credited to Ruina BIAN, Han LI, Jingyi LI, Gennian MAO, Liang QI, Chunyang SHI, Bin TIAN, Yongbo WANG, Liang XIN, Jingwen XU, Dan YANG, Wenbo YAO, Jian ZHA, Qianqian ZHAO.
Application Number | 20220259138 17/175582 |
Document ID | / |
Family ID | |
Filed Date | 2022-08-18 |
United States Patent
Application |
20220259138 |
Kind Code |
A1 |
ZHAO; Qianqian ; et
al. |
August 18, 2022 |
PLEUROMUTILIN SALICYLIC ACID ESTER WITH ANTIBACTERIAL ACTIVITY AND
A METHOD OF PREPARING THE SAME
Abstract
A compound with anti-drug resistant bacteria activity having the
following formula (I): ##STR00001## is disclosed. The methods of
preparing the compound of formula (I) are also disclosed.
Inventors: |
ZHAO; Qianqian; (Xi'an,
CN) ; XIN; Liang; (Xi'an, CN) ; LI;
Jingyi; (Xi'an, CN) ; BIAN; Ruina; (Xi'an,
CN) ; YANG; Dan; (Xi'an, CN) ; QI; Liang;
(Xi'an, CN) ; TIAN; Bin; (Xi'an, CN) ; ZHA;
Jian; (Xi'an, CN) ; YAO; Wenbo; (Xi'an,
CN) ; MAO; Gennian; (Xi'an, CN) ; LI; Han;
(Xi'an, CN) ; SHI; Chunyang; (Xi'an, CN) ;
WANG; Yongbo; (Xi'an, CN) ; XU; Jingwen;
(Xi'an, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ZHAO; Qianqian
XIN; Liang
LI; Jingyi
BIAN; Ruina
YANG; Dan
QI; Liang
TIAN; Bin
ZHA; Jian
YAO; Wenbo
MAO; Gennian
LI; Han
SHI; Chunyang
WANG; Yongbo
XU; Jingwen |
Xi'an
Xi'an
Xi'an
Xi'an
Xi'an
Xi'an
Xi'an
Xi'an
Xi'an
Xi'an
Xi'an
Xi'an
Xi'an
Xi'an |
|
CN
CN
CN
CN
CN
CN
CN
CN
CN
CN
CN
CN
CN
CN |
|
|
Assignee: |
SHAANXI UNIVERSITY OF SCIENCE AND
TECHNOLOGY
Xi'an
CN
|
Appl. No.: |
17/175582 |
Filed: |
February 12, 2021 |
International
Class: |
C07C 69/88 20060101
C07C069/88; C07C 67/14 20060101 C07C067/14; C07C 67/08 20060101
C07C067/08 |
Claims
1. A compound having the following formula (I): ##STR00005##
23. A method of preparing the compound of formula (I) of claim 1,
comprising: reacting a compound of formula (II) with a compound of
formula (III) to obtain the compound of formula (I):
##STR00006##
3. The method of claim 2, wherein the reaction of the compound of
formula (II) with the compound of formula (III) comprises the
following steps: placing the compound of formula (II) and the
compound of formula (III), in a molar ratio of 1:1 to 1:1.3, in a
reactor; adding an organic solvent and a catalytic amount of
triethylamine under a nitrogen atmosphere to obtain a reaction
mixture; heating the reaction mixture at 20-50.degree. C. for 4-8
hours; concentrating the reaction mixture and extracting with ethyl
acetate to obtain a crude product; and purifying the crude product
on a fresh silica gel chromatography column with petroleum ether
and ethyl acetate as an eluent to obtain the compound of formula
(I).
4. The method of claim 3, wherein the organic solvent is toluene,
dichloromethane, or N,N-dimethylformamide.
5. The method of claim 4, wherein the organic solvent is
dichloromethane.
6. The method of claim 3, wherein the molar ratio of the compound
of formula (II) and the compound of formula (III) is 1:1.1.
7. The method of claim 3, wherein the reaction mixture is heated at
20.degree. C.
8. The method of claim 3, wherein the reaction mixture is heated
for 5 hours.
9. (canceled)
10. A method of preparing the compound of formula (I) of claim 1,
comprising: reacting a compound of formula (II) with a compound of
formula (IV) to obtain the compound of formula (I):
##STR00007##
11. The method of claim 10, wherein the reaction of the compound of
formula (II) with the compound of formula (IV) comprises the
following steps: placing the compound of formula (II), a catalyst,
and an ionic liquid in a reactor under a nitrogen atmosphere, the
catalyst being 12-molybdosilicic acid hydrate of formula
H.sub.6Mo.sub.12O.sub.41Si; adding the compound of formula (IV) to
the reactor to form a reaction mixture; heating the reaction
mixture at 20-40.degree. C. for 2-5 hours; placing the reaction
mixture in a separating funnel to separate a crude product;
purifying the crude product by recrystallization in methanol to
obtain the compound of formula (I); and recycling the ionic
liquid.
12. The method of claim 11, wherein the ionic liquid is 1
octyl-3-methylimidazolium hexafluorophosphate,
1-hexyl-3-methylimidazolium tetrafluoroborate, or
1-butyl-3-methylimidazolium tetrafluoroborate.
13. The method of claim 11, wherein the ionic liquid is
1-octyl-3-methylimidazolium hexafluorophosphate.
14. The method of claim 11, wherein the compound of formula (II)
and the compound (IV) have a molar ratio of 1:1 to 1:1.3.
15. The method of claim 14, wherein the molar ratio of the compound
of formula (II) and the compound of formula (IV) is 1:1.1.
16. The method of claim 11, wherein the reaction mixture is heated
at 25.degree. C.
17. The method of claim 11, wherein the reaction mixture is heated
for 3 hours.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to the field of medicinal
chemistry, and in particular, to pleuromulin salicylic acid ester
with anti-drug resistant bacteria activity and a method of
preparing the same.
BACKGROUND OF THE INVENTION
[0002] Antimicrobials are the most commonly used drugs for the
treatment of bacterial infections. Over the years, with the
popularity and application of antibiotics around the world, as well
as serious unreasonable abuse, a variety of drug-resistant strains
have appeared in both Gram-positive and Gram-negative bacteria.
Among them, the problem of drug resistance of Gram-positive
bacteria is particularly serious. Methicillin-resistant
Staphylococcus aureus and Staphylococcus epidermidis,
penicillin-resistant Streptococcus pneumoniae and
vancomycin-resistant enterococci are serious clinical problems. At
present, there is a lack of effective drugs for the infection
caused by these drug-resistant bacteria. There is an urgent need to
develop new structural antimicrobials without cross-resistance and
more effective.
[0003] Pleuromulin (compound of formula II) belongs to tricyclic
diterpenoid antibiotics. The main structure for its antibacterial
effect is the tricyclic skeleton in the compound, which can form an
inducing fit effect with the peptide acyltransferase active center
(PTC) of the 50S subunit of the bacterial ribosome. Pleuromutilin
antibiotics have certain antibacterial activity against most
Gram-positive bacteria except Enterococcus faecalis. In addition,
pleuromutilin antibiotics also have good in vitro antibacterial
effects against fastidious gram-negative bacteria including
Haemophilus influenzae, Moraxella catarrhalis and Neisseria spp. It
has been more than half a century that pleuromutilin antibiotics
have been discovered. Although the application of these drugs in
veterinary clinics has achieved considerable results, there is no
pleuromutilin antibiotics available for systemic medicine in the
human medicine clinic.
[0004] Salicylic acid (compound of formula IV) is a plant willow
bark extract and a natural anti-inflammatory drug. The commonly
used cold medicine aspirin is sodium acetylsalicylate, a derivative
of salicylic acid. Sodium p-aminosalicylate (PAS) is a commonly
used anti-tuberculosis drug. Salicylic acid is often used in
dermatology to treat various chronic skin diseases, such as acne.
Salicylic acid can remove hominess, sterilization and
anti-inflammation, so it is very suitable for the treatment of acne
caused by clogged pores. International mainstream acne products are
hydrated salicylic acid, and the concentration is usually
0.5-2%.
[0005] In the present invention, pleuromulin is combined with
salicylic acid to obtain a pleuromulin salicylic acid ester.
Preliminary in vitro antibacterial activity experiment shows that
the compound has excellent antibacterial activity and
anti-drug-resistant bacteria activity.
SUMMARY OF THE INVENTION
[0006] In one embodiment, the present invention provides a compound
having the following formula (I) (pleuromulin salicylic acid
ester):
##STR00002##
[0007] In another embodiment, a method of preparing the compound of
formula (I) includes reacting a compound of formula (II) with a
compound of formula (III) to obtain the compound of formula
(I):
##STR00003##
[0008] In another embodiment, the reaction of the compound of
formula (II) with the compound of formula (III) comprises the
following steps: placing the compound of formula (II) and the
compound of formula (III), in a molar ratio of 1:1 to 1:1.3, in a
reactor; adding an organic solvent and a catalytic amount of
triethylamine under nitrogen atmosphere to obtain a reaction
mixture; heating the reaction mixture at 20-50.degree. C. for 4-8
hours; concentrating the reaction mixture and extracting with with
ethyl acetate to obtain a crude product; and purifying the crude
product on a silica gel fresh chromatography column with petroleum
ether and ethyl acetate as an eluent to obtain the compound of
formula (I).
[0009] In another embodiment, the organic solvent is toluene,
dichloromethane, or N,N-dimethylformamide.
[0010] In another embodiment, the organic solvent is
dichloromethane.
[0011] In another embodiment, the molar ratio of the compound of
formula (II) and the compound of formula (III) is 1:1.1.
[0012] In another embodiment, the reaction mixture is heated at
20.degree. C.
[0013] In another embodiment, the reaction mixture is heated for 5
hours.
[0014] In another embodiment, the eluent is petroleum ether: ethyl
acetate=1:1.
[0015] In another embodiment, a method of preparing the compound of
formula (I) includes reacting a compound of formula (II) with a
compound of formula (IV) to obtain the compound of formula (I):
##STR00004##
[0016] In another embodiment, the reaction of the compound of
formula (II) with the compound of formula (IV) comprises the
following steps: placing the compound of formula (II), a catalyst,
and an ionic liquid in a reactor under nitrogen atmosphere, the
catalyst being 12-molybdosilicic acid hydrate
(H.sub.6Mo.sub.12O.sub.41Si); adding the compound of formula (IV)
to the reactor to form a reaction mixture; heating the reaction
mixture at 20-40.degree. C. for 2-5 hours; placing the reaction
mixture in a separating funnel to separate a crude product;
purifying the crude product by recrystallization in methanol to
obtain the compound of formula (I); and recycling the ionic
liquid.
[0017] In another embodiment, the ionic liquid is
1-octyl-3-methylimidazo-lium hexafluorophosphate,
1-hexyl-3-methylimidazolium tetrafluoroborate, or
1-butyl-3-methylimidazolium tetrafluoroborate.
[0018] In another embodiment, the ionic liquid is the ionic liquid
is 1-octyl-3-methylimidazo-lium hexafluorophosphate
(C.sub.8H.sub.15F.sub.6N.sub.2P).
[0019] In another embodiment, the compound of formula (II) and the
compound (IV) have a molar ratio of 1:1 to 1:1.3.
[0020] In another embodiment, the molar ratio of the compound of
formula (II) and the compound of formula (IV) is 1:1.1.
[0021] In another embodiment, the reaction mixture is heated at
25.degree. C.
[0022] In another embodiment, the reaction mixture is heated for 3
hours.
[0023] It is to be understood that both the foregoing general
description and the following detailed description are exemplary
and explanatory and are intended to provide further explanation of
the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The accompanying drawings, which are included to provide a
further understanding of the invention and are incorporated in and
constitute a part of this specification, illustrate embodiments of
the invention and together with the description serve to explain
the principles of the invention.
[0025] In the drawings:
[0026] FIG. 1 shows the in vitro antibacterial activity of
pleuromulin salicylic acid ester against drug-resistant bacteria
MARS 18-171.
[0027] FIG. 2 shows the in vitro antibacterial activity of
pleuromulin salicylic acid ester against drug-resistant bacteria
MARS 18-575.
[0028] FIG. 3 shows the in vitro antibacterial activity of
pleuromulin salicylic acid ester against drug-resistant bacteria
MARS 18-596.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
[0029] Reference will now be made in detail to embodiments of the
present invention, example of which is illustrated in the
accompanying drawings. The following examples illustrate the
present invention, but the present invention is not limited to the
following examples.
EXAMPLE 1
Preparation of Compound of Formula (I)
(2-(((3aR,5S,6S,8R,9R,9aR,12R)-5-hydroxy-6,9,12-trimethyl-1-oxo-6-vinylde-
cahydro-3a,9- propanocyclopenta[8]annulen-8-yl)oxy)-2-oxoethyl
2-hydroxybenzoate)
[0030] In a 100 mL three-necked flask, 246.0 mg (0.65 mmol) of
pleuromulin and 6.1 mg (0.06 mmol) triethylamine were dissolved in
20 mL of dichloromethane under nitrogen atmosphere. 112.3 mg (0.72
mmol) of salicyloyl chloride (compound of formula III) was
dissolved in 10 mL of dichloromethane, and added dropwise to the
reaction mixture by a separatory funnel. After the completion of
the dropwise addition, the reaction mixture was heated at
20.degree. C. for 5 hours. Thin layer chromatography was used to
track the reaction to completion, heating was stopped, and the
protective device was removed. The reaction mixture was
concentrated, washed with water, and extracted with ethyl acetate.
Ethyl acetate was concentrated and dried to obtain a crude product.
The crude product was purified by silica gel column chromatography
with petroleum ether/ethyl acetate=1:1 as eluent, and the eluent
was concentrated under reduced pressure and dried to obtain 221.4
mg of the title compound, a yield of 70.35%.
[0031] .sup.1NMR (400 MHz, chloroform-d) .delta. (ppm): 8.17(1H,
d), 7.97 (1H, d), 7.04 (1H, d), 6.95 (1H, d), 6.55 (1H,d), 6.48
(1H, d), 5.89 (2H, m), 5.34 (2H, d), 4.78 (1H, m), 4.01 (1H, t),
3.42 (1H, t), 2.36 (1H, s), 2.30 (2H, m), 2.19 (2H, m), 1.73-1.40
(9H, m), 1.19 (3H, m), 0.94 (3H, d), 0.79 (3H, m); .sup.13C-NMR
(400 MHz, chloroform-d) .delta. ppm): 216.8, 166.0, 138.8, 136.3,
130.1, 119.4, 117.4, 74.6, 70.6, 58.1, 45.4, 44.7, 44.0, 41.9,
41.5, 36.7, 36.0, 34.4, 30.4, 26.8, 26.3, 24.8, 16.7, 14.8,
11.5.
EXAMPLE 2
Preparation of Compound of Formula (I)
[0032] In a 100 mL three-necked flask, 246.0 mg (0.65 mmol) of
pleuromulin and 6.1 mg (0.06 mmol) triethylamine were dissolved in
20 mL of N,N-dimethylformamide, under nitrogen atmosphere. 112.3 mg
(0.72 mmol) of salicyloyl chloride (compound of formula III) was
dissolved in 10 mL of N,N-dimethylformamide, and added dropwise to
the reaction mixture by a separatory funnel. After the completion
of the dropwise addition, the reaction mixture was heated at
50.degree. C. for 4 hours. Thin layer chromatography was used to
track the reaction to completion, heating was stopped, and the
protective device was removed. The reaction mixture was
concentrated, washed with water, and extracted with ethyl acetate.
Ethyl acetate was concentrated and dried to obtain a crude product.
The crude product was purified by silica gel column chromatography
with petroleum ether/ethyl acetate=2:1 as eluent, and the eluent
was concentrated under reduced pressure and dried to obtain 203.3
mg of the title compound, a yield of 64.58%.
EXAMPLE 3
Preparation of Compound of Formula (I)
[0033] In a 100 mL three-necked flask, 246.0 mg (0.65 mmol) of
pleuromulin and 6.1 mg (0.06 mmol) triethylamine were dissolved in
20 mL of toluene, under nitrogen atmosphere. 121.7 mg (0.78 mmol)
of salicyloyl chloride (compound of formula III) was dissolved in
20 mL of toluene, and added dropwise to the reaction mixture by a
separatory funnel. After the completion of the dropwise addition,
the reaction mixture was heated at 30.degree. C. for 6 hours. Thin
layer chromatography was used to track the reaction to completion,
heating was stopped, and the protective device was removed. The
reaction mixture was concentrated, washed with water, and extracted
with ethyl acetate. Ethyl acetate was concentrated and dried to
obtain a crude product. The crude product was purified by silica
gel column chromatography with petroleum ether/ethyl acetate=1:1 as
eluent, and the eluent was concentrated under reduced pressure and
dried to obtain 210.1 mg of the title compound, a yield of
66.75%.
EXAMPLE 4
Preparation of Compound of Formula (I)
[0034] In a 100 mL three-necked flask, 246.0 mg (0.65 mmol) of
pleuromulin and 6.1 mg (0.06 mmol) triethylamine were dissolved in
20 mL of dichloromethane under nitrogen atmosphere. 132.6 mg (0.85
mmol) of salicyloyl chloride (compound of formula III) was
dissolved in 10 mL of dichloromethane, and added dropwise to the
reaction mixture by a separatory funnel. After the completion of
the dropwise addition, the reaction mixture was heated at
20.degree. C. for 8 hours. Thin layer chromatography was used to
track the reaction to completion, heating was stopped, and the
protective device was removed. The reaction mixture was
concentrated, washed with water, and extracted with ethyl acetate.
Ethyl acetate was concentrated and dried to obtain a crude product.
The crude product was purified by silica gel column chromatography
with petroleum ether/ethyl acetate=1:1 as eluent, and the eluent
was concentrated under reduced pressure and dried to obtain 201.0
mg of the title compound, a yield of 63.85%.
EXAMPLE 5
Preparation of Compound of Formula (I)
[0035] In a 100 mL three-necked flask, 246.0 mg (0.65 mmol) of
pleuromulin and 6.1 mg (0.06 mmol) triethylamine were dissolved in
20 mL of N,N-dimethylformamide, under nitrogen atmosphere. 112.3 mg
(0.72 mmol) of salicyloyl chloride (compound of formula III) was
dissolved in 10 mL of N,N-dimethylformamide, and added dropwise to
the reaction mixture by a separatory funnel. After the completion
of the dropwise addition, the reaction mixture was heated at
40.degree. C. for 7 hours. Thin layer chromatography was used to
track the reaction to completion, heating was stopped, and the
protective device was removed. The reaction mixture was
concentrated, washed with water, and extracted with ethyl acetate.
Ethyl acetate was concentrated and dried to obtain a crude product.
The crude product was purified by silica gel column chromatography
with petroleum ether/ethyl acetate=1:1 as eluent, and the eluent
was concentrated under reduced pressure and dried to obtain 196.9
mg of the title compound, a yield of 62.56%.
EXAMPLE 6
Preparation of Compound of Formula (I)
[0036] In a 100 mL three-necked flask, 246.0 mg (0.65 mmol) of
pleuromulin and 6.1 mg (0.06 mmol) triethylamine were dissolved in
20 mL of dichloromethane under nitrogen atmosphere. 121.7 mg (0.78
mmol) of salicyloyl chloride (compound of formula III) was
dissolved in 10 mL of dichloromethane, and added dropwise to the
reaction mixture by a separatory funnel. After the completion of
the dropwise addition, the reaction mixture was heated at
45.degree. C. for 5 hours. Thin layer chromatography was used to
track the reaction to completion, heating was stopped, and the
protective device was removed. The reaction mixture was
concentrated, washed with water, and extracted with ethyl acetate.
Ethyl acetate was concentrated and dried to obtain a crude product.
The crude product was purified by silica gel column chromatography
with petroleum ether/ethyl acetate=2:1 as eluent, and the eluent
was concentrated under reduced pressure and dried to obtain 194.8
mg of the title compound, a yield of 61.89%.
EXAMPLE 7
Preparation of Compound of Formula (I)
[0037] In a 100 mL three-necked flask, 246.0 mg (0.65 mmol) of
pleuromulin and 6.1 mg (0.06 mmol) triethylamine were dissolved in
20 mL of toluene, under nitrogen atmosphere. 112.3 mg (0.72 mmol)
of salicyloyl chloride (compound of formula III) was dissolved in
20 mL of toluene, and added dropwise to the reaction mixture by a
separatory funnel. After the completion of the dropwise addition,
the reaction mixture was heated at 40.degree. C. for 7 hours. Thin
layer chromatography was used to track the reaction to completion,
heating was stopped, and the protective device was removed. The
reaction mixture was concentrated, washed with water, and extracted
with ethyl acetate. Ethyl acetate was concentrated and dried to
obtain a crude product. The crude product was purified by silica
gel column chromatography with petroleum ether/ethyl acetate=3:1 as
eluent, and the eluent was concentrated under reduced pressure and
dried to obtain 199.7 mg of the title compound, a yield of
63.43%.
EXAMPLE 8
Preparation of Compound of Formula (I)
[0038] In a 100 mL three-necked flask, 246.0 mg (0.65 mmol) of
pleuromulin and 6.1 mg (0.06 mmol) triethylamine were dissolved in
20 mL of dichloromethane under nitrogen atmosphere. 121.7 mg (0.78
mmol) of salicyloyl chloride (compound of formula III) was
dissolved in 10 mL of dichloromethane, and added dropwise to the
reaction mixture by a separatory funnel. After the completion of
the dropwise addition, the reaction mixture was heated at
50.degree. C. for 5 hours. Thin layer chromatography was used to
track the reaction to completion, heating was stopped, and the
protective device was removed. The reaction mixture was
concentrated, washed with water, and extracted with ethyl acetate.
Ethyl acetate was concentrated and dried to obtain a crude product.
The crude product was purified by silica gel column chromatography
with petroleum ether/ethyl acetate=1:1 as eluent, and the eluent
was concentrated under reduced pressure and dried to obtain 210.0
mg of the title compound, a yield of 66.71%.
EXAMPLE 9
Preparation of Compound of Formula (I)
[0039] In a 100 mL three-necked flask, 246.0 mg (0.65 mmol) of
pleuromulin and 6.1 mg (0.06 mmol) triethylamine were dissolved in
20 mL of toluene, under nitrogen atmosphere. 121.7 mg (0.78 mmol)
of salicyloyl chloride (compound of formula III) was dissolved in
20 mL of toluene, and added dropwise to the reaction mixture by a
separatory funnel. After the completion of the dropwise addition,
the reaction mixture was heated at 35.degree. C. for 6 hours. Thin
layer chromatography was used to track the reaction to completion,
heating was stopped, and the protective device was removed. The
reaction mixture was concentrated, washed with water, and extracted
with ethyl acetate. Ethyl acetate was concentrated and dried to
obtain a crude product. The crude product was purified by silica
gel column chromatography with petroleum ether/ethyl acetate=2:1 as
eluent, and the eluent was concentrated under reduced pressure and
dried to obtain 189.4 mg of the title compound, a yield of
60.18%.
EXAMPLE 10
Preparation of Compound of Formula (I)
[0040] In a 100 mL three-necked flask, 246.0 mg (0.65 mmol) of
pleuromulin and 6.1 mg (0.06 mmol) triethylamine were dissolved in
20 mL of toluene, under nitrogen atmosphere. 101.4 mg (0.65 mmol)
of salicyloyl chloride (compound of formula III) was dissolved in
20 mL of toluene, and added dropwise to the reaction mixture by a
separatory funnel. After the completion of the dropwise addition,
the reaction mixture was heated at 20.degree. C. for 7 hours. Thin
layer chromatography was used to track the reaction to completion,
heating was stopped, and the protective device was removed. The
reaction mixture was concentrated, washed with water, and extracted
with ethyl acetate. Ethyl acetate was concentrated and dried to
obtain a crude product. The crude product was purified by silica
gel column chromatography with petroleum ether/ethyl acetate=1:1 as
eluent, and the eluent was concentrated under reduced pressure and
dried to obtain 196.6 mg of the title compound, a yield of
62.45%.
EXAMPLE 11
Preparation of Compound of Formula (I)
[0041] In a 100 mL three-necked flask, 246.0 mg (0.65 mmol) of
pleuromulin and 6.1 mg (0.06 mmol) triethylamine were dissolved in
20 mL of dichloromethane under nitrogen atmosphere. 112.3 mg (0.72
mmol) of salicyloyl chloride (compound of formula III) was
dissolved in 10 mL of dichloromethane, and added dropwise to the
reaction mixture by a separatory funnel. After the completion of
the dropwise addition, the reaction mixture was heated at
35.degree. C. for 4 hours. Thin layer chromatography was used to
track the reaction to completion, heating was stopped, and the
protective device was removed. The reaction mixture was
concentrated, washed with water, and extracted with ethyl acetate.
Ethyl acetate was concentrated and dried to obtain a crude product.
The crude product was purified by silica gel column chromatography
with petroleum ether/ethyl acetate=1:1 as eluent, and the eluent
was concentrated under reduced pressure and dried to obtain 203.2
mg of the title compound, a yield of 64.56%.
EXAMPLE 12
Preparation of Compound of Formula (I)
[0042] In a 100 mL three-necked flask, 246.0 mg (0.65 mmol) of
pleuromulin and 6.1 mg (0.06 mmol) triethylamine were dissolved in
20 mL of dichloromethane under nitrogen atmosphere. 1122.3 mg (0.72
mmol) of salicyloyl chloride (compound of formula III) was
dissolved in 10 mL of dichloromethane, and added dropwise to the
reaction mixture by a separatory funnel. After the completion of
the dropwise addition, the reaction mixture was heated at
30.degree. C. for 6 hours. Thin layer chromatography was used to
track the reaction to completion, heating was stopped, and the
protective device was removed. The reaction mixture was
concentrated, washed with water, and extracted with ethyl acetate.
Ethyl acetate was concentrated and dried to obtain a crude product.
The crude product was purified by silica gel column chromatography
with petroleum ether/ethyl acetate=1:2 as eluent, and the eluent
was concentrated under reduced pressure and dried to obtain 199.9
mg of the title compound, a yield of 63.50%.
EXAMPLE 13
Preparation of Compound of Formula (I)
[0043] In a 250 mL three-necked flask, 246.0 mg (0.65 mmol) of
pleuromulin , 99.4 mg (0.72 mmol) of salicylic acid and 12.0 mg
(0.007 mmol) silicomolybdic acid were dissolved in 100 mL of
1-Butyl-3-methylimidazolium tetrafluoroborate , and nitrogen gas
was added thereto. After full dissolution, the temperature was
raised to 25.degree. C. and the reaction was carried out for 3
hours. Thin layer chromatography was used to track the reaction to
completion, heating was stopped, and the protective device was
removed. The reaction mixture system was allowed to separate into
layers to give a crude pleuromulin salicylic acid ester. The crude
product was recrystallized with 30 mL methanol and dried to obtain
pleuromulin salicylic acid ester. The derivative was 269.7 mg, and
the total yield was 85.69%.
EXAMPLE 14
Preparation of Compound of Formula (I)
[0044] In a 250 mL three-necked flask, 246.0 mg (0.65 mmol) of
pleuromulin, 99.4 mg (0.72 mmol) of salicylic acid and 12.0 mg
(0.007 mmol) silicomolybdic acid were dissolved in 100 mL of
1-butyl-3-methylimidazolium tetrafluoroborate under nitrogen
atmosphere. After full dissolution, the reaction mixture was heated
at 20.degree. C. for 5 hours. Thin layer chromatography was used to
track the reaction to completion, heating was stopped, and the
protective device was removed. The reaction mixture was allowed to
separate into layers to obtain a crude product. The crude product
was recrystallized with 30 mL methanol and dried to obtain 256.6 mg
of the titled compound, a yield of 81.53%.
1-Butyl-3-methylimidazolium tetrafluoroborate was recovered.
EXAMPLE 15
Preparation of Compound of Formula (I)
[0045] In a 250 mL three-necked flask, 246.0 mg (0.65 mmol) of
pleuromulin, 99.4 mg (0.72 mmol) of salicylic acid and 12.0 mg
(0.007 mmol) silicomolybdic acid were dissolved in 100 mL of
1-octyl-3-methylimidazolium hexafluorophosphate under nitrogen
atmosphere. After full dissolution, the reaction mixture was heated
at 40.degree. C. for 4 hours. Thin layer chromatography was used to
track the reaction to completion, heating was stopped, and the
protective device was removed. The reaction mixture was allowed to
separate into layers to obtain a crude product. The crude product
was recrystallized with 30 mL methanol and dried to obtain 250.5 mg
of the titled compound, a yield of 79.58%.
1-Octyl-3-methylimidazolium hexafluorophosphate was recovered.
EXAMPLE 16
Preparation of Compound of Formula (I)
[0046] In a 250 mL three-necked flask, 246.0 mg (0.65 mmol) of
pleuromulin, 99.4 mg (0.72 mmol) of salicylic acid and 12.0 mg
(0.007 mmol) silicomolybdic acid were dissolved in 100 mL of
1-hexyl-3-methylimidazolium tetrafluoroborate under nitrogen
atmosphere. After full dissolution, the reaction mixture was heated
at 35.degree. C. for 4 hours. Thin layer chromatography was used to
track the reaction to completion, heating was stopped, and the
protective device was removed. The reaction mixture was allowed to
separate into layers to obtain a crude product. The crude product
was recrystallized with 30 mL methanol and dried to obtain 243.3 mg
of the titled compound, a yield of 77.31%.
1-Hexyl-3-methylimidazolium tetrafluoroborate was recovered.
EXAMPLE 17
Antibacterial Activity Test of the Compounds of the Invention
[0047] The antimicrobial efficacy was determined by a paper
diffusion method drug sensitivity test.
[0048] E Experimental strains: multi-resistant Staphylococcus
aureus 206 (MRSA-206), multi-resistant Staphylococcus aureus 575
(MRSA-575), multi-resistant Staphylococcus aureus 596 (MRSA-596).
The experimental strain was identified by Huashan Hospital
Affiliated to Fudan University (Institute of Antibiotic of Fudan
University).
[0049] Drug sensitive paper: The drug sensitive paper was a special
drug sensitive paper with a diameter of 6.35 mm and a water
absorption of 0.02 mL. The control drug was vancomycin (30
.mu.g/tablet); the test drugs were pleuromulin (30 .mu.g/tablet),
salicylic acid (30 .mu.g/tablet) and pleuromulin salicylic acid
ester (30 m/tablet).
[0050] Reagents: LB agar medium, LA broth medium, 0.5% DMSO
solution.
[0051] Equipment: Ultra-clean workbench, high-pressure
sterilization pot, gas bath constant temperature shaking
incubator.
[0052] Preparation of bacterial suspension:
[0053] T The experimental strains were inoculated in non-selective
medium and placed in air at 37 .degree. C. for 24 h. A single
colony that grows well and inoculate it into broth medium was
incubate at 35.degree. C..+-.2.degree. C. for 6 hours, and LA broth
medium was used to calibrate the concentration of the bacterial
solution to 0.5 Mie turbidimetric tube (1.5.times.10.sup.8 CFU/mL).
A bacterial suspension was obtained.
[0054] Paper diffusion method drug sensitivity test:
[0055] LB dry powder was weighed, sterilized at 103.4 Kpa,
121.3.degree. C. high-pressure steam for 15 min, and then placed it
in a 40.degree. C.-50.degree. C. water bath. A sterile empty plate
(inner diameter 9 cm) was placed on the surface of the ultra-clean
table water table, and LB dry powder was poured to the plate. The
thickness of each plate was 3 mm to 4 mm. After the plate was
cooled at room temperature, it was stored in the refrigerator at
2.degree. C.-8.degree. C. A sterile cotton swab was used to dip the
bacterial solution and ti evenly coat the surface of the LB plate 3
times. After inoculation of the bacterial suspension, the LB plate
was dried at room temperature for 3 min to 5 min. Sterile forceps
were used to closely attach the antibacterial drug paper to the
dish. The dish was put upside down and placed in a 37.degree. C.
incubator for 24 h. The results were observed by measuring the
diameter. Taking 0.5% DMSO solution as a negative control, the
antibacterial activity is expressed by the diameter of the
inhibition zone. The inhibition zone .gtoreq.17 mm, sensitive; the
inhibition zone of 15 mm-16 mm, intermediary; the inhibition zone
.ltoreq.14 mm, drug resistance.
[0056] In FIGS. 1-3, pleuromulin salicylic acid ester is
represented by the letter A. FIG. 1 shows the antibacterial effect
of the pleuromulin salicylic acid ester on MRSA-206.
[0057] FIG. 2 shows the antibacterial effect of the pleuromulin
salicylic acid ester on MRSA-575. FIG. 3 shows the antibacterial
effect of the pleuromulin salicylic acid ester on MRSA-596. The
results are shown in Table 1.
TABLE-US-00001 TABLE 1 Experimental results of the zone of
inhibition Zone of inhibition/mm Strain Compound MRSA-171 MRSA-575
MRSA-596 0.5% DMSO 0 0 0 Vancomycin 15 17 23 Pleuromulin 0 0 0
Salicylic acid 0 0 0 Pleuromulin 16 10 26 salicylic acid ester
[0058] The results in FIGS. 1-3 and Table 1 show that the starting
materials pleuromutilin and salicylic acid have no inhibitory
effect on drug-resistant bacteria. Pleuromutilin salicylic acid has
strong inhibitory effects on multi-drug resistant Staphylococcus
aureus 171, 575, 596, and the diameter of bacteriostatic zone
against multidrug resistant Staphylococcus aureus 596 was up to 26
mm. In summary, the pleuromutilin salicylic acid ester of the
present invention can be used as an antibacterial drug candidate
for multi-drug resistant Staphylococcus aureus.
* * * * *