U.S. patent application number 12/055384 was filed with the patent office on 2008-07-24 for novel herbicides and methods for preparation thereof.
This patent application is currently assigned to Nanjing Agricultural University. Invention is credited to Shiguo Chen, Xinbin Dai, Yunfa Dong, Sheng Qiang, Chunlong Yang.
Application Number | 20080176748 12/055384 |
Document ID | / |
Family ID | 36679090 |
Filed Date | 2008-07-24 |
United States Patent
Application |
20080176748 |
Kind Code |
A1 |
Qiang; Sheng ; et
al. |
July 24, 2008 |
NOVEL HERBICIDES AND METHODS FOR PREPARATION THEREOF
Abstract
A series of herbicidal molecules derived from
3-acetyl-4-hydroxy-5-sec-butylpyrroline-2-ketone, a natural
substance, and their potential use in agriculture for weed control.
Through the modification of the 5-sec-butyl hydrocarbon chain and
3-acetyl group and the analysis of their biological functioning,
newly designed molecules are superior to the original compound in
herbicidal activity. These molecules inhibit the photosynthesis of
the plants. The treated plants show significant damage in 24 hours
and die within 3-5 days after the chemical treatment. In addition,
the new molecule has relatively simple structure, they are easy to
make and they have better physical properties. They are
broad-spectrum, high potency herbicides.
Inventors: |
Qiang; Sheng; (Nanjing,
CN) ; Chen; Shiguo; (Nanjing, CN) ; Yang;
Chunlong; (Nanjing, CN) ; Dai; Xinbin;
(Nanjing, CN) ; Dong; Yunfa; (Nanjing,
CN) |
Correspondence
Address: |
MATTHIAS SCHOLL
14781 MEMORIAL DRIVE, SUITE 1319
HOUSTON
TX
77079
US
|
Assignee: |
Nanjing Agricultural
University
Nanjing
CN
Nantong Jiangshan Agrochemical & Chemical Limited Liability
Co., Ltd.
Nantong
CN
|
Family ID: |
36679090 |
Appl. No.: |
12/055384 |
Filed: |
March 26, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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PCT/CN2006/001315 |
Jun 13, 2006 |
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12055384 |
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Current U.S.
Class: |
504/283 ;
548/544 |
Current CPC
Class: |
A01N 43/36 20130101;
C07D 207/38 20130101 |
Class at
Publication: |
504/283 ;
548/544 |
International
Class: |
A01N 43/36 20060101
A01N043/36; C07D 207/36 20060101 C07D207/36 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 26, 2005 |
CN |
200510094521.9 |
Claims
1. A compound represented by the general formula (I), or (II), or a
salt thereof ##STR00021## wherein R.sub.1 independently and at each
occurrence represents H; or --C.sub.kH.sub.2k+1,
--OC.sub.kH.sub.2k+1, --(C.dbd.O)C.sub.kH.sub.2k+1,
--COOC.sub.kH.sub.2k+1, --C.sub.kH.sub.2k-1, --OC.sub.kH.sub.2k-1,
--(C.dbd.O)C.sub.kH.sub.2k-1, or --COOC.sub.kH.sub.2k-1, each
unsubstituted or substituted by one or more substituents selected
from a heterocycle, an aryl, a phenylalkyl, a heterocycloalkyl
phenyl, a heterocycloalkyl, a heterocycloalkoxyl, a phenoxyl; a
phenoxy phenyl; a halogen, a cyano, a nitro, an alkoxyalkyl, an
alkoxycarbonyl, and/or an amido; R.sub.2, and R.sub.3 each
independently and at each occurrence represent H,
C.sub.nH.sub.2n+1, C.sub.nH.sub.2n-1, a halogen, --CN, a phenyl, a
halogenated alkyl, a cyano-alkyl, a phenylalkyl, a halogenoalkenyl,
a cyanoalkenyl, or a phenylalkenyl; k represents an integer from 1
to 8; and n represent an integer from 1 to 15.
2. A compound of claim 1, represented by the general formula (III),
(IV) or (V) ##STR00022## wherein X independently and at each
occurrence represents H; or --C.sub.mH.sub.2m+1, or
--OC.sub.mH.sub.2m+1, each unsubstituted or substituted by one or
more substituents selected from a heterocyclic alkyl, a
heterocyclic aryl, an aryl, a phenylalkyl, a heterocycloalkyl
phenyl, a heterocycloalkyl, a heterocycloalkoxyl, a phenoxyl; a
phenoxy phenyl; a halogen, a cyano, a nitro, an alkoxyalkyl, an
alkoxycarbonyl, and/or an amido; R.sub.2, and R.sub.3 each
independently and at each occurrence represent H,
C.sub.nH.sub.2n+1, C.sub.nH.sub.2n-1, a halogen, --CN, a phenyl, a
halogenated alkyl, a cyano-alkyl, a phenylalkyl, a halogenoalkenyl,
a cyanoalkenyl, or a phenylalkenyl; and m represents an integer
from 1 to 7.
3. The compound of claim 1, wherein R.sub.2 and R.sub.3 each
independently and at each occurrence represent H, --CH.sub.3,
--C.sub.2H.sub.5, --CH.sub.2CH.sub.2CH.sub.3, --CH(CH.sub.3).sub.2,
--(CH.sub.2).sub.3CH.sub.3, --C(CH.sub.3).sub.3,
--CH.sub.2CH(CH.sub.3)CH.sub.3, --CH(CH.sub.3)CH.sub.2CH.sub.3,
--(CH.sub.2).sub.4CH.sub.3, --CH(CH.sub.3)CH.sub.2CH.sub.2CH.sub.3,
--CH.sub.2CH(CH.sub.3)CH.sub.2CH.sub.3,
--CH.sub.2CH.sub.2CH(CH.sub.3).sub.2, --CH(CH.sub.2CH.sub.3).sub.2,
--C(CH.sub.2).sub.2C.sub.2H.sub.5, --(CH.sub.2).sub.5CH.sub.3,
--CH(CH.sub.3)(CH.sub.2).sub.3CH.sub.3,
--CH.sub.2CH(CH.sub.3)(CH.sub.2).sub.2CH.sub.3,
--CH.sub.2CH.sub.2CH(CH.sub.3)CH.sub.2CH.sub.3,
--(CH.sub.2).sub.3CH(CH.sub.3).sub.2,
--CH(CH.sub.2CH.sub.3)CH.sub.2CH.sub.2CH.sub.3,
--CH.sub.2CH(CH.sub.2CH.sub.3).sub.2,
--C(CH.sub.3).sub.2(CH.sub.2).sub.2CH.sub.3,
--C(CH.sub.3)CH.sub.2CH.sub.3).sub.2, --(CH.sub.2).sub.6CH.sub.3,
--CH(CH.sub.2CH.sub.2CH.sub.3).sub.2,
--CH.sub.2CH.sub.2CH(CH.sub.2CH.sub.3).sub.2,
--CH(CH.sub.2CH.sub.3)(CH.sub.2).sub.3CH.sub.3,
--CH.sub.2CH(CH.sub.2CH.sub.3)CH.sub.2CH.sub.2CH.sub.3,
--CH(CH.sub.3)(CH.sub.2).sub.4CH.sub.3,
--CH.sub.2CH(CH.sub.3)(CH.sub.2).sub.3CH.sub.3,
--(CH.sub.2).sub.2CH(CH.sub.3)(CH.sub.2).sub.2CH.sub.3,
--(CH.sub.2).sub.3CH(CH.sub.3)CH.sub.2CH.sub.3,
--(CH.sub.2).sub.7CH.sub.3,
--CH.sub.2CH(CH.sub.2CH.sub.2CH.sub.3).sub.2,
--CH(CH.sub.2CH.sub.2CH.sub.3)(CH.sub.2).sub.3CH.sub.3,
--CH(CH.sub.3)(CH.sub.2).sub.5CH.sub.3,
--CH.sub.2CH(CH.sub.3)(CH.sub.2).sub.4CH.sub.3,
--(CH.sub.2).sub.2CH(CH.sub.3)(CH.sub.2).sub.3CH.sub.3,
--(CH.sub.2).sub.3CH(CH.sub.3)(CH.sub.2).sub.2CH.sub.3,
--(CH.sub.2).sub.4CH(CH.sub.3)CH.sub.2CH.sub.3,
--CH(CH.sub.2CH.sub.3)(CH.sub.2).sub.4CH.sub.3,
--(CH.sub.2).sub.3CH(CH.sub.2CH.sub.3).sub.2,
--CH.sub.2CH(CH.sub.2CH.sub.3)(CH.sub.2).sub.3CH.sub.3,
--(CH.sub.2).sub.2CH(CH.sub.2CH.sub.3)(CH.sub.2).sub.2CH.sub.3,
--CH.dbd.CH.sub.2, --CH.dbd.CHCH.sub.3, --CH.sub.2CH.dbd.CH.sub.2,
--CH.dbd.CHCH.sub.2CH.sub.3, --CH.sub.2CH.sub.2CH.dbd.CH.sub.2,
--CH.sub.2 CH.dbd.CHCH.sub.3, or --CH.dbd.CH--CH.dbd.CH.sub.2.
4. The compound of claim 1, wherein R.sub.2 and R.sub.3 each
independently and at each occurrence represent --CN or a phenyl
group substituted at positions 1-3 by a substituent selected from:
--CHClCH.sub.3, --CHClCH.sub.2CH.sub.3, --CHClC.sub.3H.sub.7,
--CHClC.sub.4H.sub.9, --CHClC.sub.5H.sub.11, --CHClC.sub.6H.sub.13,
--CHClC.sub.7H.sub.15, --CHFCH.sub.3, --CHFCH.sub.2CH.sub.3,
--CHFC.sub.3H.sub.7, --CHFC.sub.4H.sub.9, --CHFC.sub.5H.sub.11,
--CHFC.sub.6H.sub.13, --CHFC.sub.7H.sub.15, --CHCNCH.sub.3,
--CHCNCH.sub.2CH.sub.3, --CHCNC.sub.3H.sub.7, --CHCNC.sub.4H.sub.9,
--CHCNC.sub.5H.sub.11, --CHCNC.sub.6H.sub.13,
--CHCNC.sub.7H.sub.15, --CH(C.sub.6H.sub.5)CH.sub.3,
--CH(C.sub.6H.sub.5)CH.sub.2CH.sub.3,
--CH(C.sub.6H.sub.5)C.sub.3H.sub.7,
--CH(C.sub.6H.sub.5)C.sub.4H.sub.9,
--CH(C.sub.6H.sub.5)C.sub.5H.sub.11,
--CH(C.sub.6H.sub.5)C.sub.6H.sub.13,
--CH(C.sub.6H.sub.5)C.sub.7H.sub.15, --CHClCH.dbd.CH.sub.2, or
--CHClCH.sub.2CH.dbd.CH.sub.2, or a corresponding isomeric
halogenate.
5. The compound of claim 2, wherein X is CN, a C.sub.1 to C.sub.5
amido, a benzyl, a naphthalenyl, a phenyl, a pyrrolyl, a furyl, a
thiazolyl, a heterocyclic alkyl phenyl; each phenyl or heterocycle
being unsubstituted or substituted by a substituent selected from a
C.sub.1 to C.sub.6 alkyl, a C.sub.1 to C.sub.4 alkoxy, a
halogenated C.sub.1 to C.sub.5 alkyl, a halogen, a C.sub.1 to
C.sub.5 amido, a nitro, a cyano, an alkoxycarbonyl, and/or a
C.sub.1 to C.sub.5 sulfonyl group.
6. The compound of claim 1 being a calcium, a magnesium, a copper,
an iron, a nickel, a sodium, a potassium, a magnesium, a zinc or an
ammonium salt.
7. A method for preparation of a compound of claim 1 comprising the
following steps: (a) reacting an aminoacid of formula: ##STR00023##
with an alcohol under acidic reaction conditions; (b) neutralizing
with sodium ethoxide; and (c) adding a compound of formula
XCOCH.sub.2COY or cyclobutane-1,3-dione in the presence of a sodium
alkoxide, wherein X independently and at each occurrence represents
H; or --C.sub.mH.sub.2m+1, or --OC.sub.mH.sub.2m+1, each
unsubstituted or substituted by one or more substituents selected
from a heterocyclic alkyl, a heterocyclic aryl, an aryl, a
phenylalkyl, a heterocycloalkyl phenyl, a heterocycloalkyl, a
heterocycloalkoxyl, a phenoxyl; a phenoxy phenyl; a halogen, a
cyano, a nitro, an alkoxyalkyl, an alkoxycarbonyl, and/or an amido;
m represents an integer from 1 to 7; and Y is Cl or Br.
8. The method of claim 7, wherein the steps are carried out in situ
without purification of intermediates.
9. A method of eradicating weeds, comprising applying to the weeds
a compound of claim 1.
10. The method of claim 9, wherein the compound is applied in a
solution having a concentration of 10-800 .mu.g of the compound per
1 g of the solution.
11. The method of claim 9, wherein the weeds are broadleaf weeds,
grassy weeds, or sedge weeds.
12. The method of claim 9, wherein the compound is applied under
exposure to sun light.
13. The method of claim 9, wherein said compound inhibits
photosynthesis and metabolism of the plant cell, which causes a
rapid accumulation of large amounts of active oxygen in cells of
the weeds and subsequent death of the cells.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of International Patent
Application No. PCT/CN2006/001315 with an international filing date
of Jun. 13, 2006, designating the United States, now pending, and
further claims priority benefits to Chinese Patent Application No.
200510094521.9 filed Sep. 26, 2005. The contents of the
aforementioned specifications are incorporated herein by
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of Invention
[0003] This invention relates to the application of chemicals and
biochemicals to weed control in agriculture and, more specifically
to pyrrolidineone derivatives of herbicidal tenuazonic acid
(3-acetyl-4-hydroxy-5-tert-butylpyrroline-2-ketone), and to their
use as herbicides.
[0004] 2. Description of the Related Art
[0005] Tenuazonic acid (formula name:
3-acetyl-4-hydroxy-5-sec-butylpyrroline-2-ketone) is a strong
phytotoxin, isolated, purified and identified from metabolites of
Alternaria Alternata by Qiang Sheng et al. It is isolated from the
crude mixture of metabolites by the extraction of the fermentation
fluid. Due to the low yield (0.0005%) and high cost of
fermentation, it is very important to develop a synthetic process.
Through a rational design, more potent compounds can be made that
are also easy to manufacture. Environmentally safe herbicides can
be developed with low toxicity. This is the main direction of the
current herbicide development.
[0006] 3-Acetyl-4-hydroxy-5-tert-butylpyrroline-2-ketone is a
heterocyclic compound containing carbonyl and hydroxyl functional
groups. The lactam that is part of the heterocyclic ring is the
most important functional group. The hydrophobic side chain also
plays an important role in its herbicidal activity.
[0007] The compound is very effective at killing monocotyledon
weeds (such as common crabgrass and barnyardgrass) and
dicotyledonous weeds including Crofton weeds at a concentration of
50 .mu.g/mL. It has the potential to become a biological herbicide
(CN Pat. Appl. No. 200510038263.2; CN Pat. No. 1644046. However,
the low yield and high cost associated with the fermentation
process prevents large-scale production of this compound.
[0008] A1994 patent (WO1994/01401) discloses
3-benzoylpyrrolidine-2,4-dione derivatives and their herbicidal
activity.
[0009] Chinese Pat. No. 1676515A made claims based on the fact that
some triketones inhibit 4-hydroxyphenylpyruvate dioxygenase (HPPD),
which is a key enzyme responsible for biosynthesis of plastoquinone
and .alpha.-tocopherol. If the biosynthesis of plastoquinone and
.alpha.-tocopherol is blocked, it will impact the biosynthesis of
carotenoids. Therefore both HPPD inhibitor and carotenoid
preventing inhibitors have similar function. Taking advantage of
similar structural modification and synthesis, a key characteristic
of this type of compounds is the existence of N-substituent. The
major representative of this type of herbicides is sulfentrazone,
including isoxazole herbicide, and pyridine type herbicides. It is
reported that tenuazonic acid copper salt has a slight inhibition
to HPPD (Meazza et al., 2002). With only hydrogen attached to
nitrogen, no other substituents, it is obvious that
3-acetyl-4-hydroxy-5-tert-butylpyrroline-2-ketone has a totally
different mechanism of action.
[0010] Study on the mechanism of action of
3-acetyl-4-hydroxy-5-tert-butylpyrroline-2-ketone has shown that
the phytotoxin clearly inhibits plant's photosynthesis. Its
inhibition to Hill reaction is much higher than the typical
photosynthetic inhibitor (herbicide), such as
3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU). In addition, there
is no adverse effect to other parts of the cells. The compound
blocks electron flow from Q.sub.A to Q.sub.B in the photosystem II,
but has no effect on the donor of photosystem II, photosystem I and
other parts of chloroplasts, which was the first time such effects
were observed among known phytotoxins produced by fungus Alternaria
alternata.
[0011] It is believed that the toxin interacts with D1 protein by
competing with Q.sub.B for the binding site and thus inhibits the
electron transfer. Therefore, it is an inhibitory phytotoxin of
photosystem II. Based on the discovery of this mechanism, the
molecular structure of tenuazonic acid has heretofore been and new
herbicidal molecules discovered. CN Appl. Nos. 200510094521.9 and
200610038765.X, and CN Pat Pub No CN1752075 disclose certain
compounds and methods of their synthesis.
[0012] Many photosystem II inhibitors have successfully become
commercial herbicides, such as s-triazines, triazinones and
phenols, etc., and have become major players in the field of
herbicides. There are two advantages associated with photosystem II
inhibitors: first, since photosynthesis is a common phenomenon
among plants, and inhibition is specific to the plants, the
toxicity to animals is low, thus this type of herbicides possesses
the characteristics of high efficacy and low toxicity. Secondly,
with the development of transgenic technology, there are 67,700,000
hectares of farm land that grow transgenic crops globally and
greater than 80% of these crops are herbicide-resistant transgenic
(based on Monsanto's 2003 data).
[0013] The photosynthetic inhibitors herbicides have a growing
share of the herbicides market. With combination of new herbicides
and transgenic agricultural products, the chemical pollution to the
environment has been greatly reduced. Since the photosynthetic
inhibition is the only effect for
3-acetyl-4-hydroxy-5-sec-butylpyrroline-2-ketone on the plant
cells, this type of herbicide with high potency, quick action,
broad-spectrum, simple structure and easy synthesis will have a
bright future.
[0014] There are many types of photosystem II inhibitors according
to their chemical structures such as ureas, pyridines, triazinones,
pyridazinones, dinitrophenols and cyanophenols, etc. They can be
divided into two main groups such as ureas/triazine and phenol. The
first type (classical photosystem II inhibitors) can be represented
as N--C.dbd.X (X stands for O or N atom, not sulfur atom), i.e.
atrazine, metribuzin, phemedipham, terbutryand,
N-(3,4-dichlorophenyl)-N'-methylurea (DCMU) et al. The second type
is phenolic herbicide, including ioxynil, dinoseb and
2-iodo-4-nitro-6-isobutylphenol, etc.
[0015] The common feature of the second type of herbicide is that
the molecules contain at least one carbonyl oxygen, or a hydroxy
oxygen and a long hydrophobic hydrocarbon side-chain. Most of these
herbicides form a hydrogen bond between the carbonyl hydrogen and
the D1 protein of photosystem II, which enables them to
successfully compete with plastoquinone Q.sub.B (secondary electron
acceptor), thus block electron transfer from Q.sub.A to Q.sub.B,
and lead to the inhibition of photosynthetic process of the
plant.
[0016] Only a small number of herbicides form hydrogen bond between
hydroxyl oxygen and D1 protein and successfully blocking
photosynthetic process. The structure of the hydrophobic
hydrocarbon side-chain (number of carbon and chain length) also
influences herbicidal activity. Obviously, the binding site,
binding manner and possible binding region of herbicides to D1
protein determines the strength of herbicidal activity. Based on
the chemical structure,
3-acetyl-4-hydroxy-5-sec-butylpyrroline-2-ketone belongs to the
group of photosystem II inhibitor (containing N--C.dbd.O). Unlike
the classical herbicides mentioned earlier, there are no literature
reports that describe the mechanism of action of this compound to
photosynthesis. Therefore, it might be a new type of photosystem II
inhibitor.
[0017] 3-Acetyl-4-hydroxy-5-sec-butylpyrroline-2-ketone has
moderate toxicity of 200 mg/kg to rat and moderate level
phytotoxicity, which is acceptable in light of its high biological
activity. However, its toxicity level may be reduced through
modification of its chemical structure.
SUMMARY OF THE INVENTION
[0018] In one embodiment, the invention is directed to compounds
represented by the general formula (I), or (II), or a salt
thereof
##STR00001##
[0019] In a class of this embodiment, R.sub.1 independently and at
each occurrence represents H; or --C.sub.kH.sub.2k+1,
--OC.sub.kH.sub.2k+1, --(C.dbd.O)C.sub.kH.sub.2k+1,
--COOC.sub.kH.sub.2+1, --C.sub.kH.sub.2k-1, --OC.sub.kH.sub.2k-1,
--(C.dbd.O)C.sub.kH.sub.2k-1, or --COOC.sub.kH.sub.2k-1, each
unsubstituted or substituted by one or more substituents selected
from a heterocycle, an aryl, a phenylalkyl, a heterocycloalkyl
phenyl, a heterocycloalkyl, a heterocycloalkoxyl, a phenoxyl; a
phenoxy phenyl; a halogen, a cyano, a nitro, an alkoxyalkyl, an
alkoxycarbonyl, and/or an amido.
[0020] In another class of this embodiment, R.sub.2, and R.sub.3
each independently and at each occurrence represent H,
C.sub.nH.sub.2n+1, C.sub.nH.sub.2n-1, a halogen, --CN, a phenyl, a
halogenated alkyl, a cyano-alkyl, a phenylalkyl, a halogenoalkenyl,
a cyanoalkenyl, or a phenylalkenyl.
[0021] In another class of this embodiment, R.sub.2 and R.sub.3
each independently and at each occurrence represent H, --CH.sub.3,
--C.sub.2H.sub.5, --CH.sub.2CH.sub.2CH.sub.3, --CH(CH.sub.3).sub.2,
--(CH.sub.2).sub.3CH.sub.3, --C(CH.sub.3).sub.3,
--CH.sub.2CH(CH.sub.3)CH.sub.3, --CH(CH.sub.3)CH.sub.2CH.sub.3,
--(CH.sub.2).sub.4CH.sub.3, --CH(CH.sub.3)CH.sub.2CH.sub.2CH.sub.3,
--CH.sub.2CH(CH.sub.3)CH.sub.2CH.sub.3,
--CH.sub.2CH.sub.2CH(CH.sub.3).sub.2, --CH(CH.sub.2CH.sub.3).sub.2,
--C(CH.sub.2).sub.2C.sub.2H.sub.5, --(CH.sub.2).sub.5CH.sub.3,
--CH(CH.sub.3)(CH.sub.2).sub.3CH.sub.3,
--CH.sub.2CH(CH.sub.3)(CH.sub.2).sub.2CH.sub.3,
--CH.sub.2CH.sub.2CH(CH.sub.3)CH.sub.2CH.sub.3,
--(CH.sub.2).sub.3CH(CH.sub.3).sub.2,
--CH(CH.sub.2CH.sub.3)CH.sub.2CH.sub.2CH.sub.3,
--CH.sub.2CH(CH.sub.2CH.sub.3).sub.2,
--C(CH.sub.3).sub.2(CH.sub.2).sub.2CH.sub.3,
--C(CH.sub.3)CH.sub.2CH.sub.3).sub.2, --(CH.sub.2).sub.6CH.sub.3,
--CH(CH.sub.2CH.sub.2CH.sub.3).sub.2,
--CH.sub.2CH.sub.2CH(CH.sub.2CH.sub.3).sub.2,
--CH(CH.sub.2CH.sub.3)(CH.sub.2).sub.3CH.sub.3,
--CH.sub.2CH(CH.sub.2CH.sub.3)CH.sub.2CH.sub.2CH.sub.3,
--CH(CH.sub.3)(CH.sub.2).sub.4CH.sub.3,
--CH.sub.2CH(CH.sub.3)(CH.sub.2).sub.3CH.sub.3,
--(CH.sub.2).sub.2CH(CH.sub.3)(CH.sub.2).sub.2CH.sub.3,
--(CH.sub.2).sub.3CH(CH.sub.3)CH.sub.2CH.sub.3,
--(CH.sub.2).sub.7CH.sub.3,
--CH.sub.2CH(CH.sub.2CH.sub.2CH.sub.3).sub.2,
--CH(CH.sub.2CH.sub.2CH.sub.3)(CH.sub.2).sub.3CH.sub.3,
--CH(CH.sub.3)(CH.sub.2).sub.5CH.sub.3,
--CH.sub.2CH(CH.sub.3)(CH.sub.2).sub.4CH.sub.3,
--(CH.sub.2).sub.2CH(CH.sub.3)(CH.sub.2).sub.3CH.sub.3,
--(CH.sub.2).sub.3CH(CH.sub.3)(CH.sub.2).sub.2CH.sub.3,
--(CH.sub.2).sub.4CH(CH.sub.3)CH.sub.2CH.sub.3,
--CH(CH.sub.2CH.sub.3)(CH.sub.2).sub.4CH.sub.3,
--(CH.sub.2).sub.3CH(CH.sub.2CH.sub.3).sub.2,
--CH.sub.2CH(CH.sub.2CH.sub.3)(CH.sub.2).sub.3CH.sub.3,
--(CH.sub.2).sub.2CH(CH.sub.2CH.sub.3)(CH.sub.2).sub.2CH.sub.3,
--CH.dbd.CH.sub.2, --CH.dbd.CHCH.sub.3, --CH.sub.2CH.dbd.CH.sub.2,
--CH.dbd.CHCH.sub.2CH.sub.3, --CH.sub.2CH.sub.2CH.dbd.CH.sub.2,
--CH.sub.2 CH.dbd.CHCH.sub.3, or --CH.dbd.CH--CH.dbd.CH.sub.2.
[0022] In another class of this embodiment, R.sub.2 and R.sub.3
each independently and at each occurrence represent --CN or a
phenyl group substituted at positions 1-3 by a substituent selected
from: --CHClCH.sub.3, --CHClCH.sub.2CH.sub.3, --CHClC.sub.3H.sub.7,
--CHClC.sub.4H.sub.9, --CHClC.sub.5H.sub.11, --CHClC.sub.6H.sub.13,
--CHClC.sub.7H.sub.15, --CHFCH.sub.3, --CHFCH.sub.2CH.sub.3,
--CHFC.sub.3H.sub.7, --CHFC.sub.4H.sub.9, --CHFC.sub.5H.sub.11,
--CHFC.sub.6H.sub.13, --CHFC.sub.7H.sub.15, --CHCNCH.sub.3,
--CHCNCH.sub.2CH.sub.3, --CHCNC.sub.3H.sub.7, --CHCNC.sub.4H.sub.9,
--CHCNC.sub.5H.sub.11, --CHCNC.sub.6H.sub.13,
--CHCNC.sub.7H.sub.15, --CH(C.sub.6H.sub.5)CH.sub.3,
--CH(C.sub.6H.sub.5)CH.sub.2CH.sub.3,
--CH(C.sub.6H.sub.5)C.sub.3H.sub.7,
--CH(C.sub.6H.sub.5)C.sub.4H.sub.9,
--CH(C.sub.6H.sub.5)C.sub.5H.sub.11,
--CH(C.sub.6H.sub.5)C.sub.6H.sub.13,
--CH(C.sub.6H.sub.5)C.sub.7H.sub.15, --CHClCH.dbd.CH.sub.2, or
--CHClCH.sub.2CH.dbd.CH.sub.2, or a corresponding isomeric
halogenate.
[0023] In another class of this embodiment, X is CN, a C.sub.1 to
C.sub.5 amido, a benzyl, a naphthalenyl, a phenyl, a pyrrolyl, a
furyl, a thiazolyl, a heterocyclic alkyl phenyl; each phenyl or
heterocycle being unsubstituted or substituted by a substituent
selected from a C.sub.1 to C.sub.6 alkyl, a C.sub.1 to C.sub.4
alkoxy, a halogenated C.sub.1 to C.sub.5 alkyl, a halogen, a
C.sub.1 to C.sub.5 amido, a nitro, a cyano, an alkoxycarbonyl,
and/or a C.sub.1 to C.sub.5 sulfonyl group.
[0024] In another class of this embodiment, the compounds are
calcium, magnesium, copper, iron, nickel, sodium, potassium,
magnesium, zinc or ammonium salts.
[0025] In another class of this embodiment, k represents an integer
from 1 to 8.
[0026] In another class of this embodiment, n represent an integer
from 1 to 15.
[0027] In another embodiment, the invention is directed to
compounds represented by the general formula (III), (IV) or (V)
##STR00002##
[0028] In a class of this embodiment, X independently and at each
occurrence represents H; or --C.sub.mH.sub.2m+1, or
--OC.sub.mH.sub.2m+, each unsubstituted or substituted by one or
more substituents selected from a heterocyclic alkyl, a
heterocyclic aryl, an aryl, a phenylalkyl, a heterocycloalkyl
phenyl, a heterocycloalkyl, a heterocycloalkoxyl, a phenoxyl; a
phenoxy phenyl; a halogen, a cyano, a nitro, an alkoxyalkyl, an
alkoxycarbonyl, and/or an amido.
[0029] In another class of this embodiment, R.sub.2 and R.sub.3
each independently and at each occurrence represents H,
C.sub.nH.sub.2n+1, C.sub.nH.sub.2n-1, a halogen, --CN, a phenyl, a
halogenated alkyl, a cyano-alkyl, a phenylalkyl, a halogenoalkenyl,
a cyanoalkenyl, or a phenylalkenyl.
[0030] In another class of this embodiment, m represents an integer
from 1 to 7.
[0031] In other aspects, the invention is directed to a method for
preparation of a compound of claim 1 comprising the following
steps: [0032] (a) reacting an aminoacid of formula:
##STR00003##
[0033] with an alcohol under acidic reaction conditions; [0034] (b)
neutralizing with sodium ethoxide; and [0035] (c) adding a compound
of formula XCOCH.sub.2COY or cyclobutane-1,3-dione in the presence
of a sodium alkoxide.
[0036] In a class of this embodiment, X independently and at each
occurrence represents H; or --C.sub.mH.sub.2m+1, or
--OC.sub.mH.sub.2m+1, each unsubstituted or substituted by one or
more substituents selected from a heterocyclic alkyl, a
heterocyclic aryl, an aryl, a phenylalkyl, a heterocycloalkyl
phenyl, a heterocycloalkyl, a heterocycloalkoxyl, a phenoxyl; a
phenoxy phenyl; a halogen, a cyano, a nitro, an alkoxyalkyl, an
alkoxycarbonyl, and/or an amido.
[0037] In another class of this embodiment, m represents an integer
from 1 to 7.
[0038] In another class of this embodiment, Y is Cl or Br.
[0039] In another class of this embodiment, the steps are carried
out in situ without purification of intermediates.
[0040] In other aspects, the invention is directed to a method of
eradicating weeds, comprising applying to the weeds compounds
described herein.
[0041] In a class of this embodiment, the compound is applied in a
solution having a concentration of between 10 and 800 .mu.g of the
compound per 1 g of the solution.
[0042] In another class of this embodiment, the weeds are broadleaf
plants, grassy weeds, or sedge weeds.
[0043] In another class of this embodiment, the compound is applied
under exposure to sun light.
[0044] In another class of this embodiment, the compound inhibits
photosynthesis and metabolism of the plant cell, which causes a
rapid accumulation of large amounts of reactive oxygen species in
cells of the weeds and subsequent death of the cells.
DETAILED DESCRIPTION OF THE INVENTION
[0045] This invention provides a pyrrolidineone-type herbicide,
which was developed through a modification of tenuazonic acid, a
patented herbicidal compound (chemical name:
3-acetyl-4-hydroxy-5-sec-butylpyrroline-2-ketone). The modification
provided us a quick and effective way of developing the new
herbicides.
[0046] It was decided to keep the major functional carbonyl group
of 3-acetyl-4-hydroxy-5-sec-butylpyrroline-2-ketone and modify the
hydrophobic 5-sec-butyl chain and the 3-acetyl group. A large
number of derivatives were synthesized using phosphorous ylides and
halogenated amino acids as precursors. Recently, a new synthetic
route was developed, which no longer uses phosphor ylides and
halogenated amino acids as starting materials. The new process
starts from an amino acid and the 4 step reaction sequence is
carried out in one pot without isolation and purification of any
intermediates.
[0047] The synthetic pathway is as follows:
##STR00004##
[0048] wherein
[0049] X.dbd.H; --C.sub.mH.sub.2m+1 substituted or unsubstituted;
--OC.sub.mH.sub.2m+1 substituted or unsubstituted;
--C.sub.mH.sub.2m-1 substituted or unsubstituted,
--OC.sub.mH.sub.2m-1 substituted or unsubstituted; a substituted
heterocyclic, an aryl, a phenylalkyl, a heterocycloalkyl-phenyl, a
heterocycloalkyl, a heterocycloalkoxy, a phenoxy, or a
phenoxyphenyl; the substituent groups being a halogen, a cyano, a
nitro, an alkyoxyalkyl, an alkyoxycarbonyl, and/or an amido;
[0050] m represents from 1 to 7 carbon atoms; and
[0051] R.sub.2, and R.sub.3 each independently and at each
occurrence represent H, --CH.sub.3, --C.sub.2H.sub.5,
--CH.sub.2CH.sub.2CH.sub.3, --CH(CH.sub.3).sub.2,
--(CH.sub.2).sub.3CH.sub.3, --C(CH.sub.3).sub.3,
--CH.sub.2CH(CH.sub.3)CH.sub.3, --CH(CH.sub.3)CH.sub.2CH.sub.3,
--(CH.sub.2).sub.4CH.sub.3, --CH(CH.sub.3)CH.sub.2CH.sub.2CH.sub.3,
--CH.sub.2CH(CH.sub.3)CH.sub.2CH.sub.3,
--CH.sub.2CH.sub.2CH(CH.sub.3).sub.2, --CH(CH.sub.2CH.sub.3).sub.2,
--C(CH.sub.2).sub.2C.sub.2H.sub.5, --(CH.sub.2).sub.5CH.sub.3,
--CH(CH.sub.3)(CH.sub.2).sub.3CH.sub.3,
--CH.sub.2CH(CH.sub.3)(CH.sub.2).sub.2CH.sub.3,
--CH.sub.2CH.sub.2CH(CH.sub.3)CH.sub.2CH.sub.3,
--(CH.sub.2).sub.3CH(CH.sub.3).sub.2,
--CH(CH.sub.2CH.sub.3)CH.sub.2CH.sub.2CH.sub.3,
--CH.sub.2CH(CH.sub.2CH.sub.3).sub.2,
--C(CH.sub.3).sub.2(CH.sub.2).sub.2CH.sub.3,
--C(CH.sub.3)CH.sub.2CH.sub.3).sub.2, --(CH.sub.2).sub.6CH.sub.3,
--CH(CH.sub.2CH.sub.2CH.sub.3).sub.2,
--CH.sub.2CH.sub.2CH(CH.sub.2CH.sub.3).sub.2,
--CH(CH.sub.2CH.sub.3)(CH.sub.2).sub.3CH.sub.3,
--CH.sub.2CH(CH.sub.2CH.sub.3)CH.sub.2CH.sub.2CH.sub.3,
--CH(CH.sub.3)(CH.sub.2).sub.4CH.sub.3,
--CH.sub.2CH(CH.sub.3)(CH.sub.2).sub.3CH.sub.3,
--(CH.sub.2).sub.2CH(CH.sub.3)(CH.sub.2).sub.2CH.sub.3,
--(CH.sub.2).sub.3CH(CH.sub.3)CH.sub.2CH.sub.3,
--(CH.sub.2).sub.7CH.sub.3,
--CH.sub.2CH(CH.sub.2CH.sub.2CH.sub.3).sub.2,
--CH(CH.sub.2CH.sub.2CH.sub.3)(CH.sub.2).sub.3CH.sub.3,
--CH(CH.sub.3)(CH.sub.2).sub.5CH.sub.3,
--CH.sub.2CH(CH.sub.3)(CH.sub.2).sub.4CH.sub.3,
--(CH.sub.2).sub.2CH(CH.sub.3)(CH.sub.2).sub.3CH.sub.3,
--(CH.sub.2).sub.3CH(CH.sub.3)(CH.sub.2).sub.2CH.sub.3,
--(CH.sub.2).sub.4CH(CH.sub.3)CH.sub.2CH.sub.3,
--CH(CH.sub.2CH.sub.3)(CH.sub.2).sub.4CH.sub.3,
--(CH.sub.2).sub.3CH(CH.sub.2CH.sub.3).sub.2,
--CH.sub.2CH(CH.sub.2CH.sub.3)(CH.sub.2).sub.3CH.sub.3,
--(CH.sub.2).sub.2CH(CH.sub.2CH.sub.3)(CH.sub.2).sub.2CH.sub.3,
--CH.dbd.CH.sub.2, --CH.dbd.CHCH.sub.3, --CH.sub.2CH.dbd.CH.sub.2,
--CH.dbd.CHCH.sub.2CH.sub.3, --CH.sub.2CH.sub.2CH.dbd.CH.sub.2,
--CH.sub.2 CH.dbd.CHCH.sub.3, --CH.dbd.CH--CH.dbd.CH.sub.2, --CN,
phenyl, --CHClCH.sub.3, --CHClCH.sub.2CH.sub.3,
--CHClC.sub.3H.sub.7, --CHClC.sub.4H.sub.9, --CHClC.sub.5H.sub.11,
--CHClC.sub.6H.sub.13, --CHClC.sub.7H.sub.15, --CHFCH.sub.3,
--CHFCH.sub.2CH.sub.3, --CHFC.sub.3H.sub.7, --CHFC.sub.4H.sub.9,
--CHFC.sub.5H.sub.11, --CHFC.sub.6H.sub.13, --CHFC.sub.7H.sub.15,
--CHCNCH.sub.3, --CHCNCH.sub.2CH.sub.3, --CHCNC.sub.3H.sub.7,
--CHCNC.sub.4H.sub.9, --CHCNC.sub.5H.sub.11, --CHCNC.sub.6H.sub.13,
--CHCNC.sub.7H.sub.15, --CH(C.sub.6H.sub.5)CH.sub.3,
--CH(C.sub.6H.sub.5)CH.sub.2CH.sub.3,
--CH(C.sub.6H.sub.5)C.sub.3H.sub.7,
--CH(C.sub.6H.sub.5)C.sub.4H.sub.9,
--CH(C.sub.6H.sub.5)C.sub.5H.sub.11,
--CH(C.sub.6H.sub.5)C.sub.6H.sub.13,
--CH(C.sub.6H.sub.5)C.sub.7H.sub.15, --CHClCH.dbd.CH.sub.2, or
--CHClCH.sub.2CH.dbd.CH.sub.2.
[0052] When X is a methyl group, the following synthetic method can
also be used:
##STR00005##
[0053] 3-Acetyl-4-hydroxy-5-sec-butylpyrroline-2-ketone analogs
were dissolved in a small amount of methanol and diluted with water
to a concentration of 5-100 .mu.g/g. A pathogenic test was
conducted by placing the toxic liquid on the slightly wounded leaf
of Crofton weed with a needle. The test has shown that the
pathogenic capability of
3-Acetyl-4-hydroxy-5-sec-butylpyrroline-2-ketone analogs with
respect to Crofton weed increases with the increase of
concentration. The spot diameter caused on the leaf of Crofton weed
after 24 hours was 2 mm at 50 .mu.g/g.
[0054] The mechanism of action of
3-acetyl-4-hydroxy-5-sec-butylpyrroline-2-ketone analogs on weeds
is the effect on plant photosynthesis; significantly reducing the
photosynthetic oxygen evolution rate and the apparent quantum
efficiency. The main action site of the compounds is the thylakoid
membrane, inhibiting the electron transfer reaction of two
photosystems, especially photosystem II, but no effect has been
observed on the structure and synthesis of the membrane protein. In
addition, the active oxygen content significantly increased 3 hours
after the leaf was treated with
3-acetyl-4-hydroxy-5-sec-butylpyrroline-2-ketone analogs. This may
be the cause of cell death and appearance of the brown spots on the
leaf. Moreover, it may also block the synthesis of protein in the
ribosome.
[0055] The main advantages and positive effects of the invention
include: modification of
3-acetyl-4-hydroxy-5-sec-butylpyrroline-2-ketone was carried out,
based on (1): its inhibitory activity to photosystem II and its
binding mode to D1 protein; and (2): its inhibitory activity and
its action sites, combined with chemical synthetic route of
3-acetyl-4-hydroxy-5-sec-butylpyrroline-2-ketone. Focus was placed
on the carbonyl oxygen (a few hydroxyl oxygens), which played
essential role in the protein binding. The structure of D1 protein
from algae was carefully analyzed and of various factors including
hydrophobicity, electronegativity and stereo hindrance were
considered when designing and selecting the target molecules. It is
obvious that such rational design has advantage over the
traditional chemical herbicide screening.
[0056] A series of herbicidal molecules was prepared through the
modification of 3-acetyl-4-hydroxy-5-sec-butylpyrroline-2-ketone, a
metabolic phytotoxin of Alternaria alternata. These compounds kill
weeds quickly; the weeds treated with the herbicidal agents clearly
show symptoms after 24 hours, and the weeds can be killed in about
3 to 5 days.
[0057] The method of biocontrolling weeds using the analogues of
tenuazonic acid and their salts effectively controls and eradicates
the main gramineous weeds in the farmland, such as common
crabgrass, barnyardgrass, goosegrass, green foxtail, equal
alopecurus, Japanese alopecurus, Beckmannia syzigachne Fern, wild
oat, annual bluegrass, keng stiffgrass, common polypogon, and
rabbitfoot polypogon; broad leaf weeds, such as Crofton weed,
Copperleaf, Yerbadetajo, Redroot pigweed, Tender catchweed
bedstraw, Narrowleaf vetch, Sheathed monochoria, Indian rotala,
Water ammannia, Purslane, Flixweed tansymustard, Shepherdspurse,
Common dayflower, Wild cress, Wormseed mustard, Pennsylvania
bittercress, Geminate speedwell, Mouse-ear chickweed; and sedges,
such as Needle spikesedge, Difformed galingale, Rice galingale, and
Dichotomous dimbristylis.
[0058] The compounds of the invention have high activity at
concentration as low as from 5 to 50 .mu.g/g. At a concentration of
10 to 800 .mu.g/g (close to 45-360 g/hectare), the compounds can
kill a variety of broad-leaf weeds, grassy weeds and sedge weeds.
They are highly potential herbicides.
[0059] The analogues disclosed herein have comparable herbicidal
activity to the original tenuazonic acid. These molecules are easy
to make, thus reducing the manufacturing cost. Because these
compounds were obtained through modification of the metabolite of a
fungus, a natural product, these analogs have some desirable
characteristics of bio-based herbicides: low pollution, few
byproducts, high rate of decomposition and high environmental
safety.
[0060] The new synthetic process can be carried out in one pot
without isolation and purification of the intermediates. This
process can reduce the manufacturing cost.
EXAMPLES
[0061] The following examples illustrate the products of this
invention and the methods for preparing them. However, the examples
are not intended in any way to otherwise limit the scope of the
invention. The number of compounds that were synthesized and
evaluated is far exceeding the number of examples.
Example 1
[0062] List of compounds having formula (I) and (II) (Table 1) and
their herbicidal activities (Table 2).
[0063] Synthesis of compound 1: A 100 mL three-neck flask was
charged with anhydrous alcohol (30 mL), hydrogen chloride (0.055
mol, 2 g) and Isoleucine (0.05 mol, 6.56 g). The mixture was heated
to reflux and stirred for 3 h and then left overnight. Ethanol was
removed by distillation and the residue was mixed with sodium
ethoxide (0.05 mol, 2.6 g, freshly prepared) solution in ethanol.
The mixture was stirred for 0.5 h. Cyclobutane-1,3-dione (0.055
mol, 4.62 g) was added over 1 h, with the temperature kept below
10.degree. C., and the reaction was stirred for 2 h. Benzene (20
ml) and sodium ethoxide (0.0575 mol, 3 g, freshly prepared)
solution in ethanol were added, and the mixture was stirred at
reflux for 3 h and allowed to stand at room temperature overnight.
The reaction mixture was poured into 30 mL of water and acidified
with 10% sulfuric acid (0.055 mol, 55 g), then extracted with ethyl
acetate and dried over sodium sulfate. Ethyl acetate was removed
under vacuum and the residue was mixed with concentrated sulfuric
acid and toluene. The mixture was refluxed in toluene for 2 h.
Compound 1 was obtained as a brown solid after column
chromatography in a 55.6% yield.
[0064] Synthesis of compound 9: A 100 mL three-neck flask was
charged with anhydrous alcohol (30 mL), hydrogen chloride (0.055
mol, 2 g) and Isoleucine (0.05 mol, 6.56 g). The mixture was heated
to reflux and stirred for 3 h and then left overnight. Ethanol was
removed by distillation and the residue was mixed with sodium
ethoxide (0.05 mol, 2.6 g, freshly prepared) solution in ethanol
and stirred for 0.5 h. 2-Propionamidoacetyl chloride (0.055 mol,
8.22 g) was added over 1 h and the reaction was stirred for 2 h.
Benzene (20 ml) and sodium ethoxide (0.0575 mol, 3 g, freshly
prepared) solutions were added, and the mixture was stirred at
reflux for 3 h and allowed to stand at room temperature overnight.
The reaction mixture was poured into 30 mL of water and acidified
with 10% sulfuric acid (0.055 mol, 55 g), then extracted with ethyl
acetate and dried over sodium sulfate. Removal of ethyl acetate
under vacuum gave crude product which was purified with column
chromatography, providing compound 9 as a pale brown oil in a 47.1%
yield.
TABLE-US-00001 TABLE 1 Physical properties of
3-acetyl-4-hydroxy-5-sec-butylpyrroline-2-ketone analogs with
formula (I) and (II) Com- pound Type R.sub.1 R.sub.2 R.sub.3
Appearance 1 II H sec-C.sub.4H.sub.9 H Brown solid 2 II H
C.sub.3H.sub.7CHCl H Brown solid 3 I H sec-C.sub.4H.sub.9 H Light
brown viscous liquid 4 I CH.sub.3CH.sub.2 sec-C.sub.4H.sub.9 H
Light brown viscous liquid 5 I C.sub.2H.sub.5O sec-C.sub.4H.sub.9 H
Light brown viscous liquid 6 I C.sub.6H.sub.5CH.sub.2CH.sub.2
sec-C.sub.4H.sub.9 H Light brown viscous liquid 7 I
NH.sub.2COCH.sub.3CH.sub.2 sec-C.sub.4H.sub.9 H Light brown viscous
liquid 8 I Cl(CH.sub.2).sub.3NH sec-C.sub.4H.sub.9 H Light brown
viscous liquid 9 I C.sub.2H.sub.5CONH sec-C.sub.4H.sub.9 H Light
brown viscous liquid
TABLE-US-00002 TABLE 2 Comparison of the toxicity of
3-acetyl-4-hydroxy-5-sec- butylpyrroline-2-ketone analogs with
formula (I) and (II) Time of disease spot Average diameter of
Treatment to occur (h) the spot after 24 h (mm) Water control /
0.23 .+-. 0.02 Methanol / 0.27 .+-. 0.14 control 1 22.3 .+-. 0.77
1.97 .+-. 0.04 2 22.0 .+-. 2.30 2.96 .+-. 0.01 3 20.9 .+-. 1.01
2.31 .+-. 0.09 4 18.5 .+-. 1.55 2.97 .+-. 0.01 5 20.7 .+-. 0.75
2.35 .+-. 0.14 6 21.2 .+-. 3.85 2.12 .+-. 0.08 7 14.9 .+-. 2.65
4.45 .+-. 0.22 8 20.0 .+-. 1.51 2.53 .+-. 0.18 9 21.9 .+-. 2.00
2.80 .+-. 0.33
Example 2
[0065] Herbicidal activity evaluation of compounds 10-57 with
formula (III), (IV) and (V) (Table 3).
[0066] Synthesis of compound 24: A100 mL three-neck flask was
charged with anhydrous alcohol (30 mL), hydrogen chloride (0.055
mol, 2 g) and 2-amino-2-methylbutanoic acid (0.05 mol, 5.85 g). The
mixture was heated to reflux and stirred for 3 h and then left for
overnight. Ethanol was removed by distillation and the residue was
mixed with sodium ethoxide (0.05 mol, 2.6 g, freshly prepared)
solution in ethanol and stirred for 0.5 h. Cyclobutane-1,3-dione
(0.055 mol, 4.62 g) was added over 1 h maintaining the temperature
of the reaction mixture below 10.degree. C., and the reaction was
stirred for 2 h. Benzene (20 ml) and sodium ethoxide (0.0575 mol, 3
g, freshly prepared) solution in ethanol were added, and the
mixture was stirred at reflux and then allowed to stand for 3 h at
room temperature overnight. The reaction mixture was mixed with 30
mL of water and acidified with 10% sulfuric acid (0.055 mol, 55 g),
then extracted with ethyl acetate and dried over sodium sulfate.
Removal of ethyl acetate under vacuum gave crude product, which was
purified with column chromatography, providing compound 24 as a
pale brown oil in a 53% yield.
[0067] Synthesis of Compound 53: A 100 mL of three-neck flask was
charged with anhydrous alcohol (30 mL), hydrogen chloride (0.055
mol, 2 g) and 2-amino-3-cyanohexanoic acid (0.05 mol, 7.81 g). The
mixture was heated to reflux and stirred for 3 h and then left
overnight. Ethanol was removed by distillation and the residue was
mixed with sodium ethoxide (0.05 mol, 2.6 g, freshly prepared)
solution in ethanol, and stirred for 0.5 h. Cyclobutane-1,3-dione
(0.055 mol, 4.62 g) was added over 1 h and maintaining the
temperature of the reaction mixture below 10.degree. C., and the
reaction was stirred for 2 h. Benzene (20 mL) and sodium ethoxide
(0.0575 mol, 3 g, freshly prepared) solution in ethanol were added,
and the mixture was stirred at reflux for 3 h and then to allowed
to stand at room temperature overnight. The reaction mixture was
mixed with 30 mL of water and acidified with 10% sulfuric acid
(0.055 mol, 55 g), extracted with ethyl acetate and dried over
sodium sulfate. Removal of ethyl acetate under vacuum gave crude
product, which was purified with column chromatography, providing
compound 53 as a brown oil in 45% yield.
TABLE-US-00003 TABLE 3 Physical properties of
3-Acetyl-4-hydroxy-5-sec-butylpyrroline-2-ketone analogues with
formula of (III), (IV) and (V). Com- pound Type X R.sub.2 R.sub.3
Appearance 10 III CH.sub.3 H H Light yellow solid 11 III CH.sub.3
CH.sub.3 H Pale needle crystal 12 III CH.sub.3 CH.sub.3CH.sub.2 H
Light brown solid 13 III CH.sub.3 CH.sub.3CH.sub.2CH.sub.2 H Light
brown viscous liquid 14 III CH.sub.3 n-C.sub.4H.sub.9 H Light brown
viscous liquid 15 III CH.sub.3 n-C.sub.5H.sub.11 H Light brown
viscous liquid 16 III CH.sub.3 n-C.sub.6H.sub.13 H Light brown oil
17 III CH.sub.3 n-C.sub.7H.sub.15 H Light brown oil 18 III CH.sub.3
n-C.sub.8H.sub.17 H Light brown oil 19 III CH.sub.3
C.sub.6H.sub.5CH.sub.2 H Light yellow solid 20 III CH.sub.3
(1-C.sub.6H.sub.5)C.sub.4H.sub.8 H Light yellow solid 21 III
CH.sub.3 H.sub.3C--CH:CH H Brown viscous liquid 22 III CH.sub.3
CH.sub.3 CH.sub.3 Light yellow solid 23 III CH.sub.3
CH.sub.3CH.sub.2 CH.sub.3CH.sub.2 Light brown viscous liquid 24 III
CH.sub.3 CH.sub.3CH.sub.2 CH.sub.3 Light brown viscous liquid 25
III CH.sub.3 CH.sub.3CH.sub.2CH.sub.2 CH.sub.3CH.sub.2CH.sub.2
Light brown viscous liquid 26 III CH.sub.3 CH.sub.3CH.sub.2CH.sub.2
CH.sub.3 Light brown viscous liquid 27 III CH.sub.3
CH.sub.3CH.sub.2CH.sub.2 CH.sub.3CH.sub.2 Light brown viscous
liquid 28 III CH.sub.3 n-C.sub.4H.sub.9 n-C.sub.4H.sub.9 Light
brown viscous liquid 29 III CH.sub.3 n-C.sub.4H.sub.9 CH.sub.3
Light brown viscous liquid 30 III CH.sub.3 n-C.sub.4H.sub.9
CH.sub.3CH.sub.2 Light brown viscous liquid 31 III CH.sub.3
sec-C.sub.5H.sub.11 H Light yellow liquid 32 III CH.sub.3
tert-C.sub.5H.sub.11 H Light yellow liquid 33 III CH.sub.3
iso-C.sub.5H.sub.11 H Light yellow liquid 34 III CH.sub.3
OOCCH.sub.2 H Light yellow solid 35 III CH.sub.3
OOCCH.sub.2CH.sub.2 H Light yellow solid 36 III CH.sub.3
(NH.sub.2)OCCH.sub.2 H Light yellow solid 37 III CH.sub.3
(NH.sub.2)OCCH.sub.2CH.sub.2 H Light yellow solid 38 III CH.sub.3
C.sub.3H.sub.7CHCN H Light brown viscous liquid 39 III CH.sub.3
iso-C.sub.3H.sub.7 H Light brown solid 40 III CH.sub.3
C.sub.3H.sub.7CHCl H Light brown viscous liquid 41 III CH.sub.3
CH.sub.3SCH.sub.2CH.sub.2 H Light brown solid 42 III C.sub.2H.sub.5
sec-C.sub.4H.sub.9 H Light brown viscous liquid 43 III ClC.sub.2H4
sec-C.sub.4H.sub.9 H Light brown viscous liquid 44 III FC.sub.2H4
sec-C.sub.4H.sub.9 H Light brown viscous liquid 45 III
C.sub.2H.sub.5OC.sub.2H.sub.5 sec-C.sub.4H.sub.9 H Light brown
viscous liquid 46 III PhCH.sub.2CH.sub.2O S6C-C.sub.4H.sub.9 H
Light brown viscous liquid 47 III PhOCH.sub.2CH.sub.2
sec-C.sub.4H.sub.9 H Light brown viscous liquid 48 III
(m-diCl)PhCH.sub.2CH.sub.2 sec-C.sub.4H.sub.9 H Light brown viscous
liquid 49 III PhCH.sub.2NH sec-C.sub.4H.sub.9 H Light brown viscous
liquid 50 III THF-CH.sub.2CH.sub.2 sec-C.sub.4H.sub.9 H Light brown
viscous liquid 51 III PhCH.sub.2 sec-C.sub.4H.sub.9 H Light brown
viscous liquid 52 III p-NO.sub.2PhCH.sub.2 sec-C.sub.4H.sub.9 H
Light brown viscous liquid 53 IV CH.sub.3 C.sub.3H.sub.7CHCN H
Brown viscous liquid 54 IV CH.sub.3 C.sub.5H.sub.11CHCN H Brown oil
liquid 55 IV CH.sub.3 C.sub.7H.sub.13CHCN H Brown oil liquid 56 IV
CH.sub.3 C.sub.7H.sub.13CHF H Brown oil liquid 57 V CH.sub.3
CH.sub.3 H Yellow needle crystal
[0068] The study results showed different herbicidal activities of
the above compounds. The different compounds also effect the Hill
reaction rate and fluorescence of the chlorophyll.
Example 3
[0069] 3-Acetyl-4-hydroxy-5-sec-butylpyrroline-2-ketone analogue
(Table 3, compounds 10-57) was dissolved in small amount of
methanol. The solution was then diluted with distilled water to a
concentration of 50 .mu.g/mL. Methanol solution with same
concentration and pure distilled water were used as control of the
experiment. A pathogenic test was conducted by placing the toxic
liquid on the slightly wounded leaf of Crofton weed with a needle.
The experiment was carried out at 25.degree. C. under the natural
light and each test was repeated 6 times. It was measure the
diameter of the spot after 24 h. The experimental results are
listed in Table 4. The data indicated that most of the
3-acetyl-4-hydroxy-5-sec-butylpyrroline-2-ketone analogs have high
herbicidal activity. The size of the side chain also has an effect
on their activity.
TABLE-US-00004 TABLE 4 Comparison of the toxicity of
3-acetyl-4-hydroxy-5-sec- butylpyrroline-2-ketone analogs with
formula (III), (IV), (V) Time of Disease spot Average diameter of
Treatment (h) spot after 24 h (mm) H.sub.2O Control / 0.23 .+-.
0.02 Methanol / 0.27 .+-. 0.14 control 10 29 .+-. 6.30 1.11 .+-.
0.16 11 21.5 .+-. 0 1.80 .+-. 0.41 12 15.2 .+-. 0.35 2.77 .+-. 0.23
13 16.70 .+-. 0.21 5.21 .+-. 0.44 14 13.80 .+-. 0.54 6.37 .+-. 0.04
15 9.5 .+-. 1.26 9.61 .+-. 1.20 16 13.80 .+-. 0.54 7.61 .+-. 0.11
17 9.5 .+-. 2.36 7.94 .+-. 1.30 18 12.00 .+-. 0.48 8.27 .+-. 0.61
19 24 .+-. 4.00 1.24 .+-. 0.10 20 21.1 .+-. 3.56 1.57 .+-. 0.04 21
16.5 .+-. 1.30 2.89 .+-. 0.14 22 20.0 .+-. 1.63 1.76 .+-. 0.24 23
18.3 .+-. 2.17 2.23 .+-. 0.12 24 16.21 .+-. 3.55 2.43 .+-. 0.07 25
15.22 .+-. 2.00 2.44 .+-. 0.10 26 13.61 .+-. 1.35 3.31 .+-. 0.07 27
14.2 .+-. 4.15 3.18 .+-. 0.93 28 16.9 .+-. 2.25 2.40 .+-. 0.11 29
12.1 .+-. 3.75 5.77 .+-. 1.15 30 13.3 .+-. 2.00 4.53 .+-. 1.03 31
10.8 .+-. 2.00 5.93 .+-. 1.35 32 12.5 .+-. 3.75 4.82 .+-. 1.44 33
13.5 .+-. 0.75 4.17 .+-. 1.15 34 24.0 .+-. 0.02 1 .+-. 0.86 35 26.4
.+-. 0.12 1.27 .+-. 0.02 36 21.9 .+-. 0.23 1.54 .+-. 0.07 37 24
.+-. 0.08 1.64 .+-. 0.25 38 13.6 .+-. 0.50 9.82 .+-. 0.02 39 16.5
.+-. 2.15 4.89 .+-. 0.37 40 11.93 .+-. 0.66 8.10 .+-. 0.90 41 20.8
.+-. 3.00 2.45 .+-. 0.24 42 19.4 .+-. 2.50 2.24 .+-. 0.45 43 20.1
.+-. 1.15 2.30 .+-. 0.28 44 12.0 .+-. 1.33 4.07 .+-. 0.51 45 20.3
.+-. 0.57 2.73 .+-. 0.73 46 22.1 .+-. 1.35 2.31 .+-. 0.44 47 21.2
.+-. 1.88 2.12 .+-. 0.09 48 13.5 .+-. 2.77 4.33 .+-. 0.54 49 23.2
.+-. 2.86 2.47 .+-. 0.08 50 22.6 .+-. 0.69 2.66 .+-. 0.46 51 15.1
.+-. 1.82 3.28 .+-. 1.12 52 15.3 .+-. 1.72 3.83 .+-. 1.03 53 12.90
.+-. 0.27 7.334 .+-. 0.845 54 11.30 .+-. 0.73 8.211 .+-. 0.101 55
9.81 .+-. 0.33 8.931 .+-. 0.086 56 14.00 .+-. 1.09 6.927 .+-. 0.317
57 20.4 .+-. 0 1.98 .+-. 0.51
Example 4
[0070] Compounds 1, 2, 3 and 40 were separately dissolved in a
small amount of methanol. The solutions were then diluted with
distilled water to a concentration of 50 .mu.g/mL. A mixture of
methanol and water in the same ratio as the sample solution was
also prepared and used as control in the experiment. The solutions
were sprayed on leaves and stems of three-leaf-stage Crofton weed
seedlings. All the plants were grown in pot in a greenhouse. The
leaves were properly wet by the solutions for consistency and the
treatment was repeated 3 times. The plant damage assessment was
conducted two days later and the results were listed in Table 5.
The measurement of the plant damage was calculated by the formula:
Damage Index=.SIGMA.(damage level.times.number of
plants).times.100/4/number of plants in each treatment. The
calculated results are listed in Table 6.
TABLE-US-00005 TABLE 5 Standard of evaluation of weed damage Damage
Level Description 4 Plant completely dead 3 Two thirds of the plant
stems and leaves dried out 2 Half of the plant stems and leaves
dried out 1 One third of the plant stems and leaves dried out 0 No
damage at all
TABLE-US-00006 TABLE 6 Weed damage assessment results Treatment
Damage Level H.sub.2O control 0 Methanol control 0 1 2 2 2 3 1 40
4
[0071] The data in the Table 6 suggests that the analogs of
3-acetyl-4-hydroxy-5-sec-butylpyrroline-2-ketone have good
herbicidal activity against Crofton weed. Substitution of chlorine
on the side chain increases their activity.
Example 5
[0072] Compound 10-57 were dissolved in small amount of methanol.
The solutions were then diluted with distilled water to a
concentration of 50 .mu.g/mL. A mixture of methanol and water in
the same ratio as the sample solution was also prepared and used as
control in the experiment. The healthy leaves of Crofton weed were
washed in water for 30 minutes and then rinsed with distilled
water. The clean and tissue dried leaves were placed in petri dish
with the back-side of the leaves facing up. Wet filter paper was
also placed in the in petri dish for moisture control. Water,
methanol and chemical solutions of the analogues were applied to
the back-side of each leaf. Test sample was then placed in vacuum
chamber at 25.degree. C. for 15 min followed by exposure to the
strong light (400 .mu.M m.sup.-2 s.sup.-1) for 12 hours. The leaf
sample went through a series of test, and the Hill reaction rate,
the electron transfer activity and fluorescence of chlorophyll were
measured. Four leaves were used for each treatment and each test
was repeated three times.
[0073] The experiment results indicate that compound 10 to 57 can
slow the Hill reaction and inhibit the electron transfer of
photosystem II, but has no effect in photosystem I. As the
experimental data in Table 7 indicated that compounds having
chlorinated side-chain have more inhibitory effect on the activity
of Hill reaction and electron transfer in photosystem II than the
compounds whose side chain are not substituted by halogen.
TABLE-US-00007 TABLE 7 Effects to the photosynthesis of Crofton
weed PSII Activity of Activity of Hill oxygen The t.sub.1/2 of
Reaction evolution of fluorescence Treatment (.mu.MO.sub.2/mgChlh)
(.mu.MO.sub.2/mgChlh) F.sub.v/F.sub.m rise (ms) H.sub.2O control
130.11 65.34 0.83 1339 Methanol 124.38 60.89 0.81 1382 control 1
98.76 50.89 0.82 1184 2 69.41 37.02 0.84 1055 3 62.21 32.14 0.83
1172 4 51.13 28.01 0.83 791 5 52.31 24.10 0.82 826 6 50.04 27.11
0.81 773 7 52.41 29.17 0.82 809 8 49.05 24.65 0.79 725 9 50.12
23.33 0.83 733 10 84.32 47.55 0.79 1176 11 80.00 46.41 0.82 1181 12
70.32 34.54 0.83 925 13 78.19 41.35 0.85 1000 14 67.37 34.01 0.79
910 15 62.77 31.26 0.78 946 16 61.43 30.00 0.83 880 17 57.13 27.04
0.82 917 18 67.27 39.98 0.80 913 19 63.43 40.07 0.79 962 20 57.23
43.40 0.82 876 21 62.34 42.25 0.77 879 22 56.16 38.05 0.82 828 23
63.28 38.24 0.79 855 24 71.37 43.01 0.83 921 25 97.55 57.12 0.82
1197 26 89.15 58.01 0.82 1211 27 91.45 53.24 0.81 1232 28 75.03
31.76 0.82 1124 30 47.33 22.78 0.79 747 32 63.42 32.13 0.82 905 33
51.94 26.54 0.79 791 34 65.73 35.11 0.81 922 38 64.69 40.41 0.81
871 39 62.72 33.79 0.80 884 40 46.20 24.00 0.82 720 41 59.07 41.32
0.83 901 43 63.35 47.80 0.83 880 44 59.15 40.75 0.79 839 45 41.00
27.04 0.79 713 46 58.78 43.67 0.82 899 47 67.99 49.01 0.82 844 51
52.23 32.15 0.81 798 52 53.13 36.86 0.82 814 53 42.72 32.12 0.79
739 54 43.65 31.98 0.81 741 55 42.72 28.63 0.79 727 56 42.72 29.02
0.79 719 57 63.42 35.13 0.82 955
Example 6
[0074] Fourteen salts of
3-acetyl-4-hydroxy-5-sec-butylpyrroline-2-ketone analogs were
dissolved in small amount of methanol and diluted with distilled
water to a concentration of 50 .mu.g/mL. Methanol/water mixture was
also prepared and used as control. Needle puncture method was used
for the test on the small pieces of Crofton weed. Each treatment
was repeated six times or more. The test samples were kept under
natural light at 25.degree. C. for 24 hours. The diameters of
damaged spot of the plant leaves were measured by vernier caliper.
These fourteen compounds are:
(a) Sodium salt of 4-Hydroxy-3-acetyl-pyrroline-2-ketone
##STR00006##
[0075] (b) Sodium salt of
4-Hydroxy-3-acetyl-5-methylpyrroline-2-ketone
##STR00007##
[0076] (c) Sodium salt of
4-Hydroxy-3-acetyl-5-ethylpyrroline-2-ketone
##STR00008##
[0077] (d) Sodium salt of
4-Hydroxy-3-acetyl-5-benzylpyrroline-2-ketone
##STR00009##
[0078] (e) Sodium salt of
4-Hydroxy-3-acetyl-5-propenylpyrroline-2-ketone
##STR00010##
[0079] (f) Potassium salt of
4-Hydroxy-3-acetyl-5-ethylpyrroline-2-ketone
##STR00011##
[0080] (g) Calcium salt of
4-Hydroxy-3-acetyl-5-ethylpyrroline-2-ketone
##STR00012##
[0081] (h) Magnesium (II) salt of
4-Hydroxy-3-acetyl-5-ethylpyrroline-2-ketone
##STR00013##
[0082] (i) Manganese salt of
4-Hydroxy-3-acetyl-5-ethylpyrroline-2-ketone
##STR00014##
[0083] (j) Zinc salt of
4-Hydroxy-3-acetyl-5-ethylpyrroline-2-ketone
##STR00015##
[0084] (k) Iron salt of
4-Hydroxy-3-acetyl-5-ethylpyrroline-2-ketone
##STR00016##
[0085] (l) Copper salt of
4-Hydroxy-3-acetyl-5-ethylpyrroline-2-ketone
##STR00017##
[0086] (m) Sodium salt of
4-Hydroxy-3-acetyl-5-(iso-pentanyl)pyrroline-2-ketone
##STR00018##
[0087] (n) Zinc salt of
4-Hydroxy-3-acetyl-5,5'-dimethylpyrroline-2-ketone
##STR00019##
[0088] (o) Ammonium salt of
4-Hydroxy-3-acetyl-5-ethylpyrroline-2-ketone
##STR00020##
TABLE-US-00008 [0089] TABLE 8 Herbicidal activity of 14 salts to
Crofton weed Average diameter of the damage spot after Treatment
time (h) 24 h (mm) H.sub.2O control / 0.227 .+-. 0.002 Methanol /
0.273 .+-. 0.014 control a 26 .+-. 7.30 1.34 .+-. 0.08 b 19.5 .+-.
0.5 2.21 .+-. 0.18 c 14.5 .+-. 1.8 3.11 .+-. 0.54 d 10.2 .+-. 2.50
5.07 .+-. 0.11 e 16.8 .+-. 1.85 2.42 .+-. 0.05 f 14.2 .+-. 2.00
3.72 .+-. 0.28 g 18.7 .+-. 3.00 2.29 .+-. 0.19 h 17.5 .+-. 1.50
2.88 .+-. 0.10 i 14.3 .+-. 3.15 3.24 .+-. 0.33 j 15.1 .+-. 4.00
2.91 .+-. 0.02 k 17.2 .+-. 0.95 1.72 .+-. 0.15 l 21.6 .+-. 3.05
1.22 .+-. 0.25 m 8.5 .+-. 2.00 8.27 .+-. 1.72 n 18.2 .+-. 2.50 2.63
.+-. 0.06 o 10.3 .+-. 1.50 4.97 .+-. 1.01
[0090] Compared with the no-salt form (data are listed in Table 2
and Table 4), the salt form of these compounds is much more
herbicidal. In addition, the ammonium salt, the sodium salt, the
potassium salt, the magnesium salt and the zinc salt have higher
activity than the calcium, magnesium and copper salts.
Example 7
[0091] Compounds 7, 14, 15, 16, 40, 45, 48 and 53 were dissolved
individually in small amount of methanol, and diluted with
distilled water to concentration of 50 .mu.g/mL. Methanol water
solution and pure water were used as control. A piece of 5 mm leaf
was taken from the second leaf of weed sample and was treated with
the solution three times. 5 pieces of the leaf were prepared for
each treatment. The damage data were collected 4 days later. The
measurement of damage level is described in the Table 9.
TABLE-US-00009 TABLE 9 Standard of evaluation of weed damage Damage
level Description 4 The leaf completely dead 3 Two third of the
leaf withered 2 One half of the leaf withered 1 Only edge of the
leaf withered 0 Not damage at all
[0092] The measurement of the plant damage was calculated by the
formula: Damage Index=.SIGMA.(damage level.times.number of
plants).times.100/4/number of plants in each treatment. The
calculated results are listed in Table 10.
TABLE-US-00010 TABLE 10 Weed damage assessment results Meth- Family
Plant species H.sub.2O anol 7 14 15 16 40 44 48 53 Gramineae
Goosegrass 0 0 4 3 3 3 4 3 3 4 Wild oats 0 0 4 3 3 3 3 3 3 3 Equal
0 0 4 3 3 3 3 3 4 4 alopecurus Japanese 0 0 4 3 3 3 3 4 4 3
alopecurus Keng stiffgrass 0 0 4 3 3 4 3 3 4 4 Common 0 0 3 3 3 3 3
4 4 4 polypogon Green foxtail 0 0 4 3 4 3 3 4 4 3 (Setaria viridis)
Crabgrass 0 0 4 4 4 4 4 4 4 4 (Digitaria sanguinalis) Leptochloa 0
0 4 4 4 4 4 4 4 4 chinensis Barbyardgrass 0 0 4 4 4 4 4 4 4 4
Echinochloa crusgalli Big Bristlegass 0 0 3 2 2 3 3 2 3 3
Amaranthaceae Redroot pigweed 0 0 3 2 2 3 3 2 2 3 (Amaranthus
retroflexus) Alligator weed 0 0 3 3 2 3 3 4 4 3 (Alternanthera
philoxeroides) Pigweed 0 0 3 2 2 2 2 3 3 3 (Amaranthus spinosus)
Malvaceae Malvaceae 0 0 3 2 2 2 2 2 2 3 Abutilon 0 0 2 2 2 3 3 2 3
3 theophrasti Polygonaceae Polygonum 0 0 2 2 2 2 2 2 2 3
lapathifolium Rumex 0 0 2 1 2 2 2 3 2 3 japonicus Polygonum 0 0 3 2
2 3 3 3 3 3 perfoliatum Polygonum 0 0 3 2 2 3 2 3 3 3 hydropiper
Rumex dentatus 0 0 2 2 2 2 2 3 3 2 Euphorbiaceae Acalypha 0 0 3 2 2
2 3 3 3 2 australis Cannabinaceae Humulus 0 0 3 2 2 3 3 2 3 2
scandens Labiatae Perilla 0 0 2 2 3 2 2 3 2 2 frutescens Galeopsis
bifida 0 0 3 2 2 2 3 3 2 3 Lamium 0 0 3 2 3 2 3 3 2 2 amplexicaule
Mosla scabra 0 0 2 2 2 2 2 2 2 2 Scrophulariaceae Veronica 0 0 2 3
2 2 2 3 3 3 didyma Veronica 0 0 3 2 2 2 3 3 3 3 persica
Commelinaceae Commelina 0 0 4 2 2 3 3 2 4 3 communis Commelina 0 0
4 3 3 3 3 3 4 3 bengalensis Convolvulaceae Japanese false 0 0 4 3 3
4 3 4 4 4 bindweed (Calystegia hederacea) Dichondra 0 0 3 2 2 3 3 2
3 2 repens Pharbitis nil 0 0 2 2 3 2 2 3 3 3 Compositae Lapsana 0 0
4 3 2 3 3 3 4 3 apogonoides Xanthium 0 0 3 2 2 2 2 2 3 3 sibiricum
Conyza 0 0 4 3 3 3 3 4 4 3 canadensis Eclipta prostrata 0 0 4 3 4 3
3 4 4 4 Sonchus 0 0 4 3 3 3 3 3 4 4 oleraceus Aster 0 0 4 3 3 4 3 4
4 4 ageratoides var. scaberulus Youngia 0 0 3 3 3 3 3 3 3 4
japonica Sonchus asper 0 0 4 3 3 3 3 3 4 3 Cirsium 0 0 3 3 3 3 3 3
4 4 setosum Erigeron annuus 0 0 3 3 4 3 3 4 4 3 Ambrosia 0 0 3 3 2
3 3 4 3 3 artemisiifolia Carpesium 0 0 3 2 2 2 3 3 4 2 abrotanoides
Eupatorium 0 0 4 3 4 4 4 4 4 4 adenophorum Trifolium 0 0 3 3 3 3 3
4 4 4 pratense Rosaceae Duchesnea 0 0 2 2 3 2 2 3 3 3 indica
Vitaceae Cayratia 0 0 2 2 2 2 2 3 3 3 japonica Parthenocissus 0 0 2
2 3 2 2 3 3 3 tricuspidata Chenopodiaceae Chenopodium 0 0 3 2 2 2 2
3 3 3 serotinum Oxalidaceae Oxalis 0 0 4 4 3 4 4 4 4 4 corniculata
Plantaginaceae Plantago 0 0 3 2 3 2 3 3 2 2 asiatica Cyperaceae
Cyperus 0 0 2 2 2 2 2 2 2 2 rotundus Cyperus 0 0 4 3 3 3 3 3 4 3
difformis Fimbristylis 0 0 3 2 2 3 3 2 3 2 miliacea
[0093] The results listed in the table 10 suggest that eight
compounds (7, 14, 15, 16, 40, 44, 48, and 53) have potential to be
used to control or kill grassy weed such as Common crabgrass,
Bbarnyardgrass, Difformed galingale, broadleaf weeds, Yerbadetajo,
Copperleaf, Chenopodium serotinum, Commelina communis, Alligator
weed, Redroot pigweed, Japanese false bindweed, Sonchus oleraceus
etc.
Example 8
[0094] Compound 1, 2, 3 and 40 were dissolved in small amount of
methanol and diluted with distilled water to concentration of 50
.mu.g/mL. The solution was sprayed to the soil sample until the
soil was wet but not overflows. After standing at room temperature
for 3 hours, the soil sample was washed with water and methanol.
The wash solution was collected and concentrated. Such process was
repeated three times. The concentrated solutions were used for
herbicidal activity test using the method of needle puncture on
Crofton weed. Methanol water solution and pure water were used as
control. The experiment for every sample was repeated six times.
The spot diameters were measured with vernier caliper after the
plant was kept under natural light at 25.degree. C. for 24 hours
(Table 11).
TABLE-US-00011 TABLE 11 Evaluation compound toxicity after they
were treated with soil Average diameter of the spot after 24 h (mm)
Treatment H.sub.2O wash Methanol wash H.sub.2O control 0.234 .+-.
0.045 Methanol 0.288 .+-. 0.024 control 1 0.223 .+-. 0.077 0.292
.+-. 0.041 2 0.280 .+-. 0.030 0.362 .+-. 0.012 3 0.273 .+-. 0.062
0.334 .+-. 0.082 40 0.336 .+-. 0.050 0.416 .+-. 0.024
[0095] Based on data listed in Table 11, it is clear that the
herbicidal activity of all 4 compounds were completely lost after
the soil treatment.
* * * * *