Organic compounds -- part of the class 532-570 series – Organic compounds – Amino nitrogen containing
Reexamination Certificate
2000-08-14
2001-10-30
Kumar, Shailendra (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Amino nitrogen containing
C504S220000, C504S249000, C504S289000, C504S336000, C540S607000, C546S197000, C546S226000, C549S077000, C564S182000
Reexamination Certificate
active
06310246
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to novel fluorovinyloxyacetamides, a process for preparing same and a highly selective and effective herbicidal composition comprising same.
DESCRIPTION OF THE PRIOR ART
Due to the perpetual emergence of weeds resistant to the herbicide in use, there always exists a need to develop a new class of effective herbicides that can protect crops without harming the environment. For example, the sulfonylurea-based herbicides that have been widely used in controlling rice-field weeds for the last two decades have now become less effective, particularly in controlling annual weeds. Accordingly, many attempts have been made to develop new rice-field herbicides of different chemical classes, including those based on amides and carbamates.
There has recently been reported a new class of herbicides based on heteroaryloxyacetamide derivatives (DE Patent No. 2903966; DE Patent No. 3038636; DE Patent No. 3323334; DE Patent No. 3344236; DE Patent No. 3418167; DE Patent No. 3422861; DE Patent No. 440596; WO 95/34560; WO 96/08488; WO 96/11575; WO 96/28434; and WO 97/08160). However, these heteroaryloxyacetamides have limited herbicidal activity against a narrow spectrum of weeds.
SUMMARY OF THE INVENTION
Accordingly, it is a primary object of the present invention to provide a novel compound having superior herbicidal activity against a wide spectrum of weeds.
It is another object of the present invention to provide a process for the preparation of said compound.
It is a further object of the present invention-to provide a herbicidal composition comprising said compound.
In accordance with one aspect of the present invention, there is provided a novel fluorovinyloxyacetamide compound of formula (I):
wherein:
R
1
is a phenyl group optionally having one or more substituents selected from the group consisting of C
1-6
alkyl, halogen-substituted C
1-6
alkyl, C
1-6
alkoxy and halogen;
R
2
is a C
1-6
alkyl group; or
R
1
and R
2
together with the nitrogen atom to which they are bound form a 5-, 6- or 7-membered nitrogen heterocycle optionally having one or more ring oxygen atoms, double bonds and C
1-6
alkyl substituents;
R
3
is a phenyl or thiophen-2-yl group optionally having one or more substituents selected from the group consisting of C
1-6
alkyl, halogen-substituted C
1-6
alkyl, C
1-6
alkoxy, methylenedioxy and halogen; and
R
4
is a perfluoro C
1-6
alkyl group.
DETAILED DESCRIPTION OF THE INVENTION
The compound of formula (I) of the present invention may be in the form of the E isomer of formula (I-a), the Z isomer of formula (I-b), or a mixture thereof:
wherein R
1
, R
2
, R
3
and R
4
have the same meanings as defined in formula (I) above. The two stereoisomers, E and X isomers, are defined according to the terminology of the Cahn-Ingold-Prelog system(J. March,
Advanced organic Chemistry
, 3rd Ed., Wiley-Interscience) which is incorporated herein by way of reference.
Among the compounds of the present invention, preferred are: those wherein R
1
is a phenyl group optionally having a halogen, methyl or methoxy substituent, R
2
is a methyl or ipropyl group, R
3
is a phenyl group optionally substituted with a halogen or methoxy group and R
4
is CF
3
or CF
2
CF
3
; and those wherein R
1
and R
2
together with the nitrogen atom to which they are bound form a piperidino, hexamethyleneimino, morphorino or 1,2,3,6-tetrahydropyridino ring optionally having one or two C
1-2
alkyl substituents, R
3
is a phenyl group optionally substituted with a halogen or methoxy group and R
4
is CF
3
.
The compound of the present invention may be prepared by reacting an alcoholic compound of formula (II) with a fluorovinyl compound of formula (III) in the presence of a base, as shown in Reaction Scheme A:
wherein R
1
, R
2
, R
3
and R
4
have the same meanings as defined in formula (I) above.
An alcoholic compound of formula (II) may be prepared by substitution, acetylation and hydrolysis of an amine of formula (VI) according to a conventional method(Hamm, P. C.,
J. Amer. Chem. Soc
., 78, 2556 (1956); Hartman, W. W. et al.,
Org. Syn., Coll
., 3, 650 (1955); and Brasen, W. R. et al.,
Org. Syn. Coll
., 4, 582 (1963)), as shown in Reaction Scheme B:
wherein R
1
and R
2
have the same meanings as defined in formula (I) above.
A difluorovinyl compound of formula (III) may be prepared form a halogen compound of formula (VIII) by Grignard and Wittig reactions(Herkes, F. E. et al.,
J. Org. Chem
., 32, 1311 (1967); and Wheaton, G. A. et al.,
J. Org. Chem
., 48, 917 (1983)), as shown in Reaction Scheme C:
wherein X is Br or Cl; and R
3
and R
4
have the same meanings as defined in formula (I) above.
As shown in Reaction Scheme A, the fluorovinyloxyacetamide compound of the present invention may be prepared by reacting an alcoholic compound of formula (II) with a fluorovinyl compound of formula (III) in the presence of a base. Each of compounds of formula (II) and (III) may be used in equimolar amounts and the base may be used in one to two equivalent amounts. The base may be an inorganic base, e.g., sodium hydride, potassium hydride, potassium t-butoxide, sodium hydroxide, potassium hydroxide, sodium carbonate or potassium carbonate; or an organic base, e.g., triethylamine or pyridine. The solvent which may be used in the reaction is benzene, toluene, tetrahydrofuran, acetone, acetonitrile, dichloromethane, dimethylformamideor dimethylsulfoxide, individually or combined with water. The reaction may be conducted at a temperature ranging from room temperature to 100° C. The progress of the reaction is conveniently followed by measuring the disappearance of the compound of formula (II) with thin layer chromatography(TLC).
The compound of the present invention is obtained as a mixture of two isomers, i.e., the E and Z isomers.
For example, in the case of the compound of the present invention wherein R
1
is phenyl, R
2
is methyl, R
3
is phenyl and R
4
is CF
3
(Compound 1), a 2:1 mixture of the Z and F isomers is obtained, the isomer ratio being determined on the basis of both
1
H-NMR and
19
F-NMR analysis of the product. Namely, the peak area ratio of the
1
H-NMR peak for the methylene group of the Z isomer(a singlet at 4.30 ppm relative to CHCl
3
) to that of E isomer(a singlet at 4.49 ppm) is about 2:1; and
19
F-NMR analysis(reference compound: CFCl
3
) shows a peak area ratio of about 2:1 when the peaks for the fluorine and CF
3
substituents of the Z isomer(a quartet having a coupling constant of 24.08 Hz at −84.99 ppm and a doublet having a coupling constant of 25.07 Hz at −57.36 ppm, respectively) are compared with those of the E isomer(a quartet having a coupling constant of 12.43 Hz at −83.40 ppm and a doublet having a coupling constant of 12.66 Hz at −57.95 ppm, respectively).
Likewise, the preparation of the compound of the present invention wherein R
1
and R
2
together with the nitrogen atom to which they are attached form a piperidino group, R
3
is phenyl and R
4
is CF
3
(Compound 221) leads to a 2:1 mixture of the Z and E isomers. Namely, the peak area ratio of the 1H-NMR peak for the methylene group of the Z isomer(a singlet at 4.67 ppm) to that of the E isomer(a singlet 4.79 ppm) is about 2:1; and the
19
F-NMR analysis(reference compound: CFCl
3
) shows a peak area ratio of 2:1 when the peaks for the fluorine and CF
3
substituent of the Z isomer(a quartet having a coupling constant of 25.15 Hz at −84.28 ppm and a doublet having a coupling constant of 24.85 Hz at −57.38 ppm, respectively) are compared with those of the E isomer(a quartet having a coupling constant of 12.46 Hz at −82.24 ppm and a doublet having a coupling constant of 12.32 Hz at −57.83 ppm, respectively).
The compound of the present invention has herbicidal activity against a broad spectrum of weeds, in particular, against those belonging to the Gramineae family, e.g., rice(
Oryza sativa
L.), barnyardgrass(
Echinochlora crus
-
galli
8P. BEAUV. var. oryzicola OHWI), bulrush(
Scirpus juncoides
ROXB), um
Hong Kyung-Sik
Kim Bum-Tae
Kwon Yong-Woong
Park Jae-Eup
Park No-Kyun
Korea Research Institute of Chemical Technology
Kumar Shailendra
Roseman & Colin LLP.
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