Herbicidal 1-substituted methyl-tetrazolinones

Details Herbicidal 1-substituted methyl-tetrazolinones Herbicidal 1-substituted methyl-tetrazolinones

1999-08-04

2001-07-17

Morris, Patricia L. (Department: 1612)

Organic compounds -- part of the class 532-570 series

Organic compounds

Heterocyclic carbon compounds containing a hetero ring...

Reexamination Certificate

active

06262275

ABSTRACT:

The present invention relates to novel 1-substituted methyltetrazolinones, processes for their preparation and their use as herbicides as well as novel intermediates therefore.
It has already been known that certain tetrazolinones possess herbicidal activity (see EP-A-146,279).
These previously known compounds, however, have not been fully satisfactory in respect of their herbicidal effect and phytotoxicity on crop plants.
Now it has been discovered that novel 1-substituted methyltetrazolinones of the formula (I)
wherein
R
1
represents a 5-membered heterocyclic radical which has 1 to 3 heteroatoms selected arbitrarily from the group consisting of N, O and S and which is optionally substituted by halogen and/or C
1-4
alkyl, or represents oxiran-2-yl, optionally chloro-substituted pyridyl or C
1-4
alkyl-S(O)
m
— wherein m represents 0, 1 or 2, or represents a C
3-6
alicyclic hydrocarbon radical,
R
2
and R
3
represent, independently of one another, C
1-4
alkyl, C
3-7
cycloalkyl or optionally substituted phenyl, or R
2
and R
3
may form, together with the N-atom to which they are bonded, an optionally substituted ring,
R
4
represents a hydrogen atom or methyl, and
n represents 0 or 1
have surprisingly superior activity.
The compounds of the formula (I) according to the invention can be produced, for instance, by the following process in which
process (a):
compounds of the formula (II)
wherein
R
1
, R
4
and n are defined as above,
are reacted with compounds of the formula (III)
wherein
R
2
and R
3
are defined as above, and
M represents a leaving radical such as chloro or bromo,
in the presence of an inert solvent, and if appropriate in the presence of a base.
The compounds of the formula (I) according to the invention have strong herbicidal activity and they exhibit very superior herbicidal action as well as better compatibility with crop plants in comparison to the previously known compounds which are similar to those of the formula (I) described in the above EP-A-146,279.
Therefore, the compounds according to the invention are extremely useful as herbicides.
In this specification, the term “5-membered heterocyclic radical” includes a monovalent radial consisting of a saturated, unsaturated or partially unsaturated 5-membered heterocyclic ring which has 1 to 3 identical or different heteroatoms selected from the group consisting of N, O and S. Preferably, it represents a monovalent radical consisting of an unsaturated 5-membered heterocyclic ring having one or two N atom(s) and one O atom or one S atom; two N atoms; or one S atom or O atom. Specific examples thereof include, for example, isoxazolyl, pyrazolyl, 1,2,5-oxadiazolyl, 1,3,4-oxadiazolyl, thiazolyl, isothiazolyl, thienyl, furyl, imidazolyl, 1,2,3-oxadiazolyl, 1,2,4-oxadiazolyl and 1,3,4-thiadiazolyl.
The term “halogen” includes fluorine, chlorine, bromine and iodine, preferably being fluorine, chlorine or bromine.
The term “C
3-6
alicyclic hydrocarbon radical” refers to a saturated or partially unsaturated alicyclic hydrocarbon radical having 3 to 6 carbon atoms, and includes, for example, cycloalkyl such as cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl; and cycloalkenyl such as cyclopentenyl and cyclohexenyl.
The term “alkyl” refers to an alkyl group which may be straight chain or branched chain, and includes, for example, methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, n-pentyl and n-hexyl.
The term “cycloalkyl” is a cyclic alkyl radical, and includes, for example, cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl.
The substituent(s) for the “optionally substituted phenyl” include, for example, halogen and C
1-4
alkyl. Said phenyl can be substituted by at least 1, preferably 1 to 2 of these substituent(s).
With regard to the phrase “optionally substituted ring which is formed together with the N-atom”, said ring is a 5- to 6-membered monocyclic or benzo-condensed polycyclic heterocyclic ring containing at least 1, preferably only 1 N-atom. Examples of the cyclic rings which may be formed by
in formula (I) include 1,2-dihydroquinolin-1-yl and 1,2,3,4-tetrahydroquinolin-1-yl. These rings may optionally be substituted and the possible substituents include, for example, C
1-4
alkyl such as methyl or ethyl and halogen such as fluoro or chloro, preferably being methyl or fluoro.
Preferred compounds of the formula (I) according to the invention are those wherein
R
1
represents a 5-membered heterocyclic radical which has one or two N atoms and one O atom or one S atom; two N atoms; or one N atom or O atom and which is optionally substituted by chloro and/or methyl, or represents oxiran-2-yl, chloro-substituted pyridyl, C
1-3
alkylthio, methylsulfinyl, methylsufonyl, cyclopropyl, cyclopentenyl or cyclohexyl,
R
2
and R
3
represent, independently of one another, C
1-4
alkyl, C
5-6
cycloalkyl or optionally substituted phenyl (here the substituent(s) being halogen or C
1-4
alkyl), or
R
2
and R
3
may form, together with the N-atom to which they are bonded, optionally substituted 1,2-dihydroquinolin-1-yl or 1,2,3,4-tetrahydroquinolin-1-yl (here the substituent(s) being methyl or fluoro),
R
4
represents a hydrogen atom, and
n represents 0 or 1.
More preferred compounds of the formula (I) according to the invention are those wherein
R
1
represents isooxazolyl, pyrazolyl, 1,2,5-oxadiazolyl, 1,3,4-oxadiazolyl, thiazolyl, isothiazolyl, thienyl or furyl, said radicals optionally being substituted by chloro and/or methyl, or represents oxiran-2-yl, 3-pyridyl, 6-chloro-3-pyridyl, methydtrio, n-propylthio, isopropylthio, methylsulfinyl, methysulfonyl, cyclopropyl, cyclopentenyl or cyclohexyl,
R
2
and R
3
represent, independently of one another, C
1-3
alkyl, cyclohexyl or optionally substituted phenyl (here the substituent(s) being fluoro, chloro, bromo or methyl), or
R
2
and R
3
may form, together with the N-atom to which they are bonded, 6-fluoro-2,2-dimethyl-1,2,3,4-tetrahydroquinolin-1-yl, 2-methyl-1,2,3,4-tetrahydroquinolin-1-yl, 2,2-dimethyl-1,2-dihydroquinolin-1-yl, 6-fluoro-2,2-dimethyl-1,2-dihydroquinolin-1-yl or 2,2-dimethyl-1,2,3,4-tetrahydroquinolin-1-yl,
R
4
represents a hydrogen atom, and
n represents 0 or 1.
The process (a) for the preparation of the compounds of the above formula (I) is represented by the following equation, when, as the starting materials, for example, 1-(3-isooxazolylmethyl)-5(4H)-tetrazolinone and N-isopropyl-N-phenylcarbamoyl chloride are used.
In the above process (a), the compounds of the formula (II) which are used as the starting material are new and can be produced, for instance, by any of the following processes (b) to (f): That is to say by
process (b):
the process of reacting compounds of the formula (IV)
wherein
R
1
, R
4
and n are as defined above, with trimethylsilyl azide in the presence of a catalytic amount of boron trifluoride-ether complex, or
process (c):
the process of reacting the compounds of the above formula (IV) with sodium azide in the presence of a catalytic amount of ammonium chloride in a polar solvent, or
process (d):
the process of reacting compounds of the formula (V)
wherein
R
1
, R
4
and n are as defined above,
with trimethylsilyl azide in the presence of a catalytic amount of boron trifluorideether complex, or
process (e):
the process of reacting compounds of the formula (VI)
wherein
R
1
, R
4
and n are as defined above,
with compounds of the formula (VII)
wherein
M represents a hydrogen atom or methyl, or
process (f): when
R
1
represents a radical other than C
1-4
alkyl-S(O)
m
—, the process of reacting compounds of the formula (VIII)
wherein
R
1′
represents the radical as defined for R
1
, with the exception of C
1-4
alkyl-S(O)
m
—, and
R
4
and n are as defined above,
with sodium periodate in the presence of a catalytic amount of osmium oxide [OsO
4
].
Alternatively, the compounds of the formula (I) wherein R
1
represents alkyl(C
1-4
)sulfinyl or alkyl(C
1-4
)sulfonyl, can be produced by oxidizing the compound wherein R
1
corresponds to alkyl(C
1-4
)thio according t

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