US3641042A

US3641042A - Nitramino pyridine derivatives

Info

Publication number: US3641042A
Application number: US794783*A
Authority: US
Inventors: Karl Ayad
Original assignee: Monsanto Chemicals Ltd
Current assignee: Monsanto Chemicals Ltd
Priority date: 1968-01-29
Filing date: 1969-01-28
Publication date: 1972-02-08
Anticipated expiration: 1989-02-08
Also published as: GB1219633A

Abstract

HERBICIDAL ACTIVE NITRAMINOPYRIDINES OF THE FORMULA

R,R2,R3,(O2N-NH-)PYRIDINE

OR AN N-OXIDE OR SALT OF SUCH A NITRAMINOPYRIDINE BASE, WHEREIN R IS HYDROGEN OR ALKYL HAVING FROM 1 TO 6 CARBON ATOMS; R2 IS CHLORINE BROMINE, NITRO OR ALKYL HAVING FROM 1 TO 6 CARBON ATOMS; AND R3 IS CHLORINE, BROMINE OR NITRO BUT DIFFERENT FROM R2.

Description

i St tes Peel U.s. Cl. 260296 4 Claims ABSTRACT OF Tl-IE DISCLOSURE Herbicidal active nitraminopyridines of the formula an N-oxideorsalt of such; a nitraminopyridine base, whr ein-R'is hydrogenioralkyl having from 1 to 6 carbon atoms; R isgchlorine,bromine, nitro or alkyl having from l to6 carbonatorns; and R is chlorine, bromine v I v so includes a herbicidal composition comprising a pyridine baseadefined above or an oxide or salt of-j such a 'base,..in .admix t ure with a diluent or carrier and a surface active agent.

.Suitable alkyl groups represented by R and R include metiiyh, ethylf, ist'a giror'n l v t-butyl-, p'entylr, hexyl-, and cyclohexyl.

The various groups-.R,--R ,;R and NHNO can occupy any positions in the pyridine ring: However, it is preferred thatwhere the -NHNO group: is in the 4-position, the R -substituent should be in thex2-position, except where R -represents an +NO group when it preferably occupies the 3 or 5-position; and-where the '-NHNO group is inmthe 2-position, the'R '-s'ubstituent is in the 4, 5 or 6.p;osition. -1 3:

z: Examples-of nitran'iinopyridinesof-this invention having ltra n nopyridine and itra nkinopyridine; and iii hi-oxides and salts'of the above nitraminopyridine bases. A i i "5- y I The N-oxides of thepresentmvention have the formula "ice mides, the sulphates and the sulphamates, and those with organic acids, for example the oxalates, chloroacetates and benzenes'ulphonates. Also included are the quaternary ammonium salts, for instance the alkyl and aralkyl pyridinium halides and sulphates. The alkyl group attached to the nitrogen atom of the pyridine ring in an alkyl pyridinium salt can for example be one having up to 20 carbon atoms, and the aralkyl group in an aralkyl pyridinium salt can for example be a benzyl or substituted benzyl group.

The nitraminopyridines of the invention may conveniently be made by the action of fuming nitric acid on the corresponding aminopyridine in the presence of sulphuric acid at a temperature below 15 C. The reaction is preferably conducted at least initially at a temperature below 10 C. Where it is desired to substitute an NO group in the ring also, the reaction may comprise a second stage in which the temperature is raised to from -60 to 100 C. The product yield obtained when the temperature of the reaction mixture is held below 10 C. for substantially the whole of a reaction period of from 15 minutes to 6 hours is particularly satisfactory.

A herbicidal composition of the invention can be liquid or solid, and a liquid composition can be a solution, suspension or emulsion. Often a surface active agent is present to stabilize the composition, to facilitate its application, and/ or to improve biological activity.

A composition can contain a nitraminopyridine derivative as the only active ingredient, or one or more other active compounds can be present. Thus the compounds of this invention may be used in combination with other herbicides in order to provide enhanced biological effectiveness. The use of various herbicides in combination at the time of a single application or sequentially is common in practice. Herbicides which may be used in combination with the compounds of this invention include but are not limited to: substituted phenoxyaliphatic acids such as 2,4 dichlorophenoxyacetic acid; 2,4,5 trichlorophenoxyacetic acid, 2 methyl 4 chlorophenoxyacetic acid and the salts, esters and amides thereof; triazine derivatives, such as 2 chloro 4 ethylamino 6-isopropylamino-s-triazine; 2,4 bis-(isopropylamino) 6-methoxys-triazine and '2 methylmercapto 4,6 bis(isopropylamino)-s-triazine; urea derivatives such as 3 (3,4-dichlorophenyl) 1,1 dimethylurea and 3 (m-trifluoromethylphenyl) 1,1 dimethylurea and 3 (3,4-dichlorophenyl) 1 methoxy 1' methylurea; pyridylium derivative such as 1:1 ethylene 2,2 dipyridylium dihalide; lacetanilides such as N-isopropyl-a-chloroacetanilide, and 2' chloro 2',6' diethyl-N-methoxymethyl acetanilide; acetamides such as N,N-diallyl a-chloroacetamide; carbamates such as ethyl-N,N-di-n-propylthiolcarbamate, and 2,3 dichloroallyl diisopropylthiolcarbamate; substituted uracils such as 5 bromo 3-secbutyl-6-methyluracil; substituted anilines such as N,N- diprOpYl-ogogoq-tllflllOlO 2,6 dinitro-p-toluidine; and pyradazone derivatives such as 5-arnino-4-chloro-2- phenyl-B- (,2H) -py'ridazione;

A solution of a nitraminopyridine derivative is one in an organic solvent, for example an alcohol; a ketone; a hydrocarbon, for instance white spirit, solvent naphtha or kerosene; or a halogenated hydrocarbon, for instance perchloroethylene. Where a solution contains a surface active agent, this is selected according to its solubility in the solvent, and non-ionic surface active agents, for example ethers or esters of polyethylene glycols, are generally suitable.

Compositions that are suspensions can be simple ones of the nitraminopyridine derivative in an aqueous medium,

0 stabilized if necessary by the presence of a surface active agent, for instance a non-ionic agent as exemplified above, or an ionic surface active agent, for example a soap or' a synthetic material such as for instance the sodium salt of a long-chain alkylated aromatic sulphonic acid.

A herbicidal emulsion of the invention is usually an aqueous emulsion, and can be obtained by emulsifying a solution of a nitraminopyridine derivative in a suitable organic solvent, generally one that is water-immiscible, with water in the presence of a surface active agent. The surface active agent can be ionic or non-ionic in character.

Compositions which are solids can for instance be those in which the carrier is an inert powder such as for instance kieselguhr or talc. Such a solid composition may also contain a surface active agent to facilitate its application and/or to improve its biological activity.

The proportion of the herbicide employed in the composition will of course vary according to the nature of the composition and the proposed application. Compositions intended for direct application can contain, for example, from 0.001 to 2% by weight of nitraminopyridine and usually contain an amount within the range 0.01 to 1% by weight. Compositions that are concentrates and are intended to be diluted before use may contain for instance from to 95% by weight of nitraminopyridine, for example 25%, 50% or 80% of nitraminopyridine.

The dosage at which a nitraminopyridine derivative of the invention or a herbicidal composition containing such a nitraminopyridine derivative should be applied to obtain the optimum effect, will of course depend on the particular crop concerned and the particular weeds that are to be controlled. Also the activity or selectivity of a herbicide can be modified according to whether it is applied to a pre-emergent or post-emergen stage of plant growth. Normally, however, in foliar treatment for the modification of vegetative growth, the nitraminopyridines are applied in amounts from about 1 to about 50 or more pounds per acre. In applications to soil for the modification of the growth of germinant seeds, germinative seeds, emerging seedlings and established vegetation, the nitraminopyridines are applied in amounts from about 0.1 to about 25 or more pounds per acre. In such soil application, it is desirable that the nitraminopyridines be distributed to a depth of at least 0.2 inches. In selective preemergence phytotoxic applications the nitraminopyridines are usually applied in amounts from about 0.1 to 5 pounds per acre. It is believed that one skilled in the art can readily determine from the teachings of this specification, including examples, the general procedure for any application.

The invention is illustrated by the following examples.

EXAMPLE 1 This example describes the methods used to assess the contact herbicidal activity of compounds in greenhouse tests. The pyridine derivative to be tested was applied in spray form to plants of a given age grown from seed in aluminum pans. After the plants were the desired age, each aluminum pan was sprayed with a given volume of a 0.5% concentration solution of the test chemical, corresponding to a rate of approximately 10 lbs. per acre. This herbicidal solution was prepared from an aliquot of a 1% solution of the test compound in acetone, a known amount of cyclohexanone-emulsifying agent mix, and sufficient water to make up to volume. The emulsifying agent was a mixture comprising 35 wt. percent butylarnine dodecylbenzene sulphonate and 65 wt. percent of a tall oilethylene oxide condensate having about 6 moles of ethylene oxide per mole of tall oil. The injuries to the plants were then observed approximately 14 days later and are reported in the following table. The herbicidal ratings are defined as follows:

0No phytotoxicity 1-Slight phytotoxicity 2-Moderate phytotoxicity 3Severe phytotoxicity 4-Death The nitraminopyridines tested were: 2-bromo-5-chloro-3-nitraminopyridine (A) 2-methyl-S-nitro-6-nitraminopyridine (B) 2-methyl-3-nitro-6-nitraminopyridine (C) Compound Seed type A B 0 Morning glory 3 4 4 Wild oat 1 0 0 1 1 2 EXAMPLE 2 This example describes the production of 2-bromo-5- chloro-3-nitraminopyridine.

1.7 cc. of nitric acid (density 1.5) were added over a period of 20 minutes to a stirred solution of 6 grams (0.029 mole) of 3-amino-2-bromo 5-chloropyridine in 20 cc. of sulphuric acid (density 1.84) at 05 C. The reaction mixture was held at this temperature for a further 2 hours and was then poured into crushed ice, with the addition of dilute ammonium hydroxide solution to a pH of 5, thus precipitating crude 2-bromo-5-cl1loro-3-nitraminopyridine. The solid was filtered and washed with water. After drying, the yield was 5 grams (68%) and the melting point of the product was 111-1 14 C. (dec.). Crystallization from water raised the melting point to 122 C. (dec.).

Found (percent): C, 23.6; H, 1.2; N, 16.3. C H ClBrN O requires (percent): C, 23.6; H, 1.2; N, 16.6.

EXAMPLE 3 This example describes the production of 2-methyl-5- nitro-6-nitraminopyridine.

16.7 cc. of fuming nitric acid (density 1.5 were added over a period of 30 minutes to a stirred solution of 15 grams of 2-methyl-5-nitro-6-aminopyridine in 60 cc. of sulphuric acid (density 1.84) at a temperature of 4-8 C. The reaction mixture was held at this temperature for a further 1% hours and was then poured into 200 grams of crushed ice. The product, crude 2-methyl-5-nit'ro 6- nitraminopyridine, was obtained as a precipitate, which, after the ice had melted, was collected by filtration, washed and dried, to give a yield of 16.7 grams. The meltingpoint, 123-125 C. (dec.) was raised by crystallization from aqueous ethanol to 127 C. (dec.).

Found (percent): C, 36.6; H, 3.07; N, 28.3..C H N O requires (percent): C, 36.4; H, 3.0; N, 28.3.

EXAMPLE 4 2-methy1- 3 nitro 6 nitraminopyridine was obtained from 2-methy1-3-nitro-6-aminopyridine by essentially the same method as that described in Example 3.

The crude product had a melting point of 118-120 C. (dec.) which was raised to 126-127 C. (dec.) by crystallization from water.

Found (percent): C, 35.7; H, 3.0; N, 28.0. C H N O requires (percent): C, 36.4; H, 3.0; N, 28.0.

What is claimed is:

1. A compound of the formula a R NHN02 n a or an N-oxide or salt of said compound, wherein R is I hydrogen or alkyl having from 1 to 6 carbon atoms; R is References Cited chloride, bromine, nitro or alkyl having from 1 to 6 carbon atoms; and R is chlorine, bromine or nitro but differ- 64192 s t 25 1967 cut from R with the further provision that at least one of ep R2 and R3 must be 9 9 5 ALAN L. RO'IMAN, Primary Examiner 2. 2-bromo-5-chloro-3-mtrammopyr1d1ne. 3. Compound according to claim 1 wherein R is chlorhm v US. Cl. X.R.

4. Compound according to claim 1 wherein R is 71--94; 260-294.8 R, 295 S bromine. 1o

Talik et al., Chem. Abstracts, vol. 67, p. 6034, item No.