GB1589681A

GB1589681A - Isomeric mixture of trimethylperhydroazepine-1-thiocarboxylic acid s-ethyl esters process for the manufacture of this mixture and also its use as a herbicide

Info

Publication number: GB1589681A
Application number: GB28993/77A
Authority: GB
Original assignee: Schering AG
Current assignee: Bayer Pharma AG
Priority date: 1976-07-16
Filing date: 1977-07-11
Publication date: 1981-05-20
Also published as: DE2632676A1; NL7706148A; NO146094C; TR19702A; LU77760A1; FR2358397A1; DK323777A; AT360265B; PL199634A1; AU512006B2; DD130549A5; BG32413A3; PT66813B; ATA508677A; ES460670A1; IT1077338B; CA1096379A; BE856861A; RO71240A; PL103046B1

Abstract

A herbicide comprises S-ethyl 3,3,5- and/or 3,5,5-trimethylperhydroazepine-1-thiocarboxylate(s) of the formula(e) <IMAGE> and/or <IMAGE> as at least one active substance. A process for the production of the herbicide is described.

Description

(54) ISOMERIC MIXTURE OF TRIMETHYLPERHYDROAZEPINE-I THIOCARBOXYLIC ACID S-ETHYL ESTERS, PROCESS FOR THE MANUFACTURE OF THIS MIXTURE AND ALSO ITS USE AS A HERBICIDE (71) We, SCHERING AKTIENGELLSCHAFT, a Body Corporate organised according to the laws of Germany, of Berlin and Bergkamen, Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention is concerned with a new 1: 1-isomeric mixture of trimethylperhydroazepine-1-thiocarboxylic acid S-ethyl esters, a process for the manufacture of such a mixture and also its use as a herbicide.

The problem upon which the present invention is based has been to provide a herbicidally active agent having a wide spectrum of selectivity towards crop plants and a very good herbicidal action against weeds.

This problem is solved in accordance with the present invention by the isomeric mixture defined in the following paragraph.

The present invention accordingly provides a 1:1-isomeric mixture of 3,3,5trimethylperhydro-azepine-l-thiocarboxylic acid S-ethyl ester of the formula Ia

and 3,5,5-trimethyl-perhydro-azepine-l-thiocarboxylic acid S-ethyl ester of the formula Ib

German Offenlegungsschrift No. 2,333,397 describes and claims compounds of the general formula

where X denotes oxygen or sulphur, R' denotes ethyl or 2 or 3 radicals which are independently selected from ethyl and methyl, and R2 denotes a hydrocarbon radical which is unsubstituted or substituted by one or more substituents independently selected from halogen, hydroxyl, cyano, alkoxy and nitro, nitro if present being attached to a benzene ring, and their use as herbicides.

The isomeric mixture of ethyl esters of the present invention has the special advantage that it has an outstanding herbicidal action, for example against the weeds Tritium, Hordeum and Setaria. This outstanding herbicidal action against Triticum, Hordeum and Setaria is completely unexpected, because the corresponding isomeric mixture of methyl esters and the corresponding isomeric mixture of n-propyl esters both of which are disclosed in German Offenglegungsschrift No. 2,333,397 (and which are of course structurally analogous) do not have a satisfactory herbicidal action against all these weeds. As can be seen from the test results given in Example 3 below the corresponding isomeric mixture of n-propyl esters is ineffective against Triticum and Hordeum and both the corresponding isomeric mixture of n-propyl esters and the corresponding isomeric mixture of methyl esters have a minimal effectiveness against Setaria.

The isomeric mixture of the present invention is also distinguished by an outstanding herbicidal action against other monocotyledonous weeds, for example Avena, Alopecurus, Echinochloa, Digitaria, Sorghum and Poa.

Owing to its excellent selective properties, the isomeric mixture of the present invention can be used in agricultural crops, for example cauliflower, sugar beet, seeded tomato, cotton and soya crops.

The isomeric mixture of the present invention can also be used in maize and sorghum, it being of advantage to mix antidotes, for example 8-naphthalic anhydride or N,Ndiallyldichloracetamide, with the seed grain or spraying preparation respectively.

A further advantage of the isomeric mixture of the present invention is that it also has growth-regulating properties.

The isomeric mixture acts satisfactorily even at rates of application of from lkg of active substance per hectare, and, owing to its surprisingly wide spectrum of selectively, can be used in quantities of up to 8 kg of active substance per hectare before sowing by incorporation in the soil.

The present invention accordingly also provides a herbicidal preparation which comprises the isomeric mixture of the present invention in admixture or conjunction with a suitable carrier.

The present invention further provides a method of protecting a living plant against weeds, wherein the area in the vicinity of the living plant is treated with the isomeric mixture of the present invention.

The present invention further provides a method of protecting a crop area against weeds, wherein the crop area is treated with the isomeric mixture of the present invention.

The present invention further provides a pack which comprises the isomeric mixture of the present invention together with instructions for its use as a herbicide.

The isomeric mixture of the present invention can be used either alone or in admixture with other active substances.

Depending on the purpose desired, there are mentioned in this connection by way of example the following herbicidally active substances, which, if desired, may be added immediately before the use of the isomeric mixture of the present invention: substituted anilines, substituted aryloxycarboxylic acids and also salts, esters and amides thereof. substituted ethers, substituted arsonic acids and also salts, esters and amides thereof, substituted benzimidazoles, substituted benzisothiazoles, substituted benzthiadiazinone dioxides, substituted benzoxazines, substituted benzoxazinones, substituted benzthiazoles, substituted benzthiadiazines, substituted biurets, substituted quinolines, substituted carbamates, substituted aliphatic carboxylic acids and also salts, esters and amides thereof, substituted aromatic carboxylic acids and also salts, esters and amides thereof, substituted carbamoylalkyl-thio- or dithio-ph,osphates, substituted quinazolines, substituted cycloalkylamidocarbothiolic acids and also salts, esters and amides thereof, substituted cycloalkylcarbonamido-thiazoles, substituted dicarboxylic acids and also salts, esters and amides thereof, substituted dihydrobenzofuranylsulphonates, substituted disulphides, substituted dipyridylium salts, substituted dithiocarbamates, substituted dithiophosphoric acids and also salts, esters and amides thereof, substituted ureas, substituted hexahydro-lH-carbothioates, substituted hydantoins, substituted hydrazides, substituted hydrazonium salts, substituted isoxazolepyrimidones, substituted imidazoles, substituted isothiazolepyrimidones, substituted ketones, substituted naphthoquinones, substituted aliphatic nitriles, substituted aromatic nitriles, substituted oxadiazoles, substituted oxadiazinones, substituted oxadiazolidinediones, substituted oxadiazinediones, substituted phenols and also salts and esters, thereof, substituted phosphonic acids and also salts, esters and amides thereof, substituted phosphonium chlorides, substituted phosphonalkylglycines, substituted phosphites, substituted phosphoric acids and salts, esters and amides thereof, substituted piperidines, substituted pyrazoles, substituted pyrazolalkylcarboxylic acids and also salts, esters and amides thereof, substituted pyrazolium salts, substituted pyrazolium alkyl sulphates, substituted pyridazines, substituted pyridazones, substituted pyridine carboxylic acids and also salts, esters and amides thereof, substituted pyridines, substituted pyridine carboxylates, substituted pyridinones, substituted pyrimidones, substituted pyrrolidine carboxylic acids and also salts, esters and amides thereof, substituted pyrrolidines, substituted aryl sulphonic acids and also salts, esters and amides thereof, substituted styrenes, substituted tetrahydro-oxadiazinediones, substituted tetrahydromethanoindenes, substituted tetrahydro-diazole-thiones, substituted tetrahydro-thiadiazine-thiones, substituted tetrahydro-thiadiazolediones, substituted thiadiazoles, substituted aromatic thiocarboxylic acid amides, substituted thiocarboxylic acids and also salts, esters and amides thereof, substituted thiolcarbamates, substituted thiophosphoric acids and also salts, esters and amides thereof, substituted triazines, substituted triazoles, substituted uracils and substituted uretidinediones.

There may also be used other additives, for example non-phytotoxic additives, which produce with herbicides a synergistic increase in action, for example wetting agents, emulsifiers, solvents and oily additives.

The isomeric mixture of ethyl esters of the present invention is advantageously used in the form of herbicidal preparations, for example powders, strewable preparations, granules, solutions, emulsions or suspensions, with the addition of liquid and/or solid vehicles or diluents and, if desired, of surface-active agents, for example wetting, adherent, emulsifying and/or dispersing agents.

Suitable liquid carriers are, for example, water, aliphatic hydrocarbons, aromatic hydrocarbons, for example benzene, toluene and xylene, cyclohexanone, isophorone, dimethyl sulphoxide and dimethylformamide, and also mineral oil fractions.

As solid carriers there are suitable, for example, mineral earths, for example tonsil, silica gel, talcum, kaolin, attaclay, limestone and silicic acid, and vegetable products, for example meals.

As surface-active agents there may be mentioned, for example, calcium lignin sulphonate, polyoxyethylalkyl-phenyl ethers, naphthalene sulphonic acids and salts thereof, phenol sulphonic acids and salts thereof, formaldehyde condensates, fatty alcohol sulphates and also substituted benzene sulphonic acids and salts thereof.

The proportion of active substance in the various herbicidal preparations may vary within wide limits. For example, the preparations may contain 10 to 80% by weight of active compound(s), 90 to 20% by weight of liquid or solid carrier and, if desired, also up to 20% by weight of surface-active agent(s).

The active isomeric mixture of the present invention may be applied in the usual manner, for example with water as carrier in quantities of spray liquor of 100 to 1000 litres per hectare. It is also possible to apply the active mixture by the so-called "low volume" and "ultra-low volume" methods, and also in the form of so-called microgranules.

The present invention further provides a process for the manufacture of the isomeric mixture of the ester of the formula Ia and the ester of the formula Ib, wherein an isomeric mixture (if desired dissolved in a solvent) of trimethyl-perhydroazepines of the formulae

(a) is reacted, if desired in the presence of an acid-binding agent, with chloro-thioformic acid S-ethyl ester of the formula Cl-CO-S-C2H5, or (b) is reacted in the presence of a base with carbon oxysulphide of the formula O=C=S to form salts of such a base of the general formulae

in which B represents a cation derived from the base, and the salts are treated with an ethylating agent of the general formula H5C2-Z, in which Z represents a halogen atom, an ethyl sulphuric acid group or a toluene sulphonic acid group, or (c) is reacted with phosgene of the formula

to form trimethylperhydroazepine-l-carboxylic acid chlorides of the formulae

which are then reacted with ethyl mercaptan of the formula HsC2-SH or with a salt of such a mercaptan, if desired in the presence of an acid-binding agent.

The product of the process may be isolated in a known manner.

As bases or acid-binding agents there may be used all the usual proton acceptors. For this purpose there are suitable organic bases, for example tertiary amines, for example triethylamine or N,N-dimethylaniline, or pyridine bases, and suitable inorganic bases, for example oxides, hydroxides and carbonates of alkali and alkaline earth metals. Liquid bases may serve simultaneously as solvents. This applies also to the liquid starting bases, if they are used in excess as acid capturer.

The reaction of the components may be carried out at between 0 and 1200C, but generally at room temperature.

For the synthesis of the isomeric mixture of the present invention the reactants are preferably used in equimolar quantities.

Suitable reaction media are solvents inert towards the reactants, either alone or in admixture with water.

Amongst many such reaction media the following may be mentioned by way of example, namely aliphatic and aromatic hydrocarbons, for example petroleum ether, cyclohexane, benzene, toluene and xylene, halogenated hydrocarbons, for example methylene chloride, chloroform, carbon tetrachloride and halogenated ethylenes, ether-like compounds, for example diethyl ether, diisopropyl ether, tetrahydrofuran and dioxan, ketones, for example acetone, methyl isobutyl ketone and isophorone, esters, for example methyl and ethyl acetates, acid amides, for example dimethylformamide and hexamethyl-phosphoric acid triamide, and carboxylic acid nitriles, for example acetonitrile.

Finally, the isolation of the isomeric mixture of the present invention may be carried out in a manner known per se by distilling off the solvents used under atmospheric or reduced pressure, optionally after treatment with acid or basic agents to remove undesired by-products.

The starting compounds for preparing the isomeric mixture of the present invention are known or can be prepared by methods known per se. The isomeric mixture of the present invention containing the two isomers 3,3 ,5-trimethyl-perhydro-azepine-l-thiocarboxylic acid S-ethyl ester and 3,5,5-trimethyl-perhydro-azepine-l-thiocarboxylic acid S-ethyl ester in the ratio by weight of 1:1 is a pale yellow coloured oil having a feebly aromatic odour, which is insoluble in water, but readily dissolves in all organic solvents, for example hydrocarbons, halogenated hydrocarbons, ethers, ketones, carboxylic acid esters, carboxylic acid amides, carboxylic acid nitriles, alcohols, carboxylic acids, sulphoxides and many others.

The following Examples illustrate the invention. Example 1 illustrates the process of the present invention and Examples 2 and 3 illustrate the possibilities of use of the isomeric mixture of the present invention.

Example 1 66.4 ml of a 1:1-isomeric mixture of 3,3,5-trimethyl- and 3,5,5-trimethyl-perhydroazepine were dissolved in 150 ml of diisopropyl ether, and 25 gms of chloro-thioformic acid S-ethyl ester were added dropwise at room temperature while stirring. The reaction mixture was stirred for a further hour, then extracted by agitation with water, then with dilute hydrochloric acid and again with water, the ether phase was dried over magnesium sulphate, the solvent was distilled off in vacuo and finally the remainder of the solvent was removed under a high vacuum.

45 gms (98% of the theoretical yield) of 3,3,5(3,5,5)-trimethyl-perhydro-azepine-l- thiocarboxylic acid S-ethyl ester having an n' value of 1.5041 were obtained. By the addition of a sodium hydroxide solution to the first aqueous extract 28.3 gms of the starting base used in excess were recovered.

Analysis: Calculated C 62.83% H 10.11% N 6.11% Found C 62.66% H 10.28% N 5.97% Example 2 In a series of tests carried out in a greenhouse the plants listed in the Table below were treated before their emergence with the agents mentioned at the rate of application of 3 kg of active substance per hectare. For this purpose the agents were in each case applied uniformly to the soil in the form of an aqueous dispersion at the rate of 500 litres per hectare, and then worked into the soil. Three weeks after the treatment the results showed that the isomeric mixture of the present invention was better than the agent used for comparison. The results are expressed by a numerical scale extending from 0 to 10, the value 0 representing total destruction and the value 10 representing no damage.

Active substance of the present invention kg/ha of active substance Cotton Soya bean Rice Triticum Hordeum Avena Alopecurus Echinochloa Setaria Digitaria Sorghum Poa 3,3,5(3,5,5)-Trimethyl-perhydroazepine-1-thiocarboxylic acid Sethyl ester 3 10 10 0 0 0 0 0 0 0 0 0 0 Agent for comparison (according to United States Patent Specification No. 3,198,786) S-Ethyl-N,N-hexamethylene thiocarbamate 3 0 3 10 10 10 0 0 0 3 3 3 8 Untreated control 10 10 10 10 10 10 10 10 10 10 10 10 0 = total destruction 10 = not damaged Example 3 Description of the tests The purpose of the comparative tests carried out in this Example was to determine the herbicidal action of the isomeric mixture of the present invention as compared with the structurally analogous corresponding isomeric mixture of methyl esters and corresponding isomeric mixture of n-propyl esters disclosed in German Offenlegungsschrift No. 2,333,397.

In the comparative tests the cultivated plants and weeds listed in the Table of results below were treated under hot-house conditions prior to their emergence with the listed agents at a rate of application of approximately 3 kg of active substance per hectare. For this purpose the agents were in each case applied uniformly over the surface of the soil in the form of an aqueous dispersion using 500 liters per hectare, and then finally worked into the soil.

Three weeks after the treatment an evaluation of the effectiveness of the agents was carried out by a visual control according to the following numerical scale: 0 = 100% destruction 6 = 40% destruction 1 = 90% destruction 7 = 30% destruction 2 = 80% destruction 8 = 20% destruction 3 = 70% destruction 9 = 10% destruction 4 = 60% destruction 10 = no damage 5 = 50% destruction Test results Cotton Soya bean Rice Triticum Hordeum Echinochloa Setaria Digitaria Sorghum Compounds of the invention: Isomeric mixture of 3,3,5(3,5,5)-trimethylperhydro-azepine-1-thiocarboxylic acid S-ethyl ester 10 10 0 0 0 0 0 0 0 Comparison Compounds: Isomeric mixture of 3,3,5(3,5,5)-trimethyl-perhydroazepine-1-thiocarboxylic acid S-methyl ester (German Offenlegungsschrift No. 2,333,397) 10 7 2 3 0 2 8 2 1 Isomeric mixture of 3,3,5(3,5,5)-trimethyl-perhydroazepine-1-thiocarboxylic acid S-n-propyl ester (German Offenlegungsschrift No. 2,333,397) 10 10 1 10 10 2 6 3 2 Untreated Control 10 10 10 10 10 10 10 10 10 Evaluation The test results clearly show the outstanding herbicidal action of the isomeric mixture of the present invention coupled with its selectivity with respect to the cultivated plants cotton and soya bean. This herbicidal action can be seen to be superior to the structurally analogous isomeric mixtures used for comparison. The isomeric mixtures used for comparison showed both an insufficient action against the weeds and an inadequate selectivity with respect to the cultivated plants.

Claims

WHAT WE CLAIM IS:

1. A 1:1-isomeric mixture of 3,3,5-trimethyl-perhydro-azepine-l-thiocarboxylic acid S-ethyl ester of the formula Ia

2. A process for the manufacture of an isomeric mixture as claimed in claim 1, wherein a 1:1-isomeric mixture of trimethylperhydroazepines of the formulae

(a) is reacted with chloro-thioformic acid S-ethyl ester of the formula Cl-CO-S-C2H5, or (b) is reacted in the presence of a base with carbon oxysulphide of the formula O=C=S to form salts of such a base of the general formulae

in which B represents a cation derived from the base, and the salts are treated with an ethylating agent of the general formula HsC2-Z, in which Z represents a halogen atom, an ethyl sulphuric acid group or a toluene sulphonic acid group, or (c) is reacted with phosgene of the formula

to form trimethylperhydroazepine-l-carboxylic acid chlorides of the formulae

which are then reacted with ethyl mercaptan of the formula HsC2-SH or with a salt of such a mercaptan.

3. A process as claimed in claim 2 wherein each of the reactions with the chloro-thioformic acid S-ethyl ester and with the ethyl mercaptan or salt thereof is carried out in the presence of an acid-binding agent.

4. A process as claimed in claim 2, conducted substantially as described herein.

5. A process as claimed in claim 2, conducted substantially as described in Example 1 herein.

6. A herbicidal preparation which comprises an isomeric mixture as claimed in claim 1, in admixture or conjunction with a suitable carrier.

7. A preparation as claimed in claim 6, which is in the form of a powder, a strewable preparation, granules, a solution, an emulsion or a suspension.

8. A preparation as claimed in claim 6 or 7, wherein the isomeric mixture is present in an amount of 10 to 80% by weight.

9. A preparation as claimed in any one of claims 6 to 8, containing a single surface-active agent in an amount of up to 20% by weight.

10. A preparation as claimed in any one of claims 6 to 8, containing two or more surface-active agents in a total amount of up to 20% by weight.

11. A herbicidal preparation as claimed in claim 6 and substantially as described in Example 2 herein.

12. A method of protecting a living plant against weeds, wherein the area in the vicinity of the living plant is treated with an isomeric mixture as claimed in claim 1.

13. A method as claimed in claim 12, wherein the area is treated with a herbicidal preparation as claimed in any one of claims 6 to 11.

14. A method as claimed in claims 12 or 13, wherein the isomeric mixture is used for the treatment in an amount within the range of from 1 to 8 kg per hectare.

15. A method as claimed in claim 12, conducted substantially as described in Example 2 herein.

16. A method of protecting a crop area against weeds, wherein the crop area is treated with an isomeric mixture as claimed in claim 1.

17. A method as claimed in claim 16, wherein the crop area is treated with a herbicidal preparation as claimed in any one of claims 6 to 11.

18. A method as claimed in claim 16 or 17, wherein the isomeric mixture is used for the treatment in an amount within the range of from 1 to 8 kg per hectare.

19. A method as claimed in any one of claims 16 to 18, wherein the crop is a cauliflower, sugar beet, seeded tomato, cotton, soya, maize or sorghum crop.

20. A pack which comprises an isomeric mixture as claimed in claim 1, together with instructions for its use as a herbicide.