# US 5,705,691 A · Chemical process

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- Number: US 5,705,691 A
- Document ID: US5705691A
- Status: Granted
- Kind: A
- Application number: 08/676,788
- Filed: 1996-07-08
- Granted: 1998-01-06
- Earliest claimed: 1995-07-10
- Assignees: Zeneca Limited
- Inventors: Stephen M. Brown; James P. Muxworthy; Gareth DeBoos
- Web page: https://patentgrep.com/patent/US5705691A

## CPC

- C07C 303/36: of amides of sulfonic acids
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS

## Abstract

A process for the preparation of an N-(alkylsulphonyl)amide, the process comprising reacting a primary amide with a sulphonyl halide in the presence of a base which is sufficiently strong to cause at least partial deprotonation of the amide.

## Claims

### Claim 1

A process for the production of an N-(alkylsulfonyl)amide, the process comprising reacting a primary amide with a sulfonylhalide in the presence of a base which is sufficiently strong to cause at least partial deprotonation of the amide, the base comprising an alkali or alkaline earth metal, ammonium or quaternary ammonium hydroxide, sodium amide, potassium bistrimethylsilylamide, a reducing metal or an alkali metal carbonate.

### Claim 2 (depends on 1)

A process as claimed in claim 1 wherein the solvent is a co-ordinating solvent such as a cyclic ether, a ketone, a nitrile or a dialkylamide or a two phase system comprising an aqueous phase and an organic phase.

### Claim 3 (depends on 2)

A process as claimed in claim 2, wherein the solvent is tetrahydrofuran or a two phase system comprising an aqueous phase and toluene.

### Claim 4 (depends on 1)

A process as claimed in claim 1, wherein the reaction mixture further comprises an entity having an organic cation.

### Claim 5 (depends on 1)

A process as claimed in claim 1, comprising the initial step of converting an acyl halide to an amide by reaction with ammonia.

### Claim 6 (depends on 1)

A process for the synthesis of 5-(2-chloro-.alpha.,.alpha.,.alpha.-trifluoro-4-tolyloxy)-N-methanesulphon yl-2-nitrobenzamide (fomesafen) from 3-(2-chloro-.alpha.,.alpha.,.alpha.-trifluoro-4-tolyloxy) benzamide, the process comprising, in any order, the steps of nitration and sulphonylation by a process as claimed in claim 1.

### Claim 7 (depends on 6)

A process as claimed in claim 6, the process comprising reacting 3-(2-chloro-.alpha.,.alpha.,.alpha.-trifluoro-4-tolyloxy) benzamide with methane sulphonyl chloride in the presence of a base which is sufficiently strong to be capable of at least partially deprotonating the amide, and nitrating the product.

### Claim 8 (depends on 6)

A process as claimed in claim 6, the process comprising reacting 5-(2-chloro-.alpha.,.alpha.,.alpha.-trifluoro-4-tolyloxy)-2-nitrobenzamide with methane sulphonyl chloride in the presence of a base which is sufficiently strong to be capable of at least partially deprotonating the amide.

### Claim 9 (depends on 4)

A process according to claim 4 wherein the entity having an organic cation comprises tetrabutylammonium hydrogen sulfate.