Process for the preparation of herbicidal sulfonylureas and of N-(pyrimidinyl or triazinyl)-carbamates as intermediate products

US5936085A · kind A · utility

Assignee

• Hoechst Schering Agrevo GmbH · DE

Inventors

• Gerhard Schnabel · Elsenfeld, DE
• Harald Knorr · Frankfurt am Main, DE
• Klemens Minn · Hattersheim, DE
• Jan Vermehren · Cambridge, GB

Key dates

• Filing date: Jul 11, 1996
• Grant date: Aug 10, 1999
• Expiry date: Jul 11, 2016

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D251/16
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

Disclosed and claimed is a process for the preparation of a carbamate (IV) EQU Ar--O--CO--NR--B (IV) by reaction of a salt EQU M.sup..sym. .crclbar.NR--B (II-S) with a diaryl carbonate EQU (ArO).sub.2 CO (III). The carbamate can be reacted, without any necessity of intermediate isolation, with a sulfonamide A--SO.sub.2 NH.sub.2 (V) to give a sulfonylurea (I) or salts thereof EQU A--SO.sub.2 --NH--CO--NR--B (I). And thus, disclosed and claimed too is a process for the preparation of sulfonylurea (I) by (i) contacting a salt (II-S) with a diaryl carbonate (III) to form a carbamate (IV), and (ii) contacting carbamate (IV) from step (i) with or without intermediate isolation, with a sulfonamide (V). These processes avoid the use of alkali metal hydrides as a base. And, these processes can additionally include the preparation of salt (II-S) from a compound H--NR--B (II) and base M.sup..sym. Base.sup..crclbar..