Process for the preparation of substituted thiazolines and their intermediates

US6894170B2 · kind B2 · utility

Assignee

• DSM Fine Chemicals Austria NFG GmbH & Co KG · AT

Inventors

• Sylvia Krich · Linz, AT
• Alexander Rieder · Kundl, AT
• Ferdinand Heu · Linz, AT
• Gerhard Steinbauer · Ansfelden, AT

Key dates

• Filing date: Oct 15, 2002
• Grant date: May 17, 2005
• Expiry date: Oct 15, 2022

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D277/12
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

Process for the preparation of substituted thiazolines of the formula (I) in which Ar is a phenyl, naphthyl, thienyl, pyridyl or quinolinyl radical which can optionally be substituted by one or more substituents from the group consisting of halogen, OH, benzyloxy, C1-C4-alkyl, C1-C4-alkoxy, COOR1 where R1 is H or C1-C4-alkyl,by coupling of (S)-α-methylcysteine hydrochloride of the formula (II) with a nitrile of the formula (III)Ar—CNin which Ar is as defined above, or a corresponding C1-C4-alkyl imidate, in which (S)-α-methylcysteine hydrochloride of the formula (II) is reacted in a suitable solvent with a nitrile of the formula (III) or a corresponding C1-C4-alkyl imidate in the presence of a tertiary base at a pH of 6.5 to 10 at 50° C. up to the reflux temperature to give the corresponding thiazoline of the formula (I), and processes for the preparation of (S)-α-methylcysteine hydrochloride and its use for the preparation of thiazolines of the formula (I).