Über die Reaktion von α‐Aminobenzylcyanid mit Aldehyden und Schwefel

Abstract

Bei der gemeinsamen Einwirkung von aromatischen Aldehyden und Schwefel auf α‐Aminobenzylcyanid entstehen 5‐Arylidenamino‐2‐aryl‐4‐phenylthiazole 1, aus denen durch hydrolytische Spaltung die freien 5‐Amino‐2‐aryl‐4‐phenyl‐thiazole 2 erhalten werden.

Convenient Synthesis of NovelN-Substituted-5-aminothiazole Derivatives

“…Less is known about efficient syntheses of 2,4-diarylthiazoles functionalized at the 5 position. Literature syntheses of 2,4-diaryl-5-aminothiazoles ( 1) (Scheme ) include: (i) the photoconversion of unstable azirene 2 into 1 (where Ar = R 1 = Ph, R 2 = H) in a 20% yield; (ii) the condensation of unstable ω-chloro-ω-acylamidoacetophenones ( 3 ) with benzothioamide to generate 1 (where Ar = Ph, R 1 = COR 3 , R 2 = H) in 64−94% yields, which is limited by the need to access of 3 , via condensation of phenylglyoxal with acid amides and thionyl chloride; (iii) a general method of synthesizing 5-(arylidenamino)-2-aryl-4-phenylthiazoles in 25−75% yields, as presented by Gewald et al In these syntheses, phenyl was the only 4-substituent and yields were low for the thiazoles bearing electron-withdrawing groups in the 2 position (25%).

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