3‐α‐Bromacetyl‐cumarine als Synthesebausteine für Heterocyclisch substituierte Cumarine

Abstract

3‐α‐Bromacetyl‐coumarines as Synthones for Heterocyclic Substituted Coumarines3‐α‐Bromacetyl‐coumarines 2 react easily and in high yields with thiourea and thioamide derivatives 3 and 5, resp., to 4‐coumar‐3′‐yl‐thiazoles 4 and 6, resp., as well as with N,N‐disubstituted thioamides 11 and N,N,N′,N′‐tetraalkylthiourea 12 to 5‐coumar‐3′‐yl‐oxathioliumsalts 13 and 14, respectively. In a two‐step reaction 2 can be transformed by reaction with aniline 17 to 4‐coumar‐3′‐yl‐imidazoles 21 and 5‐coumar‐3′‐yl‐oxazoliumsalts 22, resp., via aminoketone intermediates 18.