Syntheses and reactions of 2‐halo‐5‐thiazolecarboxylates

A variety of 2‐halo‐5‐thiazolecarboxylates was prepared from substituted‐3‐aminoacrylates and 3‐ketoes‐ters. Selective reduction of 2‐chloro‐5‐thiazolecarboxylates 4a, 4i and 4j with sodium borohydride in ethanol provided the corresponding 2‐halo‐5‐thiazolemethanols 27‐29. Nucleophilic displacements on [2‐chloro‐4‐(trifluoromethyl)‐5‐thiazolyl]methyl methanesulfonate (32c) occurred selectively at the 5‐substituent to provide 2‐chloro‐4‐(trifluoromethyl)‐5‐(heteroatom‐substituted‐methyl)thiazoles 32d‐f.