Synthesis of 2‐Aminothiazole Derivatives in Easy Two‐Step,One‐Pot Reaction

Condensation of brominated ethyl acetoacetate with thiourea gives 2‐amino‐5‐ethoxycarbonyl‐4‐methylthiazole ( 1 ) and ethyl α‐(2‐amino‐4‐thiazolyl)acetate ( 2 ), indicating that bromination of the substrate occurs on both sides of the carbonyl group. X‐ray diffraction studies indicate weak hydrogen bonds of the amino groups, which are not observed in the IR spectra. The 1 molecule adopts planar S,O‐anti conformation in the crystal lattice, whereas the methylene group, insulating thiazole ring and the ester group in 2 molecule, makes it more flexible and makes the ester group nearly perpendicular to the thiazole ring. The small deviations of the bond lengths and angles indicate mesomeric interaction between complementary substituents across the thiazole ring.