Synthesis of thiazole-containing benzo-crown ethers

A series of benzo-crown ethers containing the thiazole subcyclic moity have been synthesized. Reaction of 1,2-bis(thioamidomethyloxy)benzene 2 with ethyl bromopyruvate in ethanol provided 1,2-bis(thiazolyl)benzene 4 (80%) along with thiazole 5 (14%). Reduction of 4 with lithium aluminum hydride followed by mesylation-bromination gave 7. Similar treatment of 5 with Lithium aluminum hydride followed by bromination resulted in 12. Benzocrown ethers 8, 9, 10, and 13 were prepared from the reactions of 4-bromomethylthiazole derivatives 7 and 12 with catechol and resorcinol derivatives in the presence of potassium hydride.