2-Aminothiophenes and 2-amino-4,5-dihydrothiophenes were selectively and conveniently synthesized from 4-thiazolidinone derivatives. The meaningful product 10m was efficiently synthesized, which is a commonly-used intermediate for preparing Olanzapine. The present method holds many advantages, such as easy operation, high yields, catalyst-free and using of water as the solvent.

Thiazolidinones are selectively converted into thiophene or dihydrothiophenes upon treatment with NaBH4 and KBH4, respectively.