Efficient synthesis of thioquinazolinedione derivatives via the reaction of 2-aminobenzonitrile and carbonyl sulfide catalyzed by NaHS.

An efficient method for the synthesis of thioquinazolinediones from 2-aminobenzonitriles and carbonyl sulfide (COS) catalyzed by NaHS was established. In this synthetic method, NaHS was used to catalyze the reaction of COS with a broad range of 2-aminobenzonitrile to form the corresponding thioquinazolinedione. Moreover, the controlled experiments demonstrated that NaHS not only reacted with 2-aminobenzonitrile to form 2-aminobenzothioamide, but also acted as a strong nucleophile to react with COS to form the active intermediate dithiocarbonate. Subsequently, 2-aminobenzothioamide reacted with dithiocarbonate to form the thioquinazolinedione easily. Meanwhile, the generated H2S was recycled as sulfur source and hydrogen source to produce 2-aminobenzothioamide. [ABSTRACT FROM AUTHOR]