An Efficient Synthesis of Thio- and Thiazoloquinazolinones by the Electrochemical Oxidation of Catechols in the Presence of 2-Mercapto-4(3H)-quinazolinone

摘要

Thio- and thiazoloquinazolinones were synthesized efficiently by the anodic oxidation of catechols in the presence of 2-mercapto-4(3H)-quinazolmone in aqueous solution. 4-Methylcate-chol and 3-methoxycatechol convert into thioquinazolinones via an EC (E: electron transfer, C: chemical reaction) pathway. Catechol, 3-methylcatechol, and 3,4-dihydroxybenzoic acid convert into thiazoloquinazolinones via an ECEC pathway.Quinazolinone A and its derivatives (Figure 1) are known to have a broad range of pharmaceutical properties, such as anticancer, anti-inflammatory, anticonvulsant, and an-tidiuretic activities.1"7 The presence of the thiazole ring in many natural and synthetic quinazolinones has generated interesting biological properties.8-9 Moreover, thiazo-lo[2,3-6]quinazolinones B (Figure 1) are potentially interesting from a biological and synthetic point of view. A number of classic methods for the preparation of thiazoloquinazolinones have been developed.