A straightforward synthesis of novel 4H‐thiazolo[3,2‐d][1,5]benzodiazepine derivatives

ABSTRACT: The novel 4H-thiazolo[3,2-d][1,5]ben-zodiazepinium salts have been synthesized in a singlestep by the reaction of the variously substituted2,3,4,5-tetrahydro-1,5-benzodiazepine-2(1H)-thionesand bromoacetaldehyde diethyl acetal. Cyclization isobviously influenced by the nature of the substituentsin the benzodiazepine system. Theoretical modelingand B3LYP DFT computational studies are pre-sented. 2004 Wiley Periodicals, Inc. Heteroatom Chem C15:363–368, 2004; Published online in Wiley InterScience(www.interscience.wiley.com). DOI 10.1002/hc.20026 INTRODUCTION Benzodiazepines and their annelated derivatives ex-hibit a wide spectrum of biological activities andhave found applications in pharmaceutical chem-istry [1]. More recently, considerable efforts havebeen devoted to discover new biologically activecompounds in antitumor antibiotic group by the re-placement of the pyrrole fused ring of pyrrolo[2,1- c ][1,4]benzodiazepine system by thiazole moiety [2].Moreover, a series of thiazolo[3,4-

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