SYNTHESIS OF 5,6-DIHYDRO-6-METHYLTHIAZOLO-[2,3-B][1,3]BENZODIAZEPINES, 2,3,10,11-TETRAHYDRO-10-METHYL-1H-CYCLOPENTA[4,5]THIAZOLO[2,3-B][1,3]BENZODIAZEPINE, AND 7,8,9,10,12,13-HEXAHYDRO-13-METHYLBENZOTHIAZOLO[2,3-B][1,3]-BENZODIAZEPINE VIA 1,3,4,5-TETRAHYDRO-5-METHYL-2H-1,3-BENZODIAZEPINE-2-THIONE

Catalytic reductive scission of 4‐methylcinnoline (V) with Raney nickel afforded o‐amino‐β‐methylphenethylamine (IV) in 57% yield. Treatment of IV with carbon disulfide followed by thermal cyclization of the product furnished 1,3,4,5‐tetrahydro‐5‐methyl‐2H‐1,3‐benzodiazepine‐2‐thione (III). Reaction of III with ethyl chloroacetate, ethyl 2‐bromohexanoate, ethyl 2‐chloroacetoacetate, 2‐bromo‐2′‐methoxyacetophenone, and 2‐bromoacetophenone provided a series of substituted 5,6‐dihydro‐6‐methylthiazolo[2,3‐b][1,3]benzodiazepines. Condensation of III with 2‐chlorocyclopentanone and 2‐chlorocyclohexanone gave 2,3,10,11‐tetrahydro‐10‐methyl‐1H‐cyclopenta[4,5]thiazolo[2,3‐b][1,3]benzodiazepine and 7,8,9,10,12,13‐hexahydro‐13‐methylbenzothiazolo[2,3‐b][1,3]benzodiazepine, respectively. Structure assignments are discussed. None of the compounds possessed appreciable biological activity. Copyright © 1969 Journal of Heterocyclic Chemistry