Reduction of 6,6,9,9-Tetramethylhexahydroimidazo[2,1-d][1,2,5]dithiazepine With Borane

Abstract

Treatment of 6,6,9,9-tetramethylhexahydroimidazo[2,1-d][1,2,5]dithiazepine (3) with borane- tetrahydrofuran complex (BH₃.thf) gave trihydro(6,6,9,9-tetramethylhexahydroimidazo[2,1-d] [1,2,5]dithiazepine-_KN¹)boron (5) which was reduced to 3,3,10,10-tetramethyl-1,2-dithia-5,8- diazacyclodecane (2) upon treatment with hydrochloric acid. Reduction of 3,3,10,10-tetramethyl-1,2-dithia-5,8-diazacyclodeca-4,8-diene (1) gave a mixture of (5) and trihydro(3,3,10,10-tetramethyl-1,2-dithia-5,8-diazacyclodecane-_KN⁵)boron (6) as intermediates which were converted into (2) with hydrochloric acid. The structures of (2), (5) and (6) were determined by X-ray crystallography.