Reactions of 1,4-benzodiazepinic N-nitrosoamidines with tosylmethyl isocyanide:: A novel synthesis of midazolam

Reaction of 1.4-benzodiazepinic N-nitrosoamidines, used as synthetic equivalents of imidoyl chlorides, with the mono-anion of tosylmethyl isocyanide is described. The process gives entry to 3-(4-tosyl)imidazo[1,5-a][1,4]benzodiazepines, compounds which have not been described yet in the literature. These systems can be derivatized to the corresponding trisubstituted 1,4-benzodiazepines by alkylation or acylation of the imidazole ring. These new heterocyclic derivatives are potentially useful in the field of medicinal chemistry. In addition, midazolam 3, the anesthetic properties of which are well established, can be easily prepared in one step by desulfonylation of compound 7a.