Condensation of 2-(4-chlorophenyl)ethanol (I) with 4-nitrobenzaldehyde (II) by means of ZnCl2 and HCl produced isochromane (III). Subsequent oxidative cleavage of (III) employing Jones reagent in acetone afforded ketoacid (IV). Conversion of (IV) to the corresponding hydrazone (V), followed by cyclization in the presence of dicyclohexylcarbodiimide yielded benzodiazepinone (VI). After conversion of (VI) to the benzodiazepine thione (VII) by treatment with P2S5, condensation with 2-(1-aminoethyl)-1,3-dioxolane (VIII) employing HgO as the desulfurizing reagent furnished (IX). Further acid-catalyzed cyclization of (IX) gave rise to the imidazobenzodiazepine (X). Finally, the nitro group of (X) was reduced by transfer hydrogenation using hydrazine and Raney Nickel.

Condensation of 2-(4-chlorophenyl)ethanol (I) with 4-nitrobenzaldehyde (II) by means of ZnCl2 and HCl produced isochromane (III). Subsequent oxidative cleavage of (III) employing Jones reagent in acetone afforded ketoacid (IV). Conversion of (IV) to the corresponding hydrazone (V), followed by cyclization in the presence of dicyclohexylcarbodiimide yielded benzodiazepinone (VI). After conversion of (VI) to the benzodiazepine thione (VII) by treatment with P2S5, condensation with 2-(1-aminoethyl)-1,3-dioxolane (VIII) employing HgO as the desulfurizing reagent furnished (IX). Further acid-catalyzed cyclization of (IX) gave rise to the imidazobenzodiazepine (X). Finally, the nitro group of (X) was reduced by transfer hydrogenation using hydrazine and Raney Nickel.