Abstract

Since the amino and the hydroxyl groups of 4-(2-hydroxyphenyl)-2-phenyl-2, 3-dihydro-1H-1, 5- benzodiazepine can both act as nucleophiles, the introduction of both an N-acetyl and an O-acetyl group is expected when the compound is allowed to react with an excess of an electrophile such as acetic anhydride. An intramolecular hydrogen bond between OH and N-5 of the benzodiazepine has been used to obtain differentiation between the two possible sites of acetylation. Thus, this feature offers a preparatively utilizable protecting effect for the OH group and allows for a regioselective N-acetylation at ambient temperature. Both mono- and diacetylated compounds were prepared and characterized by crystal structure analysis. ©2009 Verlag der Zeitschrift für Naturforschung Tübingen.