Synthesis of some 2,5-benzoxazocine and 2,6-benzoxazonine derivatives from ω-(Dihydroisoindol-2-yl)alkanol precursors by means of cyanogen bromide

Abstract

Reaction of cyanogen bromide with 2-(1-phenyl-2,3-dihydro-1H-isoindol-2-yl)ethanol (5a) gave 1-phenyl-3,4,5,6-tetrahydro-1H-2,5-benzoxazocine-5-carbonitrile (6a) in a low to moderate yield. Similarly, 3-(1-phenyl-2,3-dihydro-1H-isoindol-2-yl)propan-1-ol (5c) gave 1-phenyl-1,3,4,5,6,7-hexa-hydro-2,6-benzoxazonine-6-carbonitrile (6c). The analogous 1-(4-methoxyphenyl) derivatives of both medium ring systems were also prepared, and some mechanistic aspects of the results are discussed. Conversion of (6a) into the analgesic, Nefopam,is described.