Generation of the iminyls 1d and 1e by standard methods in the gas-phase by
flash vacuum pyrolysis (FVP), or in solution, respectively, gives rise to
1,3-benzoxazines 18 and 22 by a mechanism which probably involves a 1,6-hyd
rogen atom translocation. Under FVP conditions, 2-cyanophenol 14 is a major
product from 2-alkoxyphenyl-alkaniminyls 1b-d; the dealkylation is an inte
gral part of the reaction mechanism and not a subsequent reaction of 2-alko
xybenzonitriles, which themselves are only very minor products of the pyrol
yses.