Vapor phase phototransposition of pyrazine deuterium labeling studies

摘要

2,5-Dideuteriopyrazine (l-2,5-d2) and 2,6-dideuteriopyrazine (l-2,6-d2) phototranspose in the vapor phase to mixtures of 4,6-dideuteriopyrimidine (2-4,6-d2) and 2,5-dideuteriopyrimidine (2-2,5-d2) or 4,5-dideuteropyrimidine (2-4,5-d2) and 2,4-dideuterio-pyrimidine (2-2,4-d2),respectively.In each case,a trace quantity of a dideuteriopyridazine (7-d2) photoproduct was also observed.These products are consistent with a diazaprefulvene mechanism involving,2,6-bonding,one or two nitrogen migrations,and rearomatization.