Transformations of 6-[4-(methylthio)phenyl]-3-(2-pyridyl)-1,2,4-triazines in the reaction with an aryne intermediate

Transformations of the various 6-[4-(methylthio)phenyl]-3-(2-pyridyl)-1,2,4-triazines in their reactions with an aryne intermediate were investigated. It was shown that the interaction of a 5-unsubstituted triazine with the aryne led to an S-arylation product, whereas there were no any transformations of the pyridyltriazine system. Introduction of the pentafluorophenyl substituent at the C(6) position of the triazine changed the pathway in this reaction with the aryne, which proceeded simultaneously at two reaction centers. In particular, there were a rearrangement of the 3-(2-pyridyl)-1,2,4-triazine into the 10-(1H-1,2,3-triazol-1-yl)pyrido[1,2-a]indole system as well as S-arylation. The product of dual functionalization, 10-{5-perfluorophenyl-4-[4-(phenylthio)phenyl]-1H-1,2,3-triazol-1-yl}pyrido[1,2-a]indole, exhibited a blue emission at λem = 395 nm and a fluorescence quantum yield comparable to the analogs obtained previously.