Photochemical Electron Transfer To Azines

Abstract

The excited-state reactions which serve as the focus of this study are based on single electron transfer (SET) from a notoriously good electron donor; triethylamine, to a variety of 1t-deficient aza­ heterocycles as phenylated pyridazine, pyrimidine, triazines and tetrazine. Products of photoreduction, photoreductive ring contraction (by extrusion of either a nitrogen atom or phenylmethine group) were obtained. Also products derived from the incorporation of solvent fragments are formed. Rationales of all processes involved are suggested. The results of photoreduction in neat triethylamine deviate from those obtained in neutral or acidic alcohol solution.