Reactions with Amines, Imines, Nitroso Oxide, and Protic Solvents

Reactions with Amines, Imines, Nitroso Oxide, and Protic Solvents 

Data on photophysics and photochemistry of intramolecular stilbene-amine exciplexes and reactions have been reported [34]. The obtained data indicated that the photophysical and photochemical behavior of a series of traws-(aminoalkyl) stilbenes in which a primary, secondary, or tertiary amine is appended to the stUbene ortho position with a Me, Et, or Pr linker. The tertiary (aminoalkyl) stilbenes formed fluorescent exciplexes and underwent trans cis isomerization but failed to undergo intramolecular N—H addition. The secondary (aminoalkyl)stilbenes did not form fluorescent exciplexes but underwent the addition to the stilbene double bond. Intramolecular reactions were highly selective, providing an efficient method for the synthesis oftetrahydrobenzazepines. Direct irradiation of the primary (aminoalkyl) stilbenes resulted only in trans-cis isomerization, while irradiation in the presence of the electron acceptor p-dicyanobenzene resulted in regioselective intramolecular N—H addition to the stilbene double bond. 

Photochemical reactions of nitroso oxides at low temperatures with stilbenes have been reported [35]. Several singlet nitroso oxides were generated by the thermal reaction of triplet nitrenes with triplet oxygen at 95 K in 2-methyltetrahydrofuran. After photolysis of the nitroso oxides at 77 K, the formation of intermediates was observed. From spectroscopic and kinetics data, the authors postulated the formation 

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