Temperature-dependent phototransposition chemistry of 1, 5-dimethylpyrazole and 1, 2-dimethylimidazole

RE Connors, DS Burns, EM Kurzweil…

Index: Connors, Robert E.; Burns, Douglas S.; Kurzweil, Edyth M.; Pavlik, James W. Journal of Organic Chemistry, 1992 , vol. 57, # 6 p. 1937 - 1940

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Citation Number: 9

Abstract

Permutation pattern analysis1i2 of the pyrazole-imidazole phototranspition indicates that the isomerization occurs by three distinct permutation patterns (P4, P& and P,) and hence by three distinct transposition mechanisms. The mechanisms which have been proposed for the phototransposition of pyrazole and similar five-membered heterocycles “are the electrocyclic ring closurenitrogen walk and the ring contraction-ring expansion ...