Photochemical conversion of 3H-pyrazoles to cyclopropenes and 1, 2-diazabicyclo [2.1. 0] pent-2-enes

GL Closs, WA Boell, H Heyn, V Dev

Index: Closs,G.L. et al. Journal of the American Chemical Society, 1968 , vol. 90, p. 173 - 178

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Citation Number: 66

Abstract

Abstract: A series of six alkyl-substituted 3H-pyrazoles has been irradiated with ultraviolet light. In all cases ni-trogen elimination occurs and cyclopropenes are formed in variable yields. Using filtered light, ring opening was found to precede nitrogen elimination, and the corresponding diazoalkenes were formed. On irradiation of three fully alkylated 3 H- pyrazoles isomerization to 1, 2-diazabicyclo [2.1. O] pent-2-enes competes with nitrogen ...