1,4-Cycloheptadienes: preparation and comparison of their proton magnetic resonance spectra with those of the corresponding cycloheptatrienes

A general route to 3-substituted cyclohepta-1,4-dienes is described in this paper. 7-Substituted cycloheptatrienes were used as starting materials and these were reacted with 4-phenyl-1,2,4-triazoline-3,5-dione to give 4 + 2 cycloaddition products of the norcaradiene form of the cycloheptatrienes. Catalytic reduction of these adducts gave 9-substituted 4-phenyl-2,4,6-triazatetracyclo[5.3.2.0 2,6 .0 8,10 ]dodeca-3,5-diones in good yield. Basic …