The thermolysis of 3-azabicyclo[3,2,0]hept-6-enes

Derivatives of 3-methyl-3-azabicyclo[3,2,0]hept-6-ene-2,4-diones have been prepared by the ultraviolet irradiation of N-methylmaleimide and alkylacetylenes. The products were unchanged at 500°, but after reduction with lithium aluminium hydride they formed the corresponding 3-methyl-3-azabicyclo[3,2,0]hept-6-enes which at 500° rearranged smoothly to alkylbenzenes with elimination of methylamine. Addition of trichloroethylene to N-methylmalemide followed by dechlorination with zinc gave 6-chloro-3-methyl-3-azabicyclo[3,2,0]hept-6-ene-2,4-dione. When this was reduced with lithium aluminium hydride and the product heated at 500°, a low yield of N-methylaniline was obtained.