V-Triazolines. Part XXI. Spiro[bicyclo[2.2.1]hept-2-ene[5.4']1',2',3'-triazole] derivatives from cyclopentadiene and 5-amino-4-methylene-v-triazolines

1R*, 4R*, 5S*, 5'S*-5'-Amino-1'-(4-nitrophenyl)-4',5'-dihydrospiro[bicyclo [2.2. 1]hept-2-ene[5.4]-1',2',3'-triazoles]2 have been obtained both by ?4 +2]-cycloaddition of cyclopentadiene to amino-methylene-1-(4-nitrophenyl)-4,5-dihydro-v-triazoles 1 and by [3+2]-cycloaddition of 4-nitrophenylazide to 5-aminomethylene-2-norborenes 4. The configuration has been fully established by X-ray crystallographic analysis. The course of the cycloaddition and the thermal behaviour of 2 are discussed.