Crystal structure of Diels-Alder cycloadduct formed from 1-(1,2,3-1H-benzotriazol-1-yl)-2-(4-methylphenyl)-2H-isoindole and dimethyl acetylenedicarboxylate.

The structure of the Diels-Alder cycloadduct formed from 2-(1,2,3-1H-benzotriazol-1-yl)-2-(p-tolyl)-2H-isoindole and dimethyl acetylenedicarboxylate was proved as 11-aza-1-(1,2,3-1H-benzotriazol-1-yl)-11-(4-methylphenyl)-tricyclo-[5.2.1.0(2.7)]undeca-2,4,6.9-tetraene-9,10-dioic acid dimethyl ester. The benzotriazole moiety was located as its 1-yl form, analogous to previous reports. The benzotriazole and the benzene (of tricyclo framework) planes were twisted with an angle of 115.83 degrees. Intramolecular close contacts between benzotriazole and ester are characteristic [N(3)...C(26), 2.754(3)A; N(3)...H(22), 3.26(4)A]. The shortest contact of N(3)...H(22) accounting for the rotation of the methyl group is estimated to be 3.10 A, which might be reasonable as C-H...N-type hydrogen bonding.