Molecular Structures of the Reduced 1,2,4-Triazine Derivative and Its Reaction Product with Electron-deficient Acetylene

Abstract

Abstract The molecular structures of 3-methylthio-2-rnethyl-5,6-diphenyl-2,5-dihydro-1,2,4-triazine (1) and its reaction product with dimethyl acetylenedicarboxylate, 5,6-bis(methoxycarbonyl)-2-methyl-1-methylthio-4,8-diphenyl-2,3,7-triazabicyclo[3.3.0]octa-3,6-diene (2), were determined by the X-ray method. The former belongs to the triclinic system P\bar1, with Z=2, a=10.776(2), b=10.203(2), c=8.556(1) Å, α=105.44(2), β=104.94(2), and γ=60.31(2)°; the latter belongs to the orthorhombic system Pca21 with Z=4, a=18.166(2), b=7.444(2), and c=16.080(2) Å. Both structures were solved by the direct method. The final R-factors are 0.075 for 1 and 0.048 for 2. In Compound 1 the dihydrotriazine ring is in the boat form, while in Compound 2 both of the cis-fused five-membered rings are in the envelope form.