Synthesis, Crystal Structure and Biological Activity of 5-(2-Methylpheny1)-1,3,4-oxadiazol-2(3H)-one Derivatives

3-Methyl-5-(2-methylphenyl)-1,3,4-oxadiazol-2(3H)-one (6) and N,N-diethy1-2-(2-methylbenzoyl)-hydrazinecarboxamide (7) were designed and synthesized from 5-(2-methylphenyl)-1,3,4-oxadiazol-2(311)-one (5) by substituting and ring-opening, respectively. The target compounds were confirmed by IR, H-1 NMR spectroscopy, MS, elemental analysis and single-crystal X-ray diffraction. Compound 6 (C10H10N2O2, M-r = 190.20) crystallizes in the triclinic system, space group P-1 with a = 7.4645(16), b = 10.868(2), c = 12.970(3) angstrom, alpha = 110.542(2), beta= 98.142(2), gamma=99.766(2)degrees, V= 947.7(3) angstrom(3), Z = 4, F(000) = 400, D-c = 1.333 g/cm(3), mu = 0.095 mm(-1), the final R 0.0550 and wR = 0.1483 for 2956 observed reflections with I > 2 sigma(I). Compound 7 (C13H19N3O2, M-r = 249.31) crystallizes in the monoclinic system, space group C2/c with a = 18.926(3), b = 12.1853(17), c = 14.740(2) angstrom, beta = 125.6380(10)degrees, V=2762.7(7) angstrom(3), Z = 8, F(000) = 1072, D-c = 1.199 g/cm(3), = 0.083 mm(-1), the final R = 0.0554 and wR = 0.1468 for 2395 observed reflections with I > 2 sigma-(I). The preliminary bioassay results indicate that compound 6 exhibits notable fungicidal activities against Fusarium graminearum, Botrytis cinerea, Rhizoctonia cerealis and Colletotrichum capsici at the concentration of 100 mu g/mL.