Synthesis, Crystal Structure and Anti-fungal/Anti-oomycete Activity of New Pyrazole-benzene Carboxamide Derivatives

Four novel pyrazole-benzene carboxamide derivatives 2a similar to 2d were synthesized and characterized by NMR, FIRMS spectral method and X-ray diffraction analysis, and were further conducted for screening the anti-fungal/anti-oomycete activity. Compound 2d crystallizes as monoclinic space group P2(1/c) with a = 42.260(4), b = 5.3751(4), c = 8.0129(9) angstrom, beta, = 92.958(10)degrees, V = 1817.7(3) angstrom(3), Z = 4, M-r = 385.41, D-c = 1.408 Mg/m(3), S = 1.087, mu = 0.773 mm(-1), F(000) = 808, the final R = 0.0763 and wR = 0.2136 for 2657 observed reflections (I > 2 sigma(I)). The preliminary antifungal assay indicates that the title compounds show fair to excellent antifungal/anti-oomycete activity toward four plant fungi and two crop oomycetes. Among them, compound 2b exhibits the strongest in vitro anti-B. cinerea effects (EC50 = 1.61 mg/L). In vivo test presents compound 2b displays considerable protective and curative effects to tomato fruits infected by B. cinerea. These results indicate that compound 2b would be potential fungicides leads for further development.

Automated summary

Four novel pyrazole-benzene carboxamide derivatives were synthesized and characterized. These compounds showed promising antifungal/anti-oomycete activity, with compound 2b exhibiting the strongest effects against B. cinerea and protecting tomato fruits from infection.