Synthesis, X-ray Crystallographic Analysis and Bioactivities of α-Aminophosphonates Featuring Pyrazole and Fluorine Moieties

A series of novel -aminophosphonates containing pyrazole and fluorine moieties was designed and synthesized through ultrasonic-assisted condensation and solvent-free addition reactions. Their structures were verified by IR, 1H NMR, 13 C NMR and elemental analysis. The crystal structure of diethyl[(4-cyano-1H-pyrazol-3-ylamino)(3,5-difluorophenyl)methyl]phosphonate(4a, C15H17F2N4O3P) was determined by single-crystal X-ray diffraction. Compound 4a crystallizes in the triclinic system, space group P1 with a = 8.381(3), b = 10.103(5), c = 11.268(3) , = 83.772(19), = 74.726(19), = 70.964(18), V = 869.9(6) 3, Mr = 370.30, Dc = 1.414 g/cm3, Z = 2, F(000) = 384, = 0.200 mm-1, Mo Ka radiation( = 0.71073 ), the final R = 0.0487 and w R = 0.0823 for 1582 observed reflections with I > 2(I). X-ray diffraction analysis reveals that there are two planes in 4a, and the dihedral angle is 71.51. Two intermolecular hydrogen bonds and a face-to-face ··· stacking interaction are observed in the crystal structure. The compounds were evaluated for their antifungal, antiviral and antitumor activities, respectively. Among them, 4b, 4c, 4g and 4h exhibit good activities on Sclerotium rolfsii Sacc at 200 μg/m L, while 4b, 4c, 4f and 4g possess good anti-TMV activities at 500 μg/m L. Unfortunately, all of the compounds showed weak antitumor activities.