Synthesis and antimicrobial activities of some novel bis-pyrazole derivatives containing a hydrophosphoryl unit

Vilsmeier-Haack reaction conditions were applied on some methyl ketone aryl phosphonicdihydrazones to yield some interesting bis -pyrazole derivatives containing a hydro-phosphoryl unit. Bis -{4-formyl-3-aryl-1 H -pyrazol-1-yl}phosphine oxides (4a,b) were condensed with some nucleophiles such as aniline, phenacyltriphenylphosphonium bromide and 4-phenylthiosemicarbazide followed by treatment with thioglycolic acid, diethyl phosphite and/or acetic anhydride to yield a novel class of bis -pyrazoles containing sulfur and phosphorus derivatives. Most of the newly synthesized compounds were evaluated for their in vitro antimicrobial activities.