Facile regioselective synthesis and antimicrobial activity of heterocycle-phosphor esters

Several heterocycle-phosphor esters of moderate to good antimicrobial activity were efficiently obtained via applying different phosphorus reagents to the substrate 6-hydroxy-1,3-benzoxathiol-2-one. Benzothiophene-3-diethoxyphosphonates were obtained from the condensation reaction between the substrate and methyl, ethyl diethyl-phosphorylacetates, and diethyl cyanomethylenephosphonate. A coupling cyclization reaction of our substrate with vinyl- and allylphosphonates led to the corresponding benzoxathiaphosphinin-3(2H)-one oxides. On the other hand, an addition-cyclization reaction of dialkyl hydrogenphosphonates and tris(dialkylamino)phosphines with the oxathiolone substrate resulted in the formation of a series of 1,4,2-benzoxathiaphosphinin-3(2H)-one oxides. Screening results of antibiotic potency for the products were reported. .