N-CYANOIMIDO-PHOSPHONYL/S-METHYL THIOCARBONATES: FACILE,USEFUL REAGENTS FOR THE SYNTHESES OF HETEROCYCLIC PHOSPHONATES

N-Cyanoimido-(O,O-dialkyl) phosphonyl/S-methyl thiocarbonates 2 were synthesized as facile, useful synthons for preparation of 1,3,5-triazine-, 1,2,4-triazole-, and 1,2,4-oxadiazole-phosphonates through cyclization reaction with various binucleophilic reagents. In addition, when 2a was treated with o-phenylenediamine, benzimidazole-2-yl phosphonate was obtained through addition–elimination reaction.