GENERATION OF ETHYL METATHIOPHOSPHATE BY THERMAL FRAGMENTATION OF O-ETHYL N-SUBSTITUTED PHOSPHORAMIDOTHIOATES

O-Ethyl N-1-adamantylphosphoramidothioate was synthesized and found to fragment on heating in inert solvents to form the pyrophosphate AdNHP (S)(OEt)OP(S)(OEt)OH. The proposed mechanism involves an elimination o f the amine portion with release of ethyl metathiophosphate (EtOP(S)O) , as was confirmed in previous work for the comparable structure with oxygen. This transient compound then phosphorylates the starting phosp horamidothioate. O-Ethyl N,N-diethylphosphoramidothioate was also synt hesized, and while it gave a similar pyre compound on heating, the rea ction mixture was more complex. Both phosphoramidothioates, however, s erved effectively as thiophosphorylating agents toward alcohols, a sil anol, and the silanol groups on the surface of silica gel. Exploratory experiments showed that these phosphoramidothioates also could thioph osphorylate the OH group of a monoester of phosphoric acid, as well as that of phosphinic acids, forming anhydrides with the partial structu re