The reactions ofN-methylated oxopurines with phosphorus chlorides, resulting in the formation of highly reactive amidochloride compounds (amidochlorides or adducts), are described. Two isomeric series of C(2)- or C(6)-substituted oxopurine derivatives as well as C(6)- or C(2)-iminopurines can be obtained from such compounds.The properties and characteristics of the compounds, their structures, and the demethylation reactions of the amidochlorides and the adducts, accompanied by the elimination of methyl chloride, are discussed.The bibliography includes 76 references