Guanidines based on tryptamine and histamine in reactions with electrophiles

Reactions of 4,6-dimethylpyrimidin-2-ylcyanamide with tryptamines and histamine gave the corresponding disubstituted guanidines. The molecular parameters of the products were calculated using GAUSSIAN 03 software package. The direction of electrophilic attack on these compounds was predicted on the basis of the geometric shape of their highest occupied molecular orbital (HOMO) and molecular electrostatic potential (MEP) maps. Acyl, carbamoyl, and cyclic derivatives were obtained, whose structure was consistent with the results of quantum-chemical calculations.