Phenylguanidine carbonate salt may be used in the preparation of the following bioactive compounds:(E)-methyl 2-(2-((6-cyclopropyl-2-(phenylamino)pyrimidin-4-yloxy)methyl)phenyl)-3-methoxyacrylatecyprodinil5,6-dihydropyrido[2,3-d]pyrimidineethyl 1-methyl-8-(phenylamino)-4,5-dihydro-1H-pyrazolo[4,3-h]quinazoline-3-carboxylate2-(phenylamino)-4-(trifluoromethyl)-1,6-dihydropyrimidine derivatives