The key reagent 3,5-dichloro-4-pyridinecarbonitrile (1) was used to synthesize 4-aminomethylpyridine derivatives 3,5-disubstituted with various amino groups, very active as inhibitors of diamine oxidase. The study of the reaction allowed to discover conditions for the gradual substitution in good yields of the two chlorine atoms to give symmetrically and unsymmetrically disubstituted derivatives (3), or the substitution of the cyano group, or the formation of amidines. The reduction of the cyano to aminomethyl group in compounds (3) afforded the target bioactive products.