Antimicrobial and antitumor activity of n-heteroimmine-1,2,3-dithiazoles and their transformation in triazolo-, imidazo-, and pyrazolopirimidines Original Research Article

The reaction of Appelʹs salt with o-amino nitrile heterocycles 10–19 gave the corresponding 4-chloro-5-heteroimmine-1,2,3-dithiazoles 20–29 which were evaluated for their antibacterial, antifungal and antitumor activity. Although all these N-heteroimines were devoid of significant antibacterial activity, they showed significant antifungal activity. Moreover, the same derivatives represent highly versatile intermediates in heterocyclic synthesis, in fact the pyrazoleimino dithiazoles 20–26 can be converted in one step into 2-cyano derivatives of the corresponding 4-methoxy-pyrazolo[3,4-d]pyrimidines 30–35 by sodium methoxide in refluxing methanol. This provides a general and attractive route to 4-methoxy-6-cyano pyrazolo[3,4-d]pyrimidines from 1-substituted 5-amino pyrazoles 10–19 in two simple steps. Finally, the isosteric replacement of the pyrazole ring atoms to give the imidazole[3,4-d]pyrimidine and triazole [4,5-d] pyrimidine ring systems was examined.