A convenient synthesis, reactions and biological evaluation of novel pyrazolo[3,4-b]selenolo[3,2-e]pyrazine heterocycles as potential anticancer and antimicrobial agents

A novel series of 5-amino-6-substituted-3-methyl-1-phenyl-1H-pyrazolo[3,4-b]selenolo[3,2-e]pyrazines (3a-e) was synthesized by the reaction of the chloro pyrazolo[3,4-b]pyrazine carbonitrile1with selenium element in the presence of sodium borohydride and ethanol, followed by the reaction with alpha-halo alkylating agents to produce the selanyl-alkylated derivatives2a-e. The latter compounds underwentThorpe-Zieglercyclization upon heating with ethanolic sodium ethoxide solution to afford the target selenolopyrazolopyrazine compounds. The 5-amino-3-methyl-1-phenyl-1H-pyrazolo[3,4-b]selenolo[3,2-e]pyrazine-6-carboxamide (3b) was used as a versatile precursor for synthesis of new heterocyclic fused to the pyrazoloselenolopyrazine moiety namely: pyrimidine and imidazopyrimidine. Assignment of the chemical structures for the newly synthesized compounds was confirmed on the bases of elemental and spectral techniques including FT-IR,H-1 NMR,C-13 NMR, and mass spectra. Furthermore, certain compounds were screened for their antimicrobial activity which revealed remarkable activities against various pathogenic strains of bacteria and fungi. Alternatively, some of these compounds exhibited promising anticancer action against some colon and breast cancer cells.