Characterization and biological evaluation of some novel pyrazolo[3’,4’:4,5]thieno[2,3-d]pyrimidin-8-ones synthesized via the Gewald reaction

Abstract

The synthesis of substituted pyrazolo[3’,4’:4,5]thieno[2,3-d]pyrimidin-8-ones (IIIa–j) from 5-amino-3-methyl-1H-thieno[3,2-c]pyrazole-6-carbonitrile (II) is described. The key compound II was synthesized from (5-methyl--2,4-dihydro-3H-pyrazol-3-ylidene)malononitrile I via the Gewald reaction. The synthesis of the title compounds IIIa–j was accomplished by condensation of II with different aromatic aldehydes. The newly synthesized heterocyles were characterized by elemental analysis, IR, 1H-NMR, 13C-NMR and mass spectroscopic investigation. All the newly synthesized compounds were evaluated for antimicrobial activity against a variety of bacterial strains.

Keywords

• pyrazolo[3’
• 4’:4
• 5]thieno[2
• 3-d]pyrimidin-8-ones
• carbonitrile
• Gewald reaction
• antimicrobial activity