The present article describes a facile one-pot synthesis of a series of eight pyrazolo[3,4-d]pyrimidines 4a-h which were evaluated for their in-vitro antibacterial activity against Mycobacterium tuberculosis H37Rv using the Alamar-Blue susceptibility test and the activity expressed as the minimum inhibitory concentration (MIC) in mg/mL. The compounds 4b, 4c, 4d, and 4g exhibited the best results (1.2 microg/mL) when compared with first-line drugs such as isoniazid (INH) and rifampicin (RIP). Therefore, this class of compounds could be a good starting point to develop new lead compounds in the treatment of multidrug-resistant tuberculosis.

Fused pyrimidine derivatives R 0515 Facile One-Pot Synthesis and Antimycobacterial Evaluation of Pyrazolo[3,4-d]pyrimidines. -All title compounds (IV) (8 examples) display significant antimycobacterial activity. Derivatives (IVb)-(IVe) exhibit the best results when compared with first-line drugs such as isoniazid and rifampicin. -(TRIVEDI, A.; DODIYA, D.; SURANI, J.; JARSANIA, S.; MATHUKIYA, H.; RAVAT, N.; SHAH*, V.; Arch. Pharm. (Weinheim, Ger.) 341 (2008) 7, 435-439; Dep. Chem., Saurashtra Univ., Rajkot 360 005, India; Eng.) -A. Forchert 44-167

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, 1 H-NMR, 13 C-NMR and mass spectroscopic investigation. All the newly synthesized compounds were evaluated for antimicrobial activity against a variety of bacterial strains.