Acta Pharm. 63 (2013) 19-30

 

full paper

Original research paper

Synthesis and biological evaluation of some novel pyrazolopyrimidines incorporating a benzothiazole ring system

MOHAMMED AFZAL AZAM, LOGANATHAN DHARANYA, CHARU CHANDRAKANT MEHTA and SUMIT SACHDEVA

afzal9azam@hotmail.com

Department of Pharmaceutical Chemistry, J. S. S. College of Pharmacy, Ootacamund, India

Accepted September 28, 2012

 

In the present study, a series of benzothiazol derivatives 3a-l containing pyrazolo[3,4-d]pyrimidine moiety at the second position were synthesized and characterized by analytical and spectral data. The compounds were tested for their in vitro antimicrobial activity. Compounds 1-(1,3-benzothiazol-2-yl)-3-methyl-4-phenyl-1H-pyrazolo[3,4-d]pyrimidine (3a), 1-(1,3-benzothiazol-2-yl)-4-(4-chlorophenyl)-3-methyl-1H-pyrazolo[3,4-d]pyrimidine (3d) and 1-(1,3-benzothiazol-2-yl)-3-methyl-4-substituted phenyl-1H-pyrazolo[3,4-d]pyrimidines (3h-j) showed significant inhibitory activity against P. aeruginosa whereas compounds 1-(1,3-benzothiazol-2-yl)-4-(2-chlorophenyl)-3-methyl-1H-pyrazolo[3,4-d]pyrimidine (3b), 2-[1-(1,3-benzothiazol-2-yl)-3-methyl-1H-pyrazolo[3,4-d]pyrimidin-4-yl]phenol (3e), 1-(1,3-benzothiazol-2-yl)-4-(3,4-dimethoxyphenyl)-3-methyl-1H-pyrazolo[3,4-d]pyrimidine (3h), 4-[1-(1,3-benzothiazol-2-yl)-3-methyl-1H-pyrazolo[3,4-d]pyrimidin-4-yl]-N,N-dimethylaniline (3j) and 1-(1,3-benzothiazol-2-yl)-3-methyl-4-[2-phenylvinyl]-1H-pyrazolo[3,4-d]pyrimidine (3k) were found to be active against C. albicans. Some of these synthesized compounds were evaluated for their in vivo acute toxicity, analgesic, anti-inflammatory, and ulcerogenic actions. The tested compound 4-[1-(1,3-benzothiazol-2-yl)-3-methyl-1H-pyrazolo[3,4-d]pyrimidin-4-yl]-N,N-dimethylaniline (3j) exhibited maximum analgesic and anti-inflammatory activities. Compounds 1-(1,3-benzothiazol-2-yl)-3-methyl-4-(3-nitrophenyl)-1H-pyrazolo[3,4-d]pyrimidine (3i) and 3j showed a significant gastrointestinal protection compared to the standard drug diclofenac sodium.

 

Keywords: benzothiazoles, pyrazolo[3,4-d]pyrimidine, antimicrobial activity, anti-inflammatory activity