Synthesis and anti-bacterial activities of some novel pyrazolobenzothiazine-based chalcones and their pyrimidine derivatives

Journal article

A novel series of fifteen pyrimidine derivatives was prepared from pyrazolobenzothiazine-based chalcones by refluxing with guanidine hydrochloride. The starting materials 4-(3,4-dimethyl-5,5-dioxidobenzo[4,3-c][1,2]thiazin- 2(4-H)yl)phenyl)ethanone (2) or 4-(3,4-dimethyl-5,5-dioxidobenzo[ 4,3-c][1,2]thiazin-2(4-H)yl)benzaldehyde (3) were obtained by N-arylation of 3,4-dimethyl-2,4-dihydrobenzo[ e]pyrazolo[4,3-c][1,2]thiazine 5,5-dioxide (1) with 4-fluoroacetophenone or 4-fluorobenzaldehyde, respectively, using phase transfer catalyst, hexadecyl-tri-n-butylphsophonium bromide. The N-arylated product (2) or (3) was reacted in MeONa/MeOH with diversified aromatic aldehydes or ketones to furnish two series of newchalcones 4 and 5. Refluxing of 4 or 5 with guanidine hydrochloride in KOH (aq) and H 2O 2/EtOH yielded the 2-(4-(2-amino-6-arylpyrimidin- 4-yl)phenyl)3,4-dimethyl-2,4-dihydrobenzo[e] pyrazolo[4,3-c][1,2]thiazine-5,5- dioxide (6). The structures of chalcones (4 or 5) and corresponding pyrimidines (6) were confirmed with spectral data and elemental analysis. Several chalcones as well as pyrimidines showed marked activity against E. coli and S. aureus. © Springer Science+Business Media, LLC 2011.

Authors: Bukhari, M; Siddiqui, H; Ahmad, M; Hussain, T; Moloney, M

• Publication status: Published
• Journal: MEDICINAL CHEMISTRY RESEARCH
• Volume: 21
• Issue: 10
• Pages: 2885-2895
• Publication date: 2012-10-01
• DOI: 10.1007/s00044-011-9820-0
• EISSN: 1554-8120
• ISSN: 1054-2523
• Language: English
• Keywords: Pyrazolobenzothiazine; Pyrimidines; Anti-bacterial; Chalcones