K. Rama Murthy

Synthesis, antimicrobial, and mosquito larvicidal activity of 1-aryl-4-methyl-3,6-bis-(5-methylisoxazol-3-yl)-2-thioxo-2,3,6,10b-tetrahydro-1H-pyrimido[5,4-c]quinolin-5-ones.

A series of 1-aryl-4-methyl-3,6-bis-(5-methylisoxazol-3-yl)-2-thioxo-2,3,6,10b-tetrahydro-1H-pyrimido[5,4-c]quinolin-5-ones (6a-h) have been synthesized by cyclization of ethyl-3-aryl-4-(2-chlorophenyl)-6-methyl-1-(5-methylisoxazol-3-yl)-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylates 4a-h with 3-amino-5-methylisoxazole 5. Compounds 4a-h were obtained by Biginelli reaction, by condensation of aromatic aldehyde 1, ethyl acetoacetate 2, and isoxazolyl thioureas 3 in a one-pot reaction catalyzed by ceric ammonium nitrite (CAN). Compounds 6a-h were tested for their antibacterial and antifungal activities against various bacterial and fungal strains. The results showed that these compounds exhibited good antibacterial and antifungal activity compared with that of standard antibiotics. Mosquito larvicidal activity of the newly synthesized compounds 6a-h is also studied against fourth instar larvae Culex quinquefasciatus. Some of the compounds are proved to be lethal for mosquito larvae.

Design, synthesis, antimicrobial, anti-inflammatory and analgesic activity of novel isoxazolyl pyrimido[4,5-b]quinolines and isoxazolyl chromeno[2,3-d]pyrimidin-4-ones

Novel series of 2-methyl-3-{3-methyl-5-[(E)-2-phenyl-1-ethenyl]-4-isoxazolyl}-3,4-dihydropyrimido[4,5-b]quinolin-4-ones 5 and 3-{3-methyl-5-[(E)-2-phenyl-1-ethenyl]-4-isoxazolyl}-3,4-dihydro-2H-chromeno[2,3-d]pyrimidin-4-ones 7 have been synthesized from isoxazolyl cyanoacetamide synthon 2. Compound 2 was obtained by reaction of 4-amino-3-methyl-5-styrylisoxazole 1 with ethyl cyanoacetate. Isoxazolyl pyrimido[4,5-b]quinolin-4-ones 5 were obtained from compounds 2 by condensation with o-nitro benzaldehyde followed by treatment with SnCl(2) and subsequent tandem N-acetylation and cyclodehydration with acetic anhydride. Compounds 2 were converted to isoxazolyl chromeno[2,3-d]pyrimidin-4-ones 7 by reaction with salicylaldehydes and subsequent cyclization with formaldehyde. Compounds 2-7 were characterized by IR, (1)H NMR, (13)C NMR, and Mass spectral data. The title compounds 5a-f and 7a-g were evaluated for their antimicrobial, anti-inflammatory and analgesic activity. Compounds 5d and 7e exhibited significant antimicrobial activity, potent anti-inflammatory and analgesic activities as that of standard drugs.

Synthesis and in vitro and in vivo anticancer activity of novel phenylmethylene bis-isoxazolo[4,5-b]azepines

A series of novel phenylmethylene bis-isoxazolo[4,5-b]azepine derivatives (10) have been synthesized from 3-methyl-4-nitro-5-styrylisoxazoles 6. The reaction of 6 with 3,5-dimethyl-4-nitroisoxazole (7) in piperidine afforded the Michael type adducts 8, which on treatment with different substituted chalcones in the presence of piperidine gave the Michael adducts 9. Compounds 9 underwent reductive cyclization on treatment with SnCl(2)-MeOH to afford the title compounds 10. Structure of these compounds was established on the basis of IR, (1)H NMR, (13)C NMR and Mass spectral data. The title compounds 10a-j were evaluated for in vitro and in vivo anticancer activity. Compound 10j exhibited good anticancer activity as that of standard drug Cisplatin.