Synthesis and antibacterial activity of novel cinnoline-isoxazole derivatives

Synthesis of novel sulphamethoxazole derivatives and exploration of their anticancer and antimicrobial properties

“…The interaction of β-alanine 2 with urea or potassium thiocyanate in refluxing acetic acid followed by the acidification of the reaction mixture with hydrochloric acid to cyclize the intermediate ureido or thioureido acid resulted in 1-aryl-5,6-dihydrouracil 5 and its 2-thio analogue 6, respectively. In the 1 H NMR spectra, the additional peaks at 11.45 ppm (5) and 11.55 ppm (6) were assigned to the protons of NH groups of the cyclic fragment. The 13 C NMR spectrum of compound 5 showed resonances at 157.48 and 170.42 ppm, which were attributed to 2C = O of the formed cycle, as well as in the spectrum of compound 6 spectral lines at 170.48 and 179.62 (6) ppm confirmed a ring bearing the carbonyl and thiocarbonyl groups.…”

“…In the 1 H NMR spectra, the additional peaks at 11.45 ppm (5) and 11.55 ppm (6) were assigned to the protons of NH groups of the cyclic fragment. The 13 C NMR spectrum of compound 5 showed resonances at 157.48 and 170.42 ppm, which were attributed to 2C = O of the formed cycle, as well as in the spectrum of compound 6 spectral lines at 170.48 and 179.62 (6) ppm confirmed a ring bearing the carbonyl and thiocarbonyl groups. To isolate intermediate 6a a solution of thioxotetrahydropyrimidinone 6 in 5% sodium hydroxide was stirred at room temperature for 24 hours then filtered off and the filtrate was acidified with glacial acetic acid to pH 6-7.…”

“…Isoxazole derivatives being an entity of this group of compounds make a significant contribution displaying a wide range of important therapeutic properties viz. anti-inflammatory, anti-ulcer [ 2 ], anti-cancer [ 3 , 4 ], anti-tubulin [ 5 ], antibacterial [ 6 , 7 ], antioxidant [ 8 , 9 ], immunoregulatory [ 10 ], antiplatelet [ 11 ], antifungal [ 12 ], anticonvulsant [ 13 ] and many others [ 14 – 16 ]. The substitution and modification of isoxazole structure provided a large library of biologically active compounds useful for the development of therapeutic agents with higher potency and lower toxicity [ 17 ].…”

An overview of metal-free synthetic routes to isoxazoles: the privileged scaffold

“…Interestingly, among all the derivatives, compound 122k showed the best result against Pseudomonas aeruginosa . 41 …”

Design, synthesis and bioactivity of myricetin derivatives for control of fungal disease and tobacco mosaic virus disease

“…19 Related studies have revealed that compounds containing isoxazole structures exhibit a wide range of biological functions. It not only has good anti-cancer 20 bactericidal, 21 antiviral 22,23 and anti-inflammatory, 24 biological activities in the field of medicine, but also shows excellent antifungal, 25 insecticidal, 26 herbicidal 27 and other biological activities in the field of pesticides.…”