A simple strategy for the synthesis of the hitherto unreported 3-arylazo-4-phenyl- [1,2,4]triazepino[2,3-a]quinazoline-2,7(1H)-diones is described. Spectral data indicated that the studied compounds exist predominantly in the hydrazone tautomeric form. The antimicrobial activity of the newly synthesized compounds was also evaluated. The results indicated that some of these compounds have moderate activity towards bacteria.
Condensation of 7-ethyl-8-hydrazinotheophylline 1 with aldohexoses 2-4 and aldopentoses 5,6 by heating in an aqueous ethanolic solution and in the presence of a catalytic amount of acetic acid gives the corresponding hitherto unknown aldehydo-sugar (7-ethyl-8-theophyllinyl)hydrazones 7-11. The structures of the sugar hydrazones 7-11 were confirmed by their elemental analyses and spectral (IR, 1 H NMR and FAB-MS) data. Acetylation of the sugar hydrazones 7-11 with acetic anhydride in pyridine at room temperature gave the corresponding poly-O-acetyl derivatives 12-16. Attempted dehydrogenative cyclization of the products 7-11 and 12-16 using various conditions did not afford the corresponding acyclo C-nucleosides (R= sugar or R`= acetylated sugar) 18. On the other hand, the reaction of 7-11 or 12-16 with bromine in acetic acid and sodium acetate afforded 8-bromo-7-ethyltheophylline 17. The structural elucidation of products is reported and also some of the products were screened for their antimicrobial activity.
1,2,4]Triazolo[5,1-b]-and [1,2,4]triazino [3,2-b] quinazolines have been ribosylated by coupling with 1-O-acetyl-2,3,5-tri-Obenzoyl--D-ribofuranose and by using the silylation method, followed by debenzoylation by methanolic sodium methoxide to afford the corresponding free N-nucleosides. Nucleosides obtained have been identified by their spectral analysis. From the UVvisible and fluorescence studies of some nucleosides synthesized, it is found that they have fluorescence properties. 6 ) 7.20 (d, 2H, aromatic protons, = 8.0 Hz), 7.70 (d, 2H, aromatic protons, = 8.0 Hz), 7.90 (m, 5H, aromatic protons), 11.50 (s, 1H, NH); MS (m/z) = 262 (M + , 70%). Anal. Calcd for C 15 H
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