Novel regioselective formation of S- and N-hydroxyl-alkyls of 5-(3-chlorobenzo[b]thien-2-yl)-3-mercapto-4H-1,2,4-triazole and a facile synthesis of triazolo-thiazoles and thiazolo-triazoles. Role of catalyst and microwave.

Regioselective alkylation of 5-(3-chlorobenzo[b]thien-2-yl)-4H-1,2,4-triazole (1) with hydroxy alkylating agents 2, 3, 13, and the 2,3-O-isopropylidene-1-O-(p-tolylsulfonyl)-glycerol (10) afforded the corresponding S-alkylated derivatives 6, 7, 11, and 14 under both conventional and microwave irradiation conditions; bentonite as a solid support gave better results, with no change in regioselectivity. A facile intramolecular dehydrative ring closure of 6, 7, 11, and 14 using K(2)CO(3) in DMF afforded the corresponding fused triazolo-thiazines and thiazolo-triazole 17-19. The isopropylidenes and acetyl derivatives of the products were prepared.

Studies on epimeric D-xylo-and D-lyxo-tetritol-1-yl-2-phenyl-2H-1,2,3-triazoles. Synthesis and anomeric configuration of 4-(alpha-and beta-D-threofuranosyl)-2-phenyl-2H-1,2,3-triazole C-nucleoside analogs.

Treatment of 4-(D-xylo-tetritol-1-yl)-2-phenyl-2H-1,2,3-triazole (1) with one mole equivalent of tosyl chloride in pyridine solution, afforded the C-nucleoside analog; 4-(beta-D-threofuranosyl)-2-phenyl-2H-1,2,3-triazole (2) in 55% yield, as well as the byproduct 4-(4-chloro-4-deoxy-D-xylo-tetritol-1-yl)-2-phenyl-2H-1,2,3-triazo le (4). Treatment of the epimeric 4-(D-lyxo-tetritol-1-yl)-2-phenyl-2H-1,2,3-triazole (6) with tosyl chloride in pyridine solution afforded the anomeric C-nucleoside analog; 4-(alpha-D-threofuranosyl)-2-phenyl-2H-1,2,3-triazole (7) in 29% yield, as well as the byproduct 4-(4-chloro-4-deoxy-D-lyxo-tetritol-1-yl)-2-phenyl-2H-1,2,3- triazole (9). Similar treatment of 1 and 6 with trifluoromethanesulfonyl chloride in pyridine solution afforded 2 and 7, respectively. The structure and anomeric configuration of these compounds were determined by acetylation, NMR, NOE, and circular dichroism spectroscopy, as well as mass spectrometry.

Synthesis and 1H NMR studies of 3-(D-erythro-glycerol-1-yl)-1H-pyrazolo[3,4-b]quinoxaline and its 7-chloro and 7-methyl analogues.

3-(D-erythro-Glycerol-1-yl)-1H-pyrazolo[3,4-b]quinoxaline and its 7-chloro and 7-methyl analogues (11 and 12) were prepared from the corresponding quinoxalines. The 7-substituted analogues 11 and 12 were obtained as the preponderant isomers, and the 6-substituted analogues as the minor isomers. The structure and position of the substituent were determined by 1H NMR studies. The effect of substitution on the chemical shift of other protons is discussed.