The addition of glycosyl azides to benzyne

Ring contractions of 5-diazouracils. I. Conversions of 5-diazouracils into 1,2,3-triazoles by hydrolysis and methanolysis

“…A similar reaction of 23 gave only 5-methoxy-1,3 -dimeth-yluracil36 (26). The expected products, 18 and 1-methyl-1,2,3-triazole-4-N-methylcarboxamide (27) (prepared by treatment of 18 with methylamine), were used for a direct comparison (4H NMR) with the reaction mixture obtained from 23 and established that neither of these triazoles were present in detectable amounts.…”

“…The methanolysis of 11 gave a mixture of 12 (major product), 17, and methyl l-methyl-l,2,3-triazole-4-carboxylate (18), although a higher temperature (135°) was required for completion in 18 hr. A conversion of 12 to 1methyl-l,2,3-triazole-4-carboxylic acid (19) was accomplished by treatment with sodium hydroxide and esterification of 19 by treatment with methanol in the presence of dry hydrogen chloride gave 18.…”

“…Methanolysis of 5-Diazo-1 -methyluracil-6-methanolate (11) to Afford l-Methyl-l,2,3-triazole-4-carboxamide30 (12), Methyl l-Methyl-l,2,3-triazole-4-carboxylate (18), and Methyl Carbamate (17). 5-Diazo-l-methyluracil-6-methanolate28 (11, 2.58 g) was dissolved in dry methanol (20 ml).…”

“…(75 mg, from the methanolysis of 11) was added to a solution of methanol which had been previously saturated at -5°with ammonia (5 ml). The reaction vessel was tightly stoppered and the mixture was allowed to stand at room temperature for 18 hr. The solution was then evaporated to dryness in vacuo, the residue was triturated with methanol (1.5 ml) for 30 min, and the insoluble material was collected by filtration to give 12 (64.4 mg, 96%), mp 260-262°, uv Xmax (water) 210 nm (t 11300).…”

“…Methanolysis of 1 gave 2, methyl l-(d-D-ribofuranosyl)-l,2,3-triazole-4-carboxylate (16), and methyl carbamate (17). Methanolysis of 11 gave l-methyl-l,2,3-triazole-4-carboxamide (12), 17, and methyl 1 -methyl-1,2,3-triazole-4-carboxylate (18). Methanolysis of 7 gave methyl lV-(l,2,3-triazol-4-ylcarbonyl)carbamate (20) which established that these ring contractions proceeded via a N-l-C-2 bond cleavage.…”