Synthesis of 8-methyl-2-azainosine and related nucleosides

The synthesis of 6-methyl-7-(β-D-ribofuranosyl)imidazo[4,5-d]-v-triazin-4-one (8-methyl-2-azainosine ( 2) ) and 6-methyl-7-(β-D-glucopyranosyl)imidazo[4,5-d]-v-triazin-4-one ( 5 ) by diazotization of 5-amino-1-(β-D-ribofuranosyl)-2-methylimidazole-4-carboxamide ( 1 ) and diazotization of 5-amino-1-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl)-2-methylimidazole-4-carboxamide ( 3 ), followed by deacetylation of the resulting compound 4 , is described. The preparation of 6-methyl-5-(β-D-ribofuranosyl)imidazo[4,5-d]-v-triazin-4-one ( 10 ) and 6-methyl-5-(β-D-glucopyranosyl)imidazo[4,5-d]-v-triazin-4-one ( 11 ) by glycosylation of 6-methylimidazo[4,5-d]-v-triazin-4-one (8-methyl-2-azahypoxanthine, ( 7) ) is also described. Structural assignments were made on basis of analytical and ¹H-nmr and uv spectral data.     

Synthesis of novel pyridazine nucleosides

This paper presents the synthesis of novel pyridazine nucleosides containing the dicyanomethylene group and pyrrolo[2,3‐c]pyridazine nucleoside.     

Synthesis of mesoionic xanthine nucleosides

The synthesis of the first examples of Class II mesoionic xanthine nucleosides is described. Tri-O-acetylribofuranosylaminothiazole is cyclized by condensation with bis (2,4,6-tri-chlorophenyl) malonate and the resultant product is de-protected to yield $\text{anhydro}$ (8-β-$\text{D}$-ribofuranosyl-5-hydroxy-7-oxothiazolo [3,2-a] pyrimidinium hydroxide); the glucosyl derivative is prepared in a similar manner.     

Synthesis of 5-methylmercaptopyrimidine nucleosides

The synthesis of a series of new nucleosides, including ribo-, 2′-deoxyribo- and arabinofuranosides of 5-(S-methyl)mercapto-substituted uracil, 4-thiouracil, and cytosine is described. The synthetic methods employed include condensation reactions of the silylated pyrimidine with blocked sugar halides, as well as transformations of both the base and sugar moieties. The separated α and β anomers were identified by nmr spectra as well as by unambiguous synthetic routes or interconversions.     

Synthesis of novel bicyclic pyridazine nucleosides

The synthesis of some [6:6]- or [6:5]-fused bicyclic pyridazin-6-one nucleosides, starting from 4,5-dichloro-3-nitro(or amino) and 3-hydrazinopyridazin-6-one nucleosides is described.     

Synthesis of 8-amino-9-β-D-ribofuranosylpurin-6-thione and related 6-substituted-8-aminopurine nucleosides

Acetylation of 8-amino-9-β-D-ribofuranosylpurin-6-one (III), followed by chlorination of the tetraacetyl derivative 8-acetamido-9-(2,3,5-tri-O-aeetyl-β-D-ribofuranosyl)purin-6-one (IV) with phosphorus oxychloride yielded 8-aeetamido-6-ehloro-9-(2,3,5-tri-O-acetyl-β-D-ribofuranosyl)-purine (V). The 6-chloro substitutent of V was readily displaced with thiourea to give, after treatment with sodium methoxide 8-acetamido-9-β-D-ribofuranosylpurine-6-thione (VIII). Chlorination of 8-bromo-9-(2,3,5-tri-O-acetyl-β-D-ribofuranosyl)purin-6-one (IX) yielded 6,8-dichloro-9-(2,3,5-tri-O-acetyl-β-D-ribofuranosyl)purine (X), which underwent nucleophilic displacement with ethanolic ammonia selectively in the 8 position. The resulting 8-amino-6-chloro-9-β-D-ribofuranosylpurine (VII) was converted to 8-amino-9-β-D-ribofuranosylpurine-6-thione (I), 8-amino-6-methylthio-9-β-D-ribofuranosylpurine (II), and to 8-amino-6-hydrazino-9-β-D-ribofuranosylpurine (XI).     

Synthesis of nucleosides of substituted 3-hydroxypyrazoles

N-Glucoside analogs of the antibiotic pyrazofurine were obtained by fusion of 3-hydroxy-4-ethoxycarbonylpyrazole with tetra-O-acetyl-ß-D-ribofuranose in the presence of iodine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1512–1514, November, 1981.     

碳核苷的合成及生物活性研究

通过呋喃汞盐与溴代木糖的偶合，合成５个新碳核甙；经过元素分析，＾１ＨＮＭＲ，＾１３ＣＮＭＲ，ＭＳ，ＩＲ确定了它们的结构；并检验了其中两个化合物对α－及β－硫代葡糖苷酶的抑制活性。     

右旋肌醇甲醚唑类核苷类似物的合成

糖基部分中氧原子被亚甲基代替的碳环核苷是核苷类药物发展的一个重要方向.这类化合物表现出了比较宽的生物活性谱,特别是作为抗肿瘤[1]和抗病毒[2]药物的开发具有良好的前景.     

Synthesis and stability of exocyclic triazine nucleosides

Synthesis and stability studies of exocyclic amino triazine nucleosides were performed. Stability of the nucleosides was found to be dependent on triazine ring electron density, solvent, and pH. The nucleosides were found to be more stable when the triazine ring was electron deficient, in high pH aqueous solutions and in aprotic solvents.