Stereoselective Glycosylation of Nitrobenzimidazole Anions: Synthesis of 1,3-Dideaza-2′-deoxyadenosine and Related 2′-Deoxyribofuranosides
作者:F. Seela、W. Bourgeois
DOI:10.1055/s-1989-27429
日期:——
The synthesis of 1,3-dideaza-2′-deoxyadenosine (1) and related benzimidazole 2′-deoxyribonucleosides is described. Solid-liquid phase-transfer glycosylation of 5(6)-nitrobenzimidazole (9) or 4(7)-nitrobenzimidazole (15) in acetonitrile with 1-chloro-2-deoxy-3,5-bis-O -(4-methylbenzoyl)-α-D-erythro-pentofuranose (10) gave regioisomeric N-1 and N-3 β-D-2′-deoxyribofuranosides. The glycosylation yield, as well as the ratio of anomers and regioisomers, was altered by use of either tris[2-(2-methoxyethoxy)ethyl]amine (TDA-1) or [18]crown-6 as phase-transfer catalysts and potassium hydroxide or potassium carbonate as inorganic bases, respectively. Zemplén-deprotection and subsequent catalytic hydrogenation afforded the corresponding amino compounds 1, 2, 4, 5 and 7. Structural proof of anomeric and regio-isomeric compounds was made on the basis of 1H- and 13C-NMR spectroscopy. The benzimidazole 2′-deoxyribofuranosides 4 and 5 exhibit strong fluorescence at λmax =362 and 395 nm, respectively. 1,3-Dideaza-2′-deoxyadenosine (c1c3Ad, 1) is more stable in 1 N hydrochloric acid than dA (3a). Under alkaline conditions, compound 1 decomposes whereas the regioisomer 2 is stable. Compound 1 is no substrate for adenosine deaminase.
描述了 1,3-二氮杂-2′-脱氧腺苷(1)和相关苯并咪唑 2′-脱氧核苷的合成。5(6)-nitrobenzimidazole (9) 或 4(7)-nitrobenzimidazole (15) 与 1-chloro-2-deoxy-3,5-bis-O -(4-methylbenzoyl)-α-D-erythro-pentofuranose (10) 在乙腈中进行固液相转移糖基化,得到了 N-1 和 N-3 ²-D-2′-deoxyribofuranosides 异构体。分别使用三[2-(2-甲氧基乙氧基)乙基]胺(TDA-1)或[18]冠-6 作为相转移催化剂,以及氢氧化钾或碳酸钾作为无机碱,可改变糖基化产率以及异构体和雷公藤异构体的比例。通过臻普伦-脱保护和随后的催化氢化反应,得到了相应的氨基化合物 1、2、4、5 和 7。根据 1H 和 13C-NMR 光谱,证明了同分异构体和区域异构体的结构。苯并咪唑 2′-脱氧核糖核酸苷 4 和 5 分别在 Î "max =362 和 395 纳米波长处显示出强烈的荧光。1,3-二氮杂-2′-脱氧腺苷(c1c3Ad,1)在 1 N 盐酸中比 dA(3a)更稳定。在碱性条件下,化合物 1 会分解,而 Regioisomer 2 则很稳定。化合物 1 不是腺苷脱氨酶的底物。