A practical synthesis of 1,4-anhydro-4-thio-D-ribitol (5)
via 1,4-dibromo-1,4-dideoxy-2,3,5-tri-O-benzyl-L-lyxitol (12) is described. This method reduced our previous eleven step procedure starting from D-ribose by three steps. The Pummerer reaction of 1,4-anhydro-2-O-(2,4-dimethoxybenzoyl)-3,5-O-(1,1,3,3-tetraisopropyldisiloxane-1,3-diyl)-4-sulfinyl-D-ribitol (6) in the presence of N4-benzoylcytosine afforded the 4â²-thiocytidine derivative 7b on a large scale. Starting with the resulting 7b, 1-(3-C-ethynyl-4-thio-β-D-ribofuranosyl)cytosine (4; 4â²-thioECyd), of which the 4â²-oxo congener ECyd (3) is a new type of potent antineoplastic nucleoside developed in our group, was synthesized via elaborate protection and deprotection procedures, and successive reaction with cerium trimethylsilylacetylide. X-Ray crystal structures of 4â²-thioECyd (4) and ECyd (3) are presented in this paper. Although striking differences in bond lengths and angles were observed in C1â²âS4â² and C4â²âS4â², and C4â²âS4â²âC1â², the overall structures of each compound, including the sugar puckering mode and the syn/anti conformation around the glycosyl bond, were similar.
1,4-脱
水-4-
硫代-
D-核糖醇的实用合成 (5)
描述了1,4-二
溴-1,4-二脱氧-2,3,5-三-O-苄基-L-来
木糖醇(12)。该方法将我们之前从
D-核糖开始的十一个步骤减少了三个步骤。 1,4-脱
水-2-O-(2,4-二
甲氧基苯甲酰基)-3,5-O-(1,1,3,3-四异丙基二
硅氧烷-1,3-二基)-4-亚磺酰基-的Pummerer反应
D-核糖醇 (6) 在 N4-苯甲酰
胞嘧啶存在下大规模提供 4α-
硫胞苷衍
生物 7b。从所得的 7b 开始,1-(3-C-
乙炔基-4-
硫代-β-D-
呋喃核糖基)
胞嘧啶 (4; 4-thio
ECyd),其中 4-oxo 同系物
ECyd (3) 是我们课题组开发的一种新型强效抗肿瘤核苷,是通过精心的保护和脱保护程序,以及与三甲基甲
硅烷基乙酰化
铈的连续反应合成的。本文介绍了 4-thio
ECyd (4) 和
ECyd (3) 的 X 射线晶体结构。尽管在 C1-2-S4-2 和 C4-2-S4-2 以及 C4-2-S4-S4-C1-2 中观察到键长和角度的显着差异,但每种化合物的整体结构,包括糖褶皱模式和糖基键周围的顺式/反式构象,都是相似的。