Reaction of 3,4,6-tri-O-acetyl-2-deoxyglucopyranosyl bromide (1) with silylated 5-benzyluracil and subsequent ammonolysis afforded α- and β-anomers of 5-benzyl-1-(2-deoxy-D-glucopyranosyl)uracil (2 and 3). Under catalysis with tin tetrachloride, silylated 5-benzyluracil reacted with 1-O-acetyl-2,3,5-tri-O-benzoyl-D-ribofuranose to give 2',3',5'-tri-O-benzoyl-5-benzyluridine (10), which was converted into the 4-thio derivative 11 by reaction with Lawesson reagent. Debenzoylation of compound 11 afforded 5-benzyl-4-thiouridine (12), whereas its reaction with methyl iodide and deblocking gave 4-methylthiopyrimidine nucleoside 14. Amonolysis of derivative 12 at elevated temperature afforded 5-benzylcytidine (15). This reacted with thionyl chloride at room temperature to give cyclic sulfite 16 which on heating at 100 °C in dimethylformamide was converted into 5-benzyl-2,2'-cyclocytidine (17). Mild alkaline hydrolysis of compound 17 afforded 1-(β-D-arabinofuranosyl)-5-benzylcytosine (18). With boiling thionyl chloride, compound 15 formed 2',3'-cyclic sulfite 19 which on alkaline hydrolysis gave 5-benzyl-5'-chloro-5'-deoxycytidine (20). Compound 20 was reduced with tributylstannane to 5-benzyl-5'-deoxycytidine (21). Reaction of silylated 5-benzyluracil with 2-deoxy-3,5-bis(O-p-toluoyl)-D-ribofuranosyl chloride, catalyzed with mercury(II) bromide, afforded 5-benzyl-2'-deoxy-3',5'-bis(O-p-toluoyl)uridine (22) and its α-anomer 23. With Lawesson reagent, compound 22 gave 5-benzyl-4-thiouracil derivative 24 which was ammonolyzed to give 5-benzyl-2'-deoxycytidine (25). Analogously, compound 23 was converted into 5-benzyl-2-deoxy-α-cytidine (27). 5'-O-Benzoyl-5-benzyluridine (29) was converted into the 2,2'-anhydro derivative 30 which on reaction with hydrogen chloride afforded 3'-chloro-3'-deoxynucleoside 31. This compound was reduced with tributylstannane and the obtained 2'-deoxynucleoside 32 on treatment with thionyl chloride gave a mixture of erythro- and threo-3'-chloro-2',3'-dideoxynucleosides (33 and 34, respectively) which were reduced to 5'-O-benzoyl-5-benzyl-2',3'-dideoxyuridine (35). Compound 35 reacted with Lawesson reagent under formation of 4-thiouracil derivative 36 and this was deblocked to 5-benzyl-4-thio-2',3'-dideoxyuridine (37). On heating with ammonia, compound 37 was converted into 5-benzyl-2',3'-dideoxycytidine (38). Reaction of 4-thiouracil derivative with methyl iodide and subsequent hydrazinolysis afforded 4-hydrazino derivative 40 which was heated with silver oxide in ethanol to give a mixture of anomeric 5-benzyl-1-(2,3-dideoxyribofuranosyl)-2(1H)-pyrimidinones (42).
3,4,6-三-O-乙酰基-2-脱氧葡萄糖吡喃溴化物(1)与硅化的5-苄基尿嘧啶反应,随后进行氨解作用,得到5-苄基-1-(2-脱氧-D-葡萄糖吡喃基)尿嘧啶的α-和β-异构体(2和3)。在锡四氯化物催化下,硅化的5-苄基尿嘧啶与1-O-乙酰基-2,3,5-三-O-苯甲酰-D-核糖呋喃糖发生反应,得到2',3',5'-三-O-苯甲酰-5-苄基尿苷(10),它通过与Lawesson试剂反应转化为4-硫衍生物11。化合物11的去苯甲酰化得到5-苄基-4-硫尿苷(12),而它与甲基碘和去保护处理后得到4-甲硫嘧啶核苷(14)。将衍生物12在高温下进行氨解作用得到5-苄基胞嘧啶(15)。这与亚硫酰氯在室温下反应形成环状亚硫酸酯(16),然后在二甲基甲酰胺中加热至100°C,转化为5-苄基-2,2'-环胞嘧啶(17)。化合物17的温和碱水解得到1-(β-D-阿拉伯呋喃糖基)-5-苄基胞嘧啶(18)。用沸腾的亚硫酰氯处理化合物15形成2',3'-环状亚硫酸酯(19),在碱性水解后得到5-苄基-5'-氯-5'-脱氧胞嘧啶(20)。化合物20经三丁基锡烷还原得到5-苄基-5'-脱氧胞嘧啶(21)。硅化的5-苄基尿嘧啶与2-脱氧-3,5-双(O-p-对甲苯酰)-D-核糖呋喃糖氯化物,汞(II)溴化物催化,得到5-苄基-2'-脱氧-3',5'-双(O-p-对甲苯酰)尿苷(22)及其α-异构体23。用Lawesson试剂,化合物22得到5-苄基-4-硫尿嘧啶衍生物24,氨解后得到5-苄基-2'-脱氧胞嘧啶(25)。类似地,化合物23转化为5-苄基-2-脱氧-α-胞嘧啶(27)。5'-O-苯甲酰-5-苄基尿苷(29)转化为2,2'-脱水衍生物30,与氯化氢反应得到3'-氯-3'-脱氧核苷(31)。该化合物经三丁基锡烷还原,得到2'-脱氧核苷(32),经亚硫酰氯处理得到一混合物,包括erythro-和threo-3'-氯-2',3'-脱氧核苷(33和34),进一步还原为5'-O-苯甲酰-5-苄基-2',3'-脱氧尿苷(35)。化合物35与Lawesson试剂反应,形成4-硫尿嘧啶衍生物36,解保护后得到5-苄基-4-硫-2',3'-脱氧尿苷(37)。与氨一起加热,化合物37转化为5-苄基-2',3'-脱氧胞嘧啶(38)。4-硫尿嘧啶衍生物与甲基碘反应,随后进行酰肼解作用得到4-叠氮衍生物40,它与乙醇中的氧化银加热形成5-苄基-1-(2,3-脱氧核糖呋喃基)-2(1H)-嘧啶酮异构体的混合物(42)。