178381-94-7

Upstream product

• 541-41-3 chloroformic acid ethyl ester 
• 169139-31-5 5-((2S,3S,4R,5R)-3,4-Bis-benzyloxy-5-benzyloxymethyl-tetrahydro-furan-2-yl)-1H-imidazole 
• 1972-28-7 diethylazodicarboxylate 
• 169139-30-4 (S)-4⁽⁵⁾-(2,3,5-tri-O-benzyl-D-ribosyl)imidazole 
• 169221-17-4 (R)-4⁽⁵⁾-(2,3,5-tri-O-benzyl-D-ribosyl)imidazole 
• 16838-89-4 2,3,5-tri-O-benzyl-D-ribofuranose 
• 169139-31-5 4(5)-2,3,5-tri-O-benzyl-β-D-ribofuranosylimidazole 

Downstream Products

• 689260-64-8 [4-(5-O-4,4'-dimethoxytrityl-β-D-ribofuranosyl)imidazol-1-yl]methyl 2,2-dimethylpropiolate 
• 689260-57-9 [4-(2,3,5-tri-O-benzyl-β-D-ribofuranosyl)imidazol-1-yl]methyl 2,2-dimethylpropiolate 
• 169139-31-5 4(5)-2,3,5-tri-O-benzyl-β-D-ribofuranosylimidazole 

Relevant academic research and scientific papers

Efficient and β-stereoselective synthesis of 4(5)-(β-D-ribofuranosyl)- and 4(5)-(2-deoxyribofuranosyl)imidazoles

A synthetic route to 4(5)-(β-D-ribofuranosyl)imidazole (1), starting from 2,3,5-tri-O-benzyl-D-ribose (5), was developed via a Mitsunobu cyclization. Reaction of 5 with the lithium salt of bis-protected imidazole afforded the corresponding 5-ribosylimidazole 7RS. Hydrolysis of 7RS gave a 1:1 mixture of diol isomers 8R and 8S having an unsubstituted imidazole. Mitsunobu cyclization of the mixture 8RS using N,N,N',N'-tetramethylazodicarboxamide and Bu3P exclusively afforded benzylated β-ribofuranosyl imidazole 9β in 92% yield, accompanied by α-anomer 9α, in a ratio of 26.3:1. The configuration of 9β was established by X-ray crystallography of ethoxycarbonyl derivative 10β. Reductive debenzylation of 9β over Pd/C was carried out, and the synthesis of 1 was attained from starting 5 in four steps and 87% overall yield. This synthetic methodology was extended to the synthesis of 4(5)-(2-deoxy-β-D-ribofuranosyl)imidazole (2). Mitsunobu cyclization of a 1:1 mixture of the corresponding diol isomers 14RS produced 15β and 15α in a ratio of 5.4:1. The synthesis of 2 was attained in a 59% overall yield from the starting 3,5-di-O-benzyl-2-deoxy-D-ribose (12). β-Stereoselective glycosylation in the key step is discussed and explained by intramolecular hydrogen bonding between an NH in the imidazole and the oxygen functional group in the sugar moiety.

Stereoselective Synthesis of the C-4 Linked Imidazole Nucleosides Using Modified Mitsunobu Reaction

A highly stereoselective synthesis of the novel 4-(β-D-ribofuranosyl)imidazole 5 was accomplished in 4 steps and 85 percent overall yield from protected D-ribose 1.Cyclization of the diol (RS)-3 having an intact imidazole by modified Mitsunobu reaction exclusively afforded benzylated β-ribofuranosylimidazole β-4a, accompanied by α-4a, in a ratio of 26:1.Reductive debenzylation completed the synthesis. 2'-Deoxy derivative 8 was also synthesized stereoselectively in the same manner.