P-D-ribofuranose

The conformational properties of furanose rings have received considerable attention in recent years because of the impact these properties may have in mediating biological processes . Most notable in this respect are the p-D-ribofuranose 1 and 2-deoxy-p-D-erythro-pentose 2 (Scheme 1) components of ribo- (RNA) and deoxyribonucleic (DNA) acids. It is well known that the furanose ring adopts specific shapes depending on its local structural environment in a biopolymer. For example, in tRNA, the... 

Ribitol is the reduction product of D-Ribose. P-D-Ribose-1 -phosphate is the phosphoric ester of the OH group on the anomeric carbon of P-D-ribofuranose. 

Vorbruggen s strategy, involving a Friedel-Crafts catalyzed silyl Hilbert-Johnson procedure, offered an alternative approach to the synthesis of 5-azacytidines.23 Utilizing these conditions, a related analog, 1-O-acetyl-2,3,5-tri-O-benzoyl-p-D-ribofuranose (14) was reacted with 2,4-bis(trimethylsilyloxy)-6-azauracil (15) and SnCl4 in 1,2-dichloroethane on a 10-kg scale. After hydrolysis of the reactive intermediate, 93% of recrystallized 6-azauridine-2,3, 5 -tri-(9-benzoate(16) was obtained. 

A similar reaction with l-0-acetyl-2,3,5-tribenzyl-p-D-ribofuranose affords P-ribosides exclusively (equation II). However, a-ribosides are formed preferentially if lithium perchlorate and 4 A molecular sieves are present. 

With D-ribose, the OH group used to form the five-membered furanose ring is located on C4. Cyclization yields two anomers at the new stereogenic center, which are called a-D-ribofuranose and p-D-ribofuranose. 

N -(2 -deoxy-ribonucleoside) and the 7-deazaguanine C8-(-2 -deoxyribonucleo-side), compounds (47) and (48), respectively. Compound (47) was obtained from the glycosylation of 8-aza-7-deaza-6-methoxypurine with an appropriately protected a-halogenose while (48) was prepared from the reaction of 7-deazaguanine with l-0-acetyl-2,3,5-tribenzoyl-P-D-ribofuranose in the presence of tin tetra-chloride. ... 

Cupps, T L, Wise, D S, Townsend, L B, A further investigation of the stannic chloride-catalyzed condensation reaction of 1-hexene and 1,2,3,5-tetra-O-acyl-p-D-ribofuranoses, Carbohydr. Res., 115, 59-73, 1983. 

Martin, O R, Mahnken, R E, Intramolecular C-arylation of benzylated sugars. The unexpected double C-glycosidation of tn i -O-m-methoxybenzyl-p-D-ribofuranose derivatives, J. Chem. Soc., Chem. Commun., 497-498, 1986. 

Figure 1.71 Main conformational preferences of 2 -deoxy-p-D-ribofuranose rings in polydeoxynucleotides (right). Cartoon illustration of these main envelope conformations (left) (illustrations from Sinden, 1994, Fig. 1.4).

Deoxy-D-ribose 2-Deoxy-P-D-ribopyranose 2-Deoxy-P-D-ribofuranose... 

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