Ribitol synthesis

Riboflavin, or vitamin B2, is a constituent and precursor of both riboflavin 5 -phosphate, also known as flavin mononucleotide (FMN), and flavin adenine dinucleotide (FAD). The name riboflavin is a synthesis of the names for the molecule s component parts, ribitol and flavin. The structures of riboflavin. 

D-Ribono-1,4-lactone (1) readily condenses with acetone, under acidic catalysis with mineral acids or anhydrous copper sulfate, to give 2,3-0-isopropylidene-D-ribono-1,4-lactone (16a), which was employed for the synthesis of 5-deoxy and 5-0-substituted derivatives of D-ribono- 1,4-lactone and D-ribitol (24). Acid removal of the 1,3-dioxolane protecting group gave products having probable inhibitory activity of arabinose 5-phosphate isomerase (25). Other applications of 16a for the synthesis of natural products will be discussed later. 

The borohydride reduction-periodate cleavage applied to 2,3-O-isopro-pylidene-D-ribono- 1,4-lactone (16a) led to L-erythrose (30). The method was also employed (31) for the synthesis of D-erythrose, starting from an Obenzylidene-D-ribonolactone. However, in this case, the structural assignments for the intermediate compounds must be revised, as the starting material formulated as 3,5-O-benzylidene-D-ribono-1,4-lactone (2) was, as discussed previously in this section, the 3,4-0-benzylidene-D-ribono-1,5-lactone (3a). Therefore, the correct structure for the product described as 3,5-O-benzylidene-D-ribitol (20, not isolated) would be 3,4-O-benzylidene-... 

J. Di, B. Rajanikanth, and W. A. Szarek, Fluorinated l,5-dideoxy-l,5-iminoalditols Synthesis of l,5,6-trideoxy-6-fluoro-l,5-imino-D-glucitol (l,6-dideoxy-6-fluoronojirimycin) and 1,4,5-trideoxy-4-fluoro-l,5-imino-D-ribitol (l,2,5-trideoxy-2-fluoro-l,5-imino-L-ribitol), J. Chem. Soc., Perkin Trans. 1 (1992)2151-2152. 

Synthetic ribitol phosphate polymer, unlike teichoic acid in a wall, is readily extracted from the particulate enzyme or membrane preparation by treatment with phenol.18 Similarly, teichoic acid synthesized by intact cells in the presence of penicillin is only loosely attached to the wall,111 and it may be significant that, in each case, synthesis of teichoic acid has occurred without the simultaneous synthesis of glycosaminopeptide. It is now known that, in the normal wall, teichoic acid and glycosaminopeptide are attached to each other, and it has been suggested that the low activity of cell-free synthetase is due to the absence of suitable acceptor molecules of glycosaminopeptide. This possibility could account for the ease of removal of teichoic acid formed when simultaneous synthesis of glycosaminopeptide was not possible. 

The poly (ribitol phosphate) synthetase and poly (glycerol phosphate) synthetase are inhibited by vancomycin, novobiocin, and Crystal Violet. Other antibiotic substances which interfere with cell-wall synthesis (such as bacitracin, ristocetin, and streptomycin) are almost without effect on the isolated synthetases, and penicillin is inhibitory at high concentrations only. Moreover, penicillin, vancomycin, and bacitracin do not markedly inhibit synthesis of cell-wall glycosaminopeptide in vitro, although the synthetical activity of extracts of cells which have been pretreated with these antibiotics is lowered.Convincing evidence that the primary site of inhibition by antibiotics is the biosynthesis of cell-wall material has been obtained only for the penicillins and cycloserine, and it appears that the action of even those antibiotics may be more complex than was originally supposed. 

Baddiley and coworkers42> obtained 4-O-a-D-glucopyranosyl-D-ribitol (18), as the chain fragment of a TA extracted from Lactobacillus arabinosus. The synthesis involved several steps, as follows ... 

A similar approach was applied in the synthesis of a- and (D-anomers of 4-O-d-glucosaminyl-D-ribitol 21, the fragments of the TA extracted from Staphylococcus... 

A new synthetic approach to D-ribose has recently been made by Sowden.43 In this procedure 4,6-benzylidene-D-glucose (X) was reduced catalytically to 4,6-benzylidene-D-glucitol (XI) which was then oxidized with sodium metaperiodate to 2,4-benzylidene-D-erythrose (XII). Condensation of this latter compound with nitromethane gave a mixture of epimeric, crystalline, substituted C-nitro alcohols, 3,5-benzylidene-1-desoxy-l-nitro-D-arabitol and 3,5-benzylidene-l-desoxy-l-nitro-D-ribitol (XIII). After separation, the appropriate isomer was hydrolyzed to 1-nitro-l-desoxy-D-ribitol (XIV) which, in the form of its sodium salt was decomposed directly to D-ribose (XV), isolated as its benzylphenyl-hydrazone. This synthesis is of interest in that it may be used to obtain D-ribose labeled at carbon 1 with C.14... 

Park and Strominger noticed the accumulation of a C3didine derivative in cultures of Staphylococcus aureus which had been inhibited by chloramphenicol, penicillin, or Crystal Violet. This cytidine derivative has been identified by Baddiley s group as cytidine ribitol pyrophosphate. Since these inhibitors affect the cell-wall synthesis, the data lend support to the belief that the cytidine compound is involved in the biosynthesis of a cell-wall constituent, and a likely candidate would be ribitol teichoic acid. 

The usefulness of the Amadori rearrangement in chemical synthesis was demonstrated by Weygand who showed how n-arabinose, instead of the more expensive n-ribose, could be used in the preparation of riboflavin. Condensation of n-arabinose with 3,4-dimethylaniline in the presence of an acid catalyst gave the Amadori rearrangement product, 1-deoxy-l-(3,4-dimethylanilino)-D-er2/ liro-pentulose (not isolated), which could be catalytically hydrogenated in alkaline solution to produce the desired intermediate, l-deoxy-l-(3,4-dimethylanilino)-D-ribitol. Also, Amadori re-... 

Varela and Zunszain [18] synthesized 4-thio analogs 16 of D-ribonolactone as well as L-lyxonolactone (Figure 9.5). Approaches to l,4-anhydro-4-thio-D-17 and -L-ribitol were recently described by Altenbach and coworkers [19,20]. l,4-Anhydro-4-thio-D-arabinitol was employed in the synthesis of a potential inhibitor of glycosyl transferases [21]. Access to 4-thiopentonolactones has also been provided, for example, by Dominguez and Owen [22]. 

A universal support for oligonucleotide synthesis has been described (136). The support was synthesised from 1,4-anhydro-D-ribitol. ... 

Preparation. D-m7//ro-2-Pentulose (12) has been synthesized from D-arabinose by isomerization with pyridine, followed by isolation as the crystalline (o-nitrophenyl)hydrazone.54 Enzymic synthesis provides D-eiyf/tro-2-pentulose by oxidation of ribitol with NAD-dependent ribitol dehydrogenase55 or from D-arabinitol with D-arabinitol dehydrogenase.56... 

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