Ribitol derivatives, synthesis

The preparation of some glycosylated ribitols as useful building blocks for the synthesis of certain teichoic acids has been described. The 1,6-anhydro-P-D-talopyranose (13), a key intermediate, is readily accessible from l,6-anhydro-23-< -(S)-benzylidene-p-D-mannopyranose. Thus coupling of (13) with S-ethyl-2,3,4-tri-0-acetyl-l-thio-a-L-rhamnopyranoside affords the L-ribitol derivative (14) after further IM Ocessing. Also the 4-0-allyl derivative (IS) is a suitable precursor of glycoside (16). 

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. 

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 dimethylarsinoyl derivative of sulfated ribitol (see Fig. 2, compound 15) was isolated from the red alga Chondria crassicaulis (38). It had been observed as a major arsenical in C. crassicaulis by high performance liquid chroma-tography-inductively coupled plasma mass spectrometry (HPLC-ICPMS), and was initially reported as an unknown because it did not match any available standard (39). Subsequently, the compound was isolated and a chemical structure was proposed chiefly on nuclear magnetic resonance (NMR) data chemical synthesis of authentic material confirmed the proposed structure (38). This com-... 

The key-step in the synthesis of the 4-thio-oc,P-D-ery/Aro-pentofuranose derivative 31 from L-arabinose was the well-established ring-closure 29 ->30 (see Vol. 29, Chapter 11, Ref. 14). A range of other 2-deoxy-D-ery/Aro-pentose dibenzyl-dithioacetals have been prepared and similarly cyclized to 2-deoxy-4-thio-D-eryt/jro-pentofuranose derivatives. A synthesis of 4-thio-l,4-anhydro-L-ribitol (32) from D-arabinitoI was based on the episulfonium ion rearrangement shown in Scheme The conformation of 4-thio-L-lyxono-1,4-lactone is referred to in Chapter 21. 

A synthesis of l,4>dideoxy-l,4-iniino D-ribitol from the 3,4-ddiydroproIine derivative 60 has been reported. ... 

An improved synthesis of 1,4-dideoxy-l,4-imino-D-lyxitol derivatives, required for preparing swainsonine, starts from 3,4-0-benz-ylidene-D-ribono-1,5-lactone, going via the azido-ribitol (16) to the pyrrolidine (17). 

The synthesis of all positional isomers of partially methylated-acetylated or methylated-benzoylated derivatives of 1,4-anhydro-D-xylitol, 1,4-anhydro-L-fucitol, 1,4-anhydro-D-ribitol, 1,5-anhydro-D-mannitol, 1,5-anhydro-D-gJu-citol, and IjS-anhydro-D-galactitoP" have been described. The compounds should be useful as standards for determining the primary structure of polysaccharides after reductive cleavage. 

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