Tetritols hydrolysis

Benzylidene-D-threitol (VII) was prepared by Haskins, Hann and Hudson79 by hydrogenation of 2,3-benzylidene-D-threose, a product of the periodate oxidation of 2,3-benzylidene-D-arabitol. The tetritol was proved to be D-threitol, rather than erythritol, by the fact that hydrolysis of VII and subsequent treatment with benzaldehyde afforded the known dibenzylidene-D-threitol. The acetal group was allocated to the 2,3-position on the basis of independent evidence concerning the structure of the parent benzylidene-D-arabitol (see page 152). For the physical constants of acetals of threitol see Table VIII. 

The large variety of core lipids reported previously to be present in M barkeri by De Rosa et al. [73], have not been confirmed by the studies of Sprott et al. [35] and Nishihara and Koga [36], who did not detect any C2o-C2o-tetritol diether, C20-C25 archaeol or caldarchaeol with 1-3 cyclopentane rings. The failure to detect hydroxyarchaeol core lipids [73,74] in M barkeri is probably due to the drastic hydrolysis conditions used [21,23]. 

Tetroses and Pentoses - 4-0- -Butyldimethylsilyl-2,3-0-isopropylidene-L-threose (1) has been prepared in seven efficient steps from o-xylose. 3,4-0-Isopropylidene-D-eythrulose (4) has been synthesized from the known tetritol derivative 2 by primary protection as the silyl ether 3, followed by Dess-Martin oxidation and desilylation. Compound 2 was derived from D-isoascorbic acid (see Vol. 22, p. 178, refs. 9,10). In a similar reaction sequence, the enantiomer 5 has been obtained from L-ascorbic acid. The dehomologation of several di-0-isopropylidenehexofuranoses e.g., 6- 7) has been carried out in two steps without intermediate purification, by successive treatment with periodic acid in ethyl acetate, followed by sodium borohydride in ethanol. Selective reduction of 3-deoxy-D-g/jcero-pentos-2-ulose (8) to 3-deoxy-D-g/> cero-pent-2-ose (9) has been achieved enzymically with aldose reductase and NADPH." 4-Isopropyl-2-oxazolin-5-one (10) is a masked formaldehyde equivalent that is easily converted to an anion and demasked by mild acid hydrolysis. One of the three examples of its use in the synthesis of monosaccharides is shown in Scheme 1. ... 

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