Of D-apiose

III. Occurrence of Apiose in Nature The chemistry of D-apiose (1) and apiin (4), from which this... 

A free disaccharide containing apiose has been extracted from an Australian shrub, the native hop bush, Daviesia latifolia.40 The disaccharide was isolated as a dibenzoate. Methylation followed by de-benzoylation, as well as comparison with the disaccharide of D-apiose from apiin, suggested that they are similar in every aspect measured. Thus, the structure of the disaccharide without its two benzoyl groups is, tentatively, 2-O-D-apiofuranosyl-D-gIucose.40 The... 

The first report, by Bell and coworkers61, identifying D-apiose as a component of a molecule other than a flavonoid glycoside was important for three reasons. (I) It was the first time that D-apiose had been described as a component of a polysaccharide, (2) the useful and widely emulated preparation of the di-O-isopropylidene derivative was detailed, and (3) a theory equating the recalcitrance of Posidonia australis and Zostera marina to microbial decay with the presence of some derivative of D-apiose was proposed. Subsequently, the presence of apiose in the polysaccharides of a large number of plants has been reported. 

L. gifofoa,65-79-83 and P. crispum.m,7 , H2 H4,H5 In general, the results of these in vivo investigations, as well as those of in vitro biosynthetic studies, support the hypothesis proposed for the synthesis of D-apiose polysaccharides and apiin (4) by Grisebach and Dobereiner82 (see Fig. 1). They postulated that decarboxylation of a nucleoside... 

FIG. l.-Transglycosylation of D-Apiose from UDP-D-apiose (5). (Studies in vitro showed that UDP-D-apiose uridine 5 -[3-C-(hydroxymethyl)-a-D-erythrofiiranosyl pyrophosphate] functions in a transglycosylation reaction. The product is apiin, 4, 5-dihydroxyflavon-7-yl 2-0-[3-C-(hydroxymethyl)-/3-D-erythrofuranosyl]-/8-D-glucopyran-oside (4), formed through the aid of an acceptor molecule.7 Additional products that may be formed by transglycosylation from an apiose donor-molecule include, principally, apiose-containing polysaccharides.)... 

The enzyme catalyzing the transfer of D-apiose from UDP-apiose to 4, 5-dihydroxyflavon-7-yl /3-D-glucopyranoside is commonly called apiin synthetase.7 Activity is measured by the formation of [14C]apiin from UDP-[U-14C]apiose. Apiin synthetase can be measured by the rapid separation and isolation, by poly(ethylenimine)-paper chromatography, of a product of the reaction, namely, [14C] apiin, from UDP-D-[U-14C]xylose and degradation products of UDP-[U-14C]apiose.31 There are reports of the isolation and purification of apiin synthetase from parsley leaves,31 from cell-suspension cultures of parsley,121 and from foxglove (Digitalis purpurea).31 Apiin synthetase isolated from parsley does not require metal ions, NAD+, or other cofactors, and is soluble. It is inhibited by several heavy metals, but not by tetra-N-... 

Chemical synthesis of D-apiose has been accomplished by a number of methods.18,20,63 A one-step conversion of the branched-chain pentose 4-C-(hydroxymethyl)-D-threo-pentose (9) yielded18... 

Synthesis of D-apiose from 1,2-O-isopropylidene- -L-threofuranose (28) has been accomplished.128 Oxidation with ruthenium tetraoxide... 

The di-O-isopropylidene derivatives of D-apiose are prepared by treating the sugar with acetone containing 5% (v/v) of concentrated sulfuric acid.61-63,130 The structures of these derivatives were first... 

The value of some nucleosides for use as flavor enhancers,1348 and the possible antiviral or antitumor activity of certain nucleosides,135 have led to the synthesis of purine nucleosides containing analogs of D-apiose in which the ring-oxygen atom of the furanose forms has been replaced.136 Monomolar p-toluenesulfonylation of 3-C-(hydroxy-methyl)-l,2-0-isopropylidene-/3-L-threofuranose (50) yielded 3-C-(hydroxymethyl)-l,2-0-isopropylidene-31-0-p-tolylsulfonyl-/3-L-thre-ofuranose (51) which, through a series of steps, was converted into either methyl 2,3-O-isopropylidene- [3-C-(hydroxymethyl)-4-thio-/3-D-... 

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