Aldonic acids deoxy-, lactone

The bromodeoxyaldonolactones have been used for the preparation of aminodeoxy aldonic acids and aminodeoxy sugars via azido derivatives (45,46). Likewise, a- and /J-aminopolyhydroxy acids have been prepared by treatment of the bromodeoxyaldonolactones with liquid ammonia (47). Thus, 3-amino-3-deoxy-D-threonic acid and 3-amino-3-deoxy-D-arabin-onic acid (40b) were obtained from 2-bromo-2-deoxy-L-threono- or D-xy-lono-1,4-lactone (38). It was shown that 2,3-epoxy carboxamides (namely, 39) are intermediates of the reaction. Heating at 90° for long periods led to the 3-amino-3-deoxyaldonamides, which upon acid hydrolysis yielded the corresponding aldonic acids. 

There are three known metabolic pathways to 3-deoxyulosonic acids. In the first, aldonic acids, formed by oxidation of aldopyranoses to the corresponding lactones, are dehydrated to the ulosonic acids (see Fig. 6). Thus, D-arabinose is converted by way of D-arabinonic acid to 3-deoxy-o-ffZj/cero-pentulosonic acid. The latter is then subjected to oxidative cleavage, yielding pyruvic and glycolic acids. L-Arabinose is oxidized and dehydrated to the 3-deoxy-L-g Z2/cero-pentulosonic acid, which is further oxidized to... 

On oxidation (with hypoiodite) to the corresponding aldonic acid, of the disaccharide obtained by partial hydrolysis of chitin, and acetylation with sodium acetate in acetic anhydride, the product undergoes /3-elimination, to give the bionic acid derivative 2-acetamido-4-0-(2-acetamido-tri-0-acetyl-2-deoxy- -D-glucopyranosyl)-6-0-acetyl-2,3-dideoxy-D-erj/(firo-hex-2-enono-1,5-lactone (90). In the original work, the determination of the site... 

Aldol condensation of 2,2-diethyl-l,3-dioxolan-4-one lithium or zirconium enolates with aldehydo sugars has afforded higher carbon aldonic acid derivatives, e.g. 1. The synthesis of L-ribono-1,4-lactone has been achieved from d-isoascorbic acid by way of the tetrose and pentitol derivatives 2 and 3 and the d-ribonolactone derivative 4 has been efficiently epimerized to the L-lyxonolactone 5 (Scheme 1). A selective i yn-epoxidation of racemic 2-0-benzyl-4-alkenamides followed by hydrolysis has afforded 3-deoxy-pentono-1,4-lactones. 

Benzoylation of L-rhamnono-5-lactone can, under mild conditions, give the triester, but more forcing reaction conditions can be used to produce either the 3-deoxy-2-ene (8) or the pyranone derivative (9) in good yields. The unsaturated aldonic acid derivatives (10) and (11) were produced each in about 20% yield on heating of the selenoxide (12) the main product was formed by direct elimination between C-2 and C-3. ... 

Cyclocondensation of l-alkylamino-l-deoxy-D-/Arco-pentuloses with ethyl acetoacetate led to iV-alkyl-pyrrole derivatives (24). Aldonic acid lactones react with ethyl isocyanoacetate in presence of DBN to yield oxazole derivatives, e.g. 2,3 5,6-di-0-isopropylidene-D-mannono-l,4-lactone yields the oxazole (25), whereas with potassium hydride as base octenonate derivatives... 

The isomeric 2-deoxy-1,4-lactones 8 and 9 have been synthesized in a multi-step procedure from levoglucosenone, while the branched lactones 10 and 11 have been prepared by radical addition [C6H13I or Ph(CH2)3l, Bu3SnH, AIBN] to an unsaturated aldonic acid ester.The lactone 12, an intermediate in the synthesis of pseurotin A, has been prepared from D-glyceraldehyde in a multi-step procedure. Thermally-induced cleavage of nitrate ester 13 [derived from... 

The enantiomerically pure 2,3-unsaturated aldonic lactone 2 was prepared following Sharpless asymmetric dihydroxylation of 2-vinylfuran to give 1 (Scheme 1). The chain-extended aldonolactones 4 and 5 were prepared from the P-keto ester 3 by use of a diastereoselective reduction with either d- or L-tartaric acid in conjuction with sodium borohydride (Scheme 2). Reaction of Meldrum s acid (5a) with D-aldopentoses and hexoses gave 3,6-anhydro-2-deoxy-aldono-... 

Treatment of peracylated sugar lactones as shown in Scheme 3 gives terminally-iodinated methyl aldonates. The suggested sequence of events is indicated 1,4-lactones behaved similarly, as did O-pivaloyl or (7-benzoyl derivatives, and woik-up with ethanol gave ethyl esters.l Methyl 4-bromo-4-deoxy-L-threonate (22) has been prepared by oxidative degradation of L-ascorbic acid, and introduction of bromine using TPP-carbon tetrabromide.l ... 

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