D-Threonic acid

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. 

Five pentosaccharinic acids were formed when D-xylose was treated with calcium hydroxide. This mixture included 2-C-methyl-D-threonic acid and 2-C-methyl-D-erythronic acid, the structures of which were... 

L-erythronic acids, respectively, and D-xylose to D-threonic acid.44 Isbell et al. elucidated the mechanism of this process45 (see the following Chapter). Degradation to a lower aldonic acid can be achieved by oxidation of an unsaturated sugar derivative. The method of Reichstein et al.46 for the preparation of L-threono-1,4-lactone by permanganate oxidation of 5,6-0-isopropylidene-L-ascorbic acid was improved by Perel and Dayton to afford the crystalline lactone in 65% yield.47... 

Ishizu et al.29H found that D-xylose and D-fructose react with aqueous calcium hydroxide to produce 13 lactonizable saccharinic and other acids. These were identified after separation by cellulose column and gas-liquid chromatography, and the Cs-saccharinic acids, 2-C-methyl-D-threonic acid (117) and 2-C-methyl-D-erythronic acid (118), were among those isolated. These authors299 later reported that L-sorbose reacts similarly, to generate 14 lactones, including the 2-C-methyl-L-xr/o o-l,4-lactone and 2-C-methyl-L-lyxono-1,4-lactone, which were also prepared from 1-deoxy-L-threo-pentulose via the cyanohydrin reaction. 

Deoxy-D-threonic acid, D-688 3 -Deoxythymidine, D-380 3 -Deoxy-5"-thymidylic acid, D-380... 

Thioxylose, T-99 Thomosamine, A-377 THP-ADM, A-58 THP-ADR, A-58 L-Threaric acid, T-12 D-Threaric acid, T-12 L-Threitan, T-24 DL-Threitan, T-24 Threitol, T-lOO Threoflavin, T-101 L-Threonamide, T-161 L-Threonic acid, T-161 D-Threonic acid, T-161 DL-Threonic acid, T-161 L-Threono-1,4-lactone, T-161 D-Threono-1,4-lactone, T-161 DL-Threonolactone, T-161 A -(A -Threonylcarbonyl)adenosine, R-114 Threopentulose, P-48... 

Prokaryotic organisms synthesise a primary form of vitamin pyridoxol 5 -phosphate from 1-deoxy-D-xylulose 5-phosphate (l-deoxy-D-t/treo-pent-2-ulose 5-phosphate) and 2-amino-2-deoxy-D-threo-tetronic (2-amino-2-deoxy-D-threonic) acid, known as 4-(phosphohydroxy)-L-threonine or 4-hydroxy-i-threonine 4-phosphate. Phosphohydroxythreonine arises from D-erythrose 4-phosphate, a product of decomposition of D-fructose 6-phosphate. Non-phosphorylated forms (pyridoxal, pyridoxol and pyridoxamine) are produced by hydrolysis of the corresponding phosphates. Animals do not synthesise vitamin Bg de novo, only convert the non-phosphorylated forms in the Hver, erythrocytes, and other tissues into the corresponding phosphates and the individual forms of each other. Pyridoxal 5 -phosphate arises by oxidation of pyridoxol 5Lphosphate and transamination of pyridoxal 5 -phosphate provides pyridoxamine 5Lphosphate. Both these forms of vitamin Bg are catalytically active. Pyridoxal 5 -phosphate... 

The principle of the reactions between aldonolactones and HBr-HOAc is illustrated in Scheme 1 (entries I and II), and the mono- and di-bromodeoxylactones prepared in this way are listed in Table 1. The 2-bromo-2-deoxy-D-erythrono-and D-threonolactone can be prepared analogously to the L-isomers [11] from the salts of D-threonic and o-erythronic acid [ 12], respectively. The former can be prepared by oxidative degradation of D-xylose following an analogous procedure described by Humphlett [13]. 

Two papers have thrown light on the finer structure of Appel s diacetal. First, Gatzi and Reichstein141 oxidized it with potassium permanganate in alkaline solution and obtained a diethylidene-L-xylonic acid, together with a monoethylidene-L-threonic acid. The ethylidene group in the latter compound was shown to span positions 2 and 4, from which they concluded that the parent diacetal was 1,3 -diethylidene-D-sorbitol (XXXI). Secondly, Bourne and Wiggins117 hydrolyzed the... 

Deoxy-D-erythronic acid 4-Deoxy-L-erythronic acid 4-Deoxy-o-threonic acid 4-Deoxy-L-threonic acid... 

Tetrulose, h-glycero-, phenylosazone, 148 Thioaldonic acids, phenylhydrazides, 165 Thiogalaotonic acid, d-, phenylhydra-zide, 118-120, 122 Threaric acid, dl-, 178 Threonic acid, dl-, 179 —, 4-chloro-4-deoxy-DL-, 179 —, (-)-4-deoxy-, 180 —, 4-deoxy-D-, 171, 181 —, 4-deoxy-DL-, 180 —, 4-deoxy-L-, 171 Tragacanthin, 272, 279 Transformations, of carbohydrates, 65 Trehalose, 323... 

Isopropylidene-D-erythrose has been obtained from 0-arabinose by a route which does not involve the intermediacy of the lactone.All of these processes suffer from either relatively low overall yields or the requirement of a large number of individual stages. The procedure described here, which is based on a similar oxidative degradation of L-ascorbic acid (vitamin C) to L-threonic acid, is undoubtedly the most expeditious route to the acetonide of Q-erythronolactone available. In addition, the starting material, erythorbic acid, is an inexpensive and readily available substance, commonly used as a food preservative. It is pertinent to note that recently L-ascorbic acid has itself found synthetic utility as a precursor to (R)-glycerol acetonide, an Important C3 chiral synthon, ... 

The oxidation of ascorbic acid still attracts attention and a mechanism has been proposed for the reaction with photochemically produced H02 radicals. An analogous reaction with hydrogen peroxide affords a means of access to L-threonic acid. Heating D-isoascorbic acid in aqueous pyridine in the presence of boric acid gives the decarboxylation products D-arabinose and D-ribose. Two Russian papers have reported on the oxidation of ascorbic acid with copper(ll) in the presence and absence of oxygen and light. As part of a basic study of the action of oxidase and reductase enzymes, the reduction of Methylene Blue by ascorbic acid has been examined, in the presence of surfactants added to mimic the effects of the protein parts of the enzymes. ... 

Syntheses of some pentonohydroxamic acid derivatives are covered in Chapter 10. Alkaline degradation of 5-O-a-D-glucopyranosyl-D-fructopyranose (leucrose) has afforded two novel saccharinic acids, 2-C-(2-hydroxyethyl)eiy-thronic acid and 2-C-(2-hydroxyethyl)threonic acid. Treatment of 4,6-O-ethyl-idene-D-glucose with the sulfur ylid JNr,iST-diethyl trimethylsulfonium-acetamide gave the epoxyaldonamide 6 as well as stereoisomers. ... 

L-Ascorbic acid, an enediol, has been oxidized by sodium hypoiodite and by potassium permanganate to L-threonic acid (9). Such oxidation of double bonds does not occur in the enols alone, for D-arabinal is oxidized by H2O2 and OSO4 in er butanol to D-erythronic acid in addition to D-arabinose (10). Periodic acid and lead tetraacetate are useful for the cleavage of hexitols and glycosides to glyceraldehyde and glycolaldehyde (see Chapter... 

Various papers have appeared on the preparation of potentially-useful chiral synthons. Electrolysis of 2.3 5,6-di-Q-isopropylidene-D-mannitol at an oxide-coated nickel electrode gave derivatives (68, X=Me,K) of isopropylidene D-glyceric acid, and similar treatment of isopropylidene L-ascorbic acid gave the enantiomers. " Ester (69) could be prepared from L-ascorbic acid by deojqrgenation of an L-threonic acid derivative previously reported (Vol.l9, p.260), and reduced to the butanetriol derivative this now becomes... 

---