Aldonic acid

The branched-chain aldonic acid derivative (1) has been shown to be a component of avilamycin by isolation of the product (2) of mild methanolysis and acetylation the latter compound was structurally characterized by X-ray analysis.  

D-xylonate, respectively. Degradation of the chain also occurs to some degree when 2-deoxy-DTflraimo-hexose is treated with alkaline hydrogen peroxide, and D-arabinitol is produced together with 2-deoxy-DTflraZ mo-hexonic acid. A secondary process leads to the production of formic acid.  

D-mcn/io-heptonic acid, and its 6-epimer has been effected from the cyanohydrins of 1,2 3,4-di-O-isopropylidene-D- a/flcto-dialdose (see Chapter 8), and treatment of 5,6-anhydro-l,3 2,4-di-O-ethylidene-D-glucitol with the anion of ethyl acetoacetate led to the octonic acid -lactones (7). Ethyl cyanoacetate afforded related products that dimerized on hydrolysis.  

A continuous electrochemical procedure for the reduction of D-ribonO O -lactone which uses a membrane separation has been developed and applied on a pilot plant scale. 

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.  

So far only a table of the 13C chemical shifts of aldonic acid salts and aldonolactones has been published in the literature (Table 5.20, [696]). The carbons of the carboxylate ion groups of all D-aldonic acid salts resonate at 180 + 0.7 ppm. Upon /-lactone formation an upfield shift for C-l and a downfield shift for the /-carbon is observed throughout. 

Compound -ch3 -ch2 ch2oh 2-CHOH 3-CHOH 4-CHOH 5-CHOH och3 Ref. 

Work from Pedersen s laboratory on the treatment of pentonic acid salts with hydrogen bromide in acetic acid and reactions of the dl-bromo products is referred to in Chapter 7, and reference to 6-amlno-6-deoxyheptonlc acids is made in Chapter 8. 

Substituted aldonolactones react with epoxides in the presence of boron trifluoride to give spiro-products which can otherwise be made from diols under dehydrating conditions. By these two approaches both simple products and disaccharide products, e.g. (13) and (14), were made. Aldonolactone derivatives also react under Reformatsky conditions to give keto-acid derivatives which are dealt with in the ulosonic acid section below. 

spectroscopy it has been deduced that tri-O-acetyl-D-xylono-1,5-lactone exists in solution in a conformation close to the 4 half-chair. Brominated derivatives are referred to in the ascorbic acid section. 

The rate and efficiency of crystallization of calcium gluconate from solution following the electrode oxidation of glucose have been investigated, and this reaction at a platinum electrode is markedly catalysed by submonolayers of heavy metals (e.g, thallium, 

Interpreted in terms of reduced electrode poisoning. Treatment of 3-0 -raethyl-D-glucose with lead hydroxide in water gave the isomeric 2-deoxy-3-Q-methyl-D-arabino-hexonic acid in the presence of sodium hydroxide, however, the products were a- and 3-gluco-meta-saccharinlc acld.-  

Celloblose, maltose and - -methyl-D-glucose with anthraquinone 2-sulphonic acid in dilute sodium hydroxide solution degrade to give a series of substituted aldonic acids  

4- -substltuted-D-gluconic acid 4-0 -substltuted-D-raannonic acid 3- -substituted pentose acid (1) 

Mechanisms for the reactions were formulated based on these products and non-carbohydrate products, the main pathways being thought to involve 2-uloses and 2,3-diuloses. Compounds (1) are believed to be formed by benzlllc acid rearrangement reactions 

Specific rate constants for the hydrolysis of D-mannono-1,4-lactone have been determined, and the rate of acid-catalysed hydrolysis of the 4,6-dideoxy-L-hexono-1,5-lactones at 35°C in water, aqueous p-dioxan, and aqueous acetone was shown to decrease along the series xylo, lyxo, ribo, and arabino. The effects of the composition of mixed-solvent systems on the rate of hydrolysis were also investigated. 

The D-plycero-D-0u/o-heptono-l,5-lactone derivative (414) gave the heterocyclic heptopyranose derivative (415) on successive treatments with butyl- or phenyl-lithium and 2-bromopyridine. Heterocyclic derivatives related to (415) were also obtained when (414) reacted with 2-methylpyridine and benzothiazole, whereas it reacted with furan, thiophene, and 1-methylindole to give acyclic derivatives [e.g. (416)]. Chelation of the nitrogen atom of the heterocyclic ring with the intermediate alkoxide anion appears to deactivate C-1 towards further reaction with the former series of compounds. 

The principal volatile products formed on pyrolytic decomposition of D-xylan, xylotriose, xylobiose, and methyl /S-D-xylopyranoside were 3-hydroxy-2-penteno-1,5-lactone and 2-furaldehyde. These products appear to be formed in independent reactions, the lactone being derived from non-reducing D-xylopyranosyl residues. Oxidation of ethyl 4,6-di-0-acetyl-2,3-dideoxy-a-D-eryt/iro-hex-2-eno- 

HeleSic, K. Kefurt, and J. Jary, Coll. Czech. Chem. Comm., 1977, 42, 2193. 

Elemental analysis and i.r. spectroscopy have indicated that pangamic acid (vitamin Bjg) is 6-0-(dimethylglycyl)-D-gluconic acid.  

Silver carbonate on Celite in methanol causes the oxidation of 3,4,6-tri-, 3,4-di-, and 3-O-methyl-D-fructose to the corresponding ethers of D-arabinonic acid. The 1,4,6-, 1,4,5-, and 1-ethers cleave at C-2—C-3, whereas the 1,3,4,6-and 1,3,4-substituted compounds are resistant to reaction under these conditions. A suitable method for oxidizing 2,3 5,6-di-0-isopropylidene-a-D-mannofuranose and jS-D-allofuranose to the corresponding lactones involves 

A review (in German) of dichloromethyl methyl ether as a reagent in carbohydrate chemistry outlines its use in the conversion of sugar acids into the corresponding acid chlorides.  

L-Xylono-1,4-lactone can be obtained from the acid by storage over phosphorus pentoxide. The hydrolysis of the lactones of 4,6-dideoxy-L-xyto-, Lrlyxo-, L-ribo-, and L-araft/no-hexonic acids, and methyl ethers thereof, has 

Acetylation of 4,6-0-benzylidene-2-benzyloxycarbonylamino-2-deoxy-D-gluconic acid resulted in lactonization and jS-elimination to give compound (2), and similarly, D-glucono-1,5-lactone gave the corresponding unsaturated 

The syntheses of several dialkyl xylarates from xylaric acid, and their conversion to 2,4-0-isopropylidene acetals and thence 3-O-methacryloyl derivatives have been described. The copper(n) catalysed oxidation of tartaric acid by hexacyanoferrate in alkaline medium has been reported.  

The properties of aldonolactones in aqueous solution and as enzyme inhibitors have been reviewed.  

Heating of 2-deoxy-D-ara6/ o-hexonic acid resulted in appreciable lactoniza-tion on melting. Subsequent decomposition of the lactone involved dehydration, decarboxylation, and scission to yield water, carbon dioxide, carbon monoxide, 5-(2-hydroxyethylidene)-2(5/f)-furanone, acrylaldehyde, and acetic acid. 3-Deoxy-D-rj6( -hexono-l,4-lactone - which cannot undergo j3-elimination -is thermally more stable and gives products resulting from scission and dehydration. 

Treatment of o-fructose 6-phosphate with oxygen and alkali resulted in loss of C-1 and the formation of D-arabinonic acid 5-phosphate.  

The compounds discussed in the following section closely resemble some of the compounds mentioned in the section on C-glycosides in Chapter 3. The glycosyl cyanides (278) and (279) have been converted into the amino-acids (282) and (283) by way of the sulphonates (280) and (281), respectively/ The amino-acids (282) and (283) were used to prepare novel polymers which exhibited the properties both of polysaccharides and proteins. Investigations on the synthesis of puro-mycin analogues have led to the preparation of the 2,5-anhydro-D-allonic acid derivative (284) from 3-acetamido-3-deoxy-l,2-C -isopropylidene-a-D-ribofura- 

Litter and R. M. De Lederkremer, Anales Asoc. quim. argerttina, 1974, 62, 147 Chem. 

4-anhydroisosaccharinic acid (312) has been identified as one of the principal products formed by end-wise degradation of cellulose with alkali it is presumably formed by way of a benzylic acid-type rearrangement on the keto-fovm (314) of the pyran derivative (313). Characterization of (312) was accomplished 

Unsaturated derivatives of aldonic acids are mentioned in Chapters 13 and 14, while related amino derivatives are referred to in Chapter 8. 

Protected aldono-1,4- or -1,5-lactones [e.g. (316)] reacted with ethyl isocyano-acetate and base in an aprotic medium to give either a-(formylamino)acrylic ester derivatives [e.g. (317)] or, where base-catalysed elimination reactions can be suppressed, acyclic oxazole derivatives [e.g. (318)].  

A procedure for separating mixtures of D-ribono- and D-arabinono-1,4-lactones involved acid-catalysed benzylidenation and precipitation of the 2,3-0-benzylidene-D-ribono-1,4-lactone formed/  

Aldonic acids (e.g. melibionic and gentiobionic acids) derived from reducing disaccharides have been coupled to the amino-groups of proteins with the aid of a water-soluble carbodi-imide/ The immunochemical properties of some of the synthetic glycoproteins were assessed using plant agglutinins and antibodies raised towards the conjugates. 

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Derivatives of aldoses in which the terminal aldehyde function is oxidized to a car boxylic acid are called aldonic acids Aldonic acids are named by replacing the ose ending of the aldose by omc acid Oxidation of aldoses with bromine is the most com monly used method for the preparation of aldonic acids and involves the furanose or pyranose form of the carbohydrate... 

Aldonic acids exist m equilibrium with their five or six membered lactones They can be isolated as carboxylate salts of their open chain forms on treatment with base... 

Like aldonic acids aldaric acids exist mainly as lactones... 

When a preparative method for an aldonic acid is re quired bromine oxidation is used The aldonic acid is formed as its lactone More properly described as a reaction of the anomeric hy droxyl group than of a free aldehyde... 

Aldonic acid (Section 25 19) Carboxylic acid obtained by oxi dation of the aldehyde function of an aldose Aldose (Section 25 1) Carbohydrate that contains an aldehyde carbonyl group in its open chain form Alicyclic (Section 2 15) Term describing an a/iphatic cyclic structural unit... 

Other multifunctional hydroxycarboxylic acids are mevalonic and aldonic acids which can be prepared for specialized uses as aldol reaction products (mevalonic acid [150-97-0] (13)) and mild oxidation of aldoses (aldonic acids). 

PolysuWde Process. One modification to the kraft process being appHed commercially is the polysulfide process (38). Under alkaline conditions and relatively low temperature (100—120°C), polysulfides oxidize the active end group of the polysaccharide polymer to an alkaH-stable aldonic acid. This reaction, known for many years (39), was not produced on a commercial scale until the development of an efficient method for in situ generation of the polysulfide in kraft white Hquor. 

Oxidation to Sugar Acids and Lactones. When the aldehyde group of an aldose is oxidized, the resulting compound is an aldonic acid (salt form = aldonate) (11)4. Some aldonic acids are products of carbohydrate metaboHsm. 

The barium hydroxide serves to hydrolyze any unchanged nitriles as well as to precipitate the aldonic acid. 

Aldonic acid (Section 25.19) Carboxylic acid obtained by oxidation of the aldehyde function of an aldose. 

Note D-Gluconic acid and other aldonic acids exist in equilibrium with lactone structures. 

Although the Tollens reaction is a useful test for reducing sugars, it doesn t give good yields of aldonic acid products because the alkaline conditions cause decomposition of the carbohydrate. For preparative purposes, a buffered solution of aqueous Br2 is a better oxidant. The reaction is specific for aldoses ketoses are not oxidized by aqueous Br2. 

Much of the chemistry of monosaccharides is the familiar chemistry of alcohols and aldehydes/ketones. Thus, the hydroxyl groups of carbohydrates form esters and ethers. The carbonyl group of a monosaccharide can be reduced with NaBH4 to form an alditol, oxidized with aqueous Br2 to form an aldonic acid, oxidized with HNO3 to form an aldaric acid, oxidized enzymatically to form a uronic acid, or treated with an alcohol in the presence of acid to form a glycoside. Monosaccharides can also be chain-lengthened by the multistep Kiliani-Fischer synthesis and can be chain-shortened by the Wohl degradation. 

Aldonic acid (Section 25.6) The monocarboxylic acid resulting from mild oxidation of the -CHO group of an aldose. 

The 2-keto-3-deoxy-aldonic acid (phosphate) aldolases from Pseudomonas strains - 3-deoxy-2-keto-L-arabonate (F.C 4.1.2.18), 3-deoxy-2-keto-D-xylonate (EC 4.1.2.28), 3-deoxy-2-keto-6-phospho-D-gluconate (EC 4.1.2.14) and 3-deoxy-2-keto-6-phospho-D-galactonate aldolase (EC 4.1.2.21) - appear to be specific even for the acceptor components, but allow stereoselective syntheses of the respective natural substrates29. 

Monocarboxylic acids formally derived from aldoses by replacement of the aldehydic group by a carboxy group are termed aldonic acids (see 2-Carb-20). 

Oxo carboxylic acids formally derived from aldonic acids by replacement of a secondary CHOH group by a carbonyl group are called ketoaldonic acids (see 2-Carb-21). 

The parent that includes the functional group most preferred by general principles of organic nomenclature [13,14], If there is a choice, it is made on the basis of the greatest number of occurrences of the most preferred functional group. Thus aldaric acid > uronic acid/ketoaldonic acid/aldonic acid > dialdose > ketoal-dose/aldose > diketose > ketose. 

Aldonic acids are divided into aldotrionic acid, aldotetronic acids, aldopentonic acids, aldohexonic acids, etc., according to the number of carbon atoms in the chain. The names of individual compounds of this type are formed by replacing the ending -ose of the systematic or trivial name of the aldose by -onic acid . 

Esters derived from the acid function are also named using the ending -onate . The name of the alkyl (aryl, etc.) group is given before the aldonate name. Alternative periphrase names like aldonic acid alkyl (aryl, etc.) ester may be suitable for an index. 

Esters, lactones, lactams, acyl halides etc. are named by modifying the ending -ic acid as described for aldonic acids (2-Carb-20.2). 

Pyruvate-dependent lyases serve catabolic functions in vivo in the degradation of sialic acids and KDO (2-keto-3-deoxy-manno-octosonate), and in that of 2-keto-3-deoxy aldonic acid intermediates from hexose or pentose catabolism. 

A quantitative interpretation of aldonolactone inhibition in terms of an adaptation of the active site to a transition state approaching a planar, glycosyl oxocarbonium ion is made difficult for several reasons. Due to the interconversion between the 1,4- and 1,5-lactones, and their hydrolysis to the aldonic acids, their use is limited to kinetic studies with incubation times of 10 min or less. This was not realized by most investigators prior to 1970. In many cases, only the 1,4-lactone can be isolated its (partial) conversion into... 

Attack of the OH radical on carbohydrates of low molecular mass gives rise to a variety of products. Indeed, the reaction of radiolytically-generated OH radical with lower hexose sugars produces lower saccharides (for di- and higher saccharide species), uronic and aldonic acids, and 3-, 2- and 1-carbon aldehydic fragments, e.g. 

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