Erythrose preparation

Ruff noticed in the mother liquors of an erythrose preparation obtained by degradation of L-arabonic acid, a small amount of another sugar, apparently a keto tetrose, which was not oxidized by bromine. The ketose gave the same phenylosazone as that obtained from L-ery-throse, but was not isolated otherwise. Neuberg oxidized erythritol to form an optically inactive tetrose solution and claimed that color reactions showed the presence of a keto tetrose. 

The tetrosones have not been prepared. Fischer2 observed that erythrose phenylosazone is relatively resistant to concentrated hydrochloric acid on warming, some decomposition took place, but osone was not formed. 

Diels and Stephan173 treated the benzoate of 3-hydroxy-2-butanone with bromine, and obtained crystalline 1-bromo- and 1,1-dibromo- derivatives. With dilute alkali, these formed 4-deoxy-DL-gZycero-tetrulose and 4-deoxy-DL-erythrosone respectively. Both compounds gave with phenylhydrazine 4-deoxy-DL-erythrose phenylosazone, which had previously been prepared from the corresponding aldotetrose.174... 

D-afe-o-Heptulose (sedoheptulose) (XXXVII) has been synthesized from D-erythrose (XXXVIII) plus triose phosphate, using an aldolase preparation from peas.169 Aldolases from yeast and from rat liver also form heptu-lose phosphate from these substrates.7S(o) 170(a) Crystalline muscle aldolase causes the formation of L-jrZwco-heptulose (XXXVIIa) from a mixture of L-erythrose (XXXVTIIa) and hexose diphosphate.170(b)... 

In the experience of the present author, minor deviations from this procedure may result in decreased yields. Oxalacetic acid of high quality is essential, and this should be verified by a melting-point determination prior to use. Decarboxylation of oxalacetate has been reported111 to occur rapidly at pH 7, and it should be kept to a minimum by maintaining the pH as close to 10 as possible when dissolving the oxalacetic acid. A modification of the Comforth reaction is the co-balt(II)-ion-catalyzed condensation of D-erythrose 4-phosphate with oxalacetate to give 3-deoxyheptulosonic acid 7-phosphate112 (as a mixture of the arabino and ribo isomers). Other procedures for the preparation of KDO will be discussed in subsections 3 and 4 of this Section. 

We have extended our work on a new synthesis of the antiprotozoal antibiotic anisomycin to the necine bases of the pyrrolizidine alkaloids, in particular retronecine and crotanecine. The key intermediate, (2R,3S,4R)-2-(alkoxy-carbonylmethyl)-3,4—isopropylidenedioxypyrrolidine, has been prepared by three distinct routes from D-ribose and g-erythrose, using reactions of high stereoselectivity. 

D-Ardbinoae. Tetraacetyl-D-arabononitrile was prepared by Deu-lofeu and degraded to triacetyl-D-erythrose and D-erythrose diacetamide by ammonia-silver oxide. Hockett and Maynard improved the yield of the nitrile and by hydrolysis of D-erythrose diacetamide with 0.6 N sulfuric acid obtained D-erythrose as a sirup from which methyl D-ery-throside was prepared. 

Preparation of DL-erythrose succeeded,18 however, in a stepwise procedure. Lactone 12 was cleaved with alcoholic potassium hydroxide to potassium DL-erythronate (13a) which was next acetylated to 13b. The acid chloride 14, obtained from 13b, was then reduced under the conditions of the Rosenmund reaction to the desired DL-erythrose. 

Both of the stereoisomeric DL-tetroses were obtained21 from 1,1-diethoxy-2-butyn-4-ol (18a). In two steps, involving acetylation of 18a and partial hydrogenation of the triple bond in derivative 18b, cis-4-acetoxy-l,l-diethoxy-2-butene (19) was prepared. ci.s-Hydroxylation of 19 with potassium permanganate, followed by acetylation, led to 20. Hydrolysis (basic, and then acidic) of the protecting groups yielded DL-erythrose (28%). 

Good yields are obtained at all stages of this synthesis of 2-desoxy-D-ribose, and for preparative purposes Sowden167 claims that the isolation of intermediates is unnecessary. The method would be a valuable one for the preparation of 2-desoxy-D-ribose if D-erythrose were obtainable in a pure state in large quantities. Overend and coworkers1 8 have investigated various methods for the preparation in bulk of this tetrose from easily accessible materials, but a completely satisfactory method is still required. 

Pyocyanin (160) is derived from the shikimate pathway, and one protein, PhzC, is equivalent to enzymes that catalyze the first step in this pathway, converting erythrose 4-phosphate (162) and phosphoenolpyruvic acid (163) to 3-deoxy-D-arabinoheptulosonate 7-phosphate (164) (Fig. 28). The equivalent enzyme in the shikimate pathway is thought to be feedback regulated, and PhzC is likely to shunt intermediates toward the shikimate pathway in preparation for pyocyanin (160)... 

A second monobenzylidene-D-sorbitol (m. p. 132-133°) has been prepared by Sowden 68 it is the 4,6-acetal, which was produced by hydrogenation of the known 4,6-benzylidene-D-glucose, and which gave 2,4-benzylidene-D-erythrose when subjected to periodate oxidation. 

Starting from (S)-ethyl-P-hydroxybutanoate 53, different synthetic applications have been developed such as the preparation of synthetic equivalents of 2,4-deoxy-2-amino-L-threose 54 and L-erythrose 55 [25], and the obtaining of 4-ace-tylamino-2,4,6-trideoxy-L-ribo-hexose 56 [26], of Af-acetyl-L-tolyposamine 57 [27] and of ci s-monobactams 58 [28] (Scheme 27). 

Acetylated nitroolefins have been prepared in similar fashion from D-erythrose,80 D-arabinose, D-ribose and D-glucose. The ease with which the acetylated nitroolefins usually crystallize is exemplified by the experience with D-glucose. Here, the product, D- lwco-pentaacetoxy-1-nitroheptene-1, was obtained in the crystalline state from a sirupy mixture containing approximately twenty times the nitroolefin s weight of other acetylated carbohydrate material, formed from the original... 

Experimental Details.20 1—A solution of 2.2 g. of o-erj/yield from sirupy D-erythrose without the isolation of intermediates) in 50 cc. of absolute ethanol was shaken with hydrogen at room temperature and atmospheric pressure in the presence of 0.2 g. of freshly prepared palladium black. The hydrogenation was interrupted after twenty minutes when 1.05 mole-equivalents of hydrogen had been absorbed and the rate had become slow. The sirup obtained after filtration and concentration was stirred with a mixture of 40 cc. of 1 AT sodium hydroxide solution and 10 cc. of ethanol. After the sirup had dissolved, the solution was added dropwise to a stirred mixture of 5 cc. of sulfuric acid and 7.5 cc. of water at 0°. The reaction mixture was then diluted with ice-water and neutralized by stirring with solid barium carbonate. After filtration, a few drops of glacial acetic acid were added to the filtrate and it was concentrated at reduced pressure to a sirup. The sirup was taken up in a small volume of 75% ethanol and 1.5 cc. of a-benzyl-a-phenylhydrazine added. Slow evaporation of this solution then gave 1.4 g. (59%) of D-erytkro-2-desoxypentose benzylphenylhydrazone. 7 After recrystallization from aqueous ethanol, the pure hydrazone melted at 127-128° and showed [a] — 17.7° in pyridine, c 2. 

In extracts of a wild type of E. coli (Strain B), enolpyruvate phosphate and D-erythrose 4-phosphate are converted to a 3-deoxyheptulosonic acid (most probably of the arabino configuration) and two equivalents of orthophosphate. Since 3-deoxy-D-arai fno-heptulosonic acid 7-phosphate was readily dephosphorylated by these enzyme preparations, the conclusion was... 

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