Erythrose 2,4-0-ethylidene

Treatment of the monoethylidene-D-mannitol with lead tetraacetate or periodate resulted in the consumption of two molecular equivalents of oxidant with the concomitant production of one mole of formaldehyde, one mole of formic acid and a monoethylidene-D-erythrose, the latter being identified by its conversion into the known crystalline D-erythrosazone.118 This evidence limited the choice of structure for the mannitol acetal to the 1,3- and 2,3-compound (4,6- and 4,5- are the respective identical structures). Two additional facts eliminated the latter alternative, first, the tetratosyl ester gave only one mole of sodium p-toluenesulfonate when heated with sodium iodide in acetone, and secondly, the same monoethylidene-D-mannitol was obtained from the above 1,3,4,6-diethylidene-D-mannitol by acidic hydrolysis.118 For these reasons Bourne, Bruce and Wiggins118 assigned to the mono-, di- and tri-ethylidene-D-mannitols, respectively, the 1,3-, 1,3 4,6- and 1,3 2,5 4,6- structures. 

An analogous approach to 3-deoxyglyculosonic acids would be realized were an ylide 149 (R= C02Et X= NR 2) available. Nevertheless, this problem was solved in an original way. The condensation of 2,4-O-ethylidene-D-erythrose with the sodium salt of ethyl (diethyl-... 

The introduction of the phosphonate grouping into a sugar molecule (see Section III, 3 p. 260) has been further investigated by Paulsen and coworkers.97 Thus, the phosphonate phosphorane 120a was shown to react with 2,3,4,5,6-penta-O-acetyl-a/dehydo-D-glucose, 2,3 4,5-di-0- isopropylidene - aldehydo - D - arabinose, and 2,4-0-ethylidene-a/dehi/do-D-erythrose, leading to the unsaturated phos-phonates 229, 230a, and 231, respectively, in moderate yields. 

Erythrose, 4-acetamido-4-deoxy-L-, 179 —, 2,4-O-ethylidene-D-, 24 —, 2,3-0-isopropylidene-/3-D-, 33 Ethylene oxide, oxo reaction with, 63 Eumycophyta, polysaccharides of, 367... 

B. (-)-2,4-O-Ethylidene-D-erythrose. A 1-L, three-necked, round-bottomed flask, equipped with a thermometer and two 200-mL pressure-equalizing dropping funnels, is charged with a suspension of sodium metaperiodate (59.2 g, 27> mmol, Note 11) in water (450 mL). The flask is cooled to 0°C using an ice-water bath. A solution of (-)-4,6-O-ethylidene-D-glucose (29.2 g, 142 mmol, Note 12) in water (120 mL) is added dropwise with stirring and under permanent control of the pH (Note 6) and... 

According to ref. 5, monomeric (-)-2,4-0-ethylidene-D-erythrose may be obtained by heating a solution of the dimer in ethyl acetate with a catalytic amount of glacial acetic acid or 100% phosphoric acid for 20 min at 90°C. 

Optically active C4-building blocks of type 1 are versatile starting compounds in organic synthesis. Important members of this class, among numerous others, are derivatives of threose8-9 and erythrose, respectively, such as 2,4-O-ethylidene-D erythrose 2, the corresponding "Horner enoate" 3, or the erythritol 4. 

As described here, 2 can be prepared in two steps from commercially available D-gluco e in up to 65% overall yield. Procedures to obtain the ethylidene glucose1012 and the ensuing oxidative degradation8-512-16 are based on earlier literature reports. The D-erythrose acetal 2 has also been prepared from D-mannitol in three steps, with an overall yield of 7%.17 The erythritol 4 can be synthesized from 2 by reduction with sodium borohydride 8 A mixture of Z/E-3 (ca. 2 1) is known to result from a Witting reaction of 2 with ethoxycarbonylmethylenetriphenylphosphorane 2a,6,7... 

In several experiments it was found that the yield of 2,4-O-ethylidene-D-erythrose generally is somewhat lower when the reaction is performed on a larger scale. 

O-benzylidene-D-erythrose.123 The 3-hydroxyl group in the former is well disposed for nucleophilic attack on the benzylic carbon atom, to give the cts-fused, 1,3-dioxolane ring. Similarly, Ballou124 found that 2,4-O-ethylidene-D-erythrose in methanolic hydrogen chloride affords methyl 2,3-0-ethylidene-/3-D-erythrofuranoside. 

The product from periodate-oxidation of 4,6-0-ethylidene-D-glucose after acetylation was shown to be the erythrose dimer (2). Acetylation of an... 

Aldol condensation of 2,3-0-ethylidene-D-erythrofuranose with formaldehyde gave the 2-C-hydroxymethyl-erythrose derivative (6), an isomer of apiose, which was characterized through aldonolactone and glycoside derivatives 2,3-O-isopropylidene-D-ribose similarly yielded D-hamamelose (2-C-hydroxymethyl-D-ribose) after deprotection. ... 

Knoevenagel-Doebner condensations of 2,4- -ethylidene-D-erythrose and -D-threose with malonlc acid or its mono-methyl ester furnishes... 

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