Hex-2-enono-1,4-lactone

L-fhreo-Hex-2-enono-1,4-lactone (L-Ascorbic acid is the equilibrium mixture of all three isomers)... 

C6H706--Na+H20 Sodium D-en/thro-hex-2-enono-1,4-lactone, monohydrate SIASCB 38 420... 

D-mannono 1,4-lactones (8b, 9a, and 10a) react readily with mesyl chloride in pyridine at 0 ° C to produce (197) the corresponding hex-2-enono-1,4-lactone 2-mesylates 150-152. 

Enantiomerically pure 4,5,6-trihydroxy-norleucins (for instance 325) were obtained (197) from the hex-2-enono-1,4-lactone-2-mesylates (such as 152). These butenolides were stereoselectively hydrogenated to afford, upon treatment with sodium azide, the C-2-inverted derivatives, such as 324. Reduction of the azide function and hydrolysis of the acetal group gave the amino acids (namely 325), which were converted into lactones in acid media. 

Selective phosphorylation of 5,6-O-isopropylidene D-erythorbic acid (D-erpt/zro-hex-2-enono- 1,4-lactone), the 5-epimer of L-ascorbic acid, was performed with phosphoryl chloride at high pH in the presence of pyridine. D-Erythorbate 2-phosphate (155) is obtained as the crystalline magnesium or cyclohexylammonium salts following removal of the 5,6-acetal.351... 

Starting from D-gulonic-y-lactone the salt was formed and a 0.5 M solution converted to D-Jcy/o-hex-2-ulosonate sodium salt monohydrate in the same manner as described for the preparation of sodium D-araZ>/ o-hex-2-ulosonate. Part of it was converted to methyl-D-xy/o-hex-2-ulosonate, and this further to D-/Areo-hex-2-enono-1,4-lactone (D-ascorbic acid) as described (72). The H and C-NMR spectra in H20 are identical to those of an authentic sample of L-ascorbic acid. 

C8H11NO5 2-Acetamido-2,3-dideoxy-D-erpfhro-hex-2-enono-1,4-lactone ADEHXLIO 38 437... 

Amino-2,3-dideoxy-e/7Z/iro -hex-2-enono-1,4-lactone, A-386 2-Amino-2,3-dideoxy-eryZ/iro -hex-2-enono-1,5-lactone, A-387 2-Amino-2,3-dideoxy-zAreo -hex-2-enono-l, 4-lactone, A-388 2-Amino-2,3-dideoxy-zAreo -hex-2-enono-l, 5-lactone, A-389 2-Amino-2,3-dideoxy-zAreo -hexopyranos-4-ulose, A-390... 

O -Methyl-D-arofeino -hept-2-enono-1,4-lactone, G-248 3- O -M-tiYi X-D-erythro -hex-2-enono-1,4-lactone, 1-49 Neuraminic acid iV-Benzoyl, N-35 Neuraminic acid iV-Benzyloxycarbonyl, N-35 Neuraminic acid iV-Ethoxycarbonyl, N-35 Neuraminic acid, N-35... 

C H NO , 2-Acetamido-2,3,-dideoxy-5,6-0-isopropylidene-D-threo-hex-2-enono-1,4-lactone, 44B, 399 C11H15N3O7, Tri-O-acetyl-a-D-arabinopyranosyl azide, 40B, 391 C11H15N3O7, Tri-0-acetyl-/3-D-xylopyranosyl azide, 42B, 320 Cl1H1gOa f 1-Deoxy-2-C-phenyl-D-arabinitol, 44B, 400 Cl1H1gOg, Methyl 4,6-di-0 acetyl-2,3-dideoxy-a-D-threo-hex-2-eno-pyranoside, 45B, 466... 

The yield of 2-0-benzyl-3-deoxy-L-/Areo-hex-2-enono-1,4-lactone obtained when 5-0-benzyl-l, 2-0-isopropylidene-a-D-glucofuranurono-6,3-lactone reacted with sodium borohydride (Scheme 105) has been improved by variation of the dipolar aprotic solvent and temperature. Five-membered 2-acetamido-2,3-dideoxy-D-hex-2-enonolactones have been synthesized from 2-acetamido-2-deoxy-D-aldono-1,4-lactones by treatment with dicyclohexylamine in ethanolic... 

Inhibition by four isomeric 2-acetamido-2,3-dideoxy-D-hex-2-enonolactones viz. 2-acetamido-2,3-dideoxy-D-eryr o- and -D-/Areo-hex-2-enono-l,4-lactones and the corresponding 1,5-lactones) of the j8-D-2-acetamido-2-deoxyglucosidase from bovine epididymus has been examined. The o-ery/Aro-lactones were shown to be weak competitive inhibitors, whereas the D-//jreo-lactones were inactive. The activity of 2-acetamido-2,3-dideoxy-D-eryr ro-hex-2-enono-1,4-lactone against this enzyme from a number of animal and plant sources was also tested, although 2-acetamido-l,5-anhydro-2-deoxy-D-ara6mu- and -L.-lyxo-hex-l-enitol were much more effective inhibitors. 

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