R. D. Guthrie

Allylic substitutions in tri-O-acetyl-glycals and related compounds

Abstract The reaction of tri-O-acetyl- d -allal or - d -glucal, ethyl 4,6-di-O-acetyl-2,3-dideoxy-α- d )-erythro-hex-2-enopyranoside, or 1,4,6-tri-O-acetyl-α,β- d -erythro-hex-2-enopyranose with sodium azide in acetonitrile under catalysis by boron trifluoride diethyl etherate yields a mixture of 4,6-di-O-acetyl-3-azido-3-deoxy- d -allal and - d -glucal, together with both anomers of 4,6-di-O-acetyl-2,3-dideoxy- d -erythro-hex-2-enopyranosyl azide. The mechanism of these reactions is discussed. 3-Amino-3-deoxy- d -allal and - d -glucal and their derivatives are described.

Derivatives of sucrose 3′,4′-epoxide

Abstract A facile, one-pot synthesis of α- d -glucopyranosyl 3,4-anhydro-β- d -tagatofuranoside (1) from sucrose in good yield is reported. Derivatives of 1 can also be obtained from 4,6:2,1′-di-O-isopropylidenesucrose and from 2,3,6,1′,6′-penta-O-benzoylsucrose by treatment with triphenylphosphine and diethyl azodicarboxylate. The n.m.r. spectra (13C,1H) and conformation of derivatives of 1 are discussed. A new anhydrosucrose (1′,4′) is reported.

Allylic substitutions in tri-o-benzyl-glycals,4,6-o-benzylidene-glycals and related compounds☆

Abstract 3,4,6-Tri-O-benzyl- d -glucal and the benzyl 4,6-di-O-benzyl-2,3-dideoxy-hex-2-enopyranosides react with sodium azide in acetonitrile under boron trifluoride catalysis to yield mixtures of 3-azido-glycals and 2,3-unsaturated glycosyl azides. Similar reactions with derivatives of 4,6-O-benzylidene- d -allal and -glucal and with related 2,3-unsaturated analogues gave only azido-glycals. The mechanism of these reactions is discussed and compared with reactions of the tri-O-acetyl-glycals and related systems.

Reaction of 4,6-O-benzylideneglycals with benzoic acid, triphenyl-phosphine, and diethyl azodicarboxylate and of the products with sodium methoxide. X-Ray structure of 1-O-benzoyl-4,6-O-benzylidene-2-deoxy-3-O-methyl-α-D-arabino-hexopyranose, C21H22O6

Reaction of 4,6-O-benzylidene-D-allal with benzoic acid, triphenylphosphine, and diethyl azodicarboxylate gave a mixture of 1-O-benzoyl-4,6-O-benzylidene-2,3-dideoxy-α-D-erythro-hex-2-enopyranose (3) as the major product together with its β-anomer (4) and 3-O-benzoyl-4,6-O-benzylidene-D-glucal (5). Debenzoylation led to a mixture of the 4,6-O-benzylidene-D-glucal, 4,6-O-benzylidene-2-deoxy-3-O-methyl-D-arabino- and -D-ribo-hexopyranose. The structure of the arabino-isomer (6) was established by X-ray analysis of its 1-O-benzoyl derivative. Crystals are orthorhombic, space group P212121, a= 21.789(2), b= 14.772(3), c= 5.925(2)A. The structure was solved by direct methods and refined to R 0.095.

d-fructose derivatives modified at C-4 by direct displacementand by oxirane opening

Abstract The epoxide ring of methyl 3,4-anhydro- β - d -tagatofuranoside is opened byattack of nucleophiles at C-4 to yield derivatives of D-fructose. Treatment of 2,3- O -isopropylidene-1,6-di- Op -tolylsulfonyl- β - d -fructofuranose with sulfuryl chloride resulted in attack at C-6, not C-4. 2,3- O -Isopropylidene-1,6-di- O - p -tolylsulfonyl- β - d -tagatofuranose behaved normally with this reagent. Methyl 4-deoxy- β - d - threo -hexulofuranoside was not hydrolysed by invertase.

Epoxidations with triphenylphosphine and diethyl azodicarboxylate. Part 1. Synthesis of methyl 3,4-anhydro-D-tagatofuranosides

Treatment of methyl β-D-fructofuranoside (6) with triphenylphosphine and diethyl azodicarboxylate in dimethylformamide gives a high yield of methyl 3,4-anhydro-β-D-tagatofuranoside (5); no blocking of the hydroxy-groups at C-1 and C-6 is necessary. The structure of the product was confirmed by an X-ray structural study of its 1,6-bis-O-(p-tolylsulphonyl) derivative and by an unambiguous synthesis. A similar reaction of methyl α-D-fructofuranoside yielded the 3,4-anhydro-α-D-tagatofuranoside. The reaction mechanism is discussed.

Epoxidation using triphenylphosphine–diethyl azodicarboxylate: synthesis of methyl 3,4-anhydro-α- and -β-D-tagatofuranosides

Facile syntheses of the title compounds have been achieved by the one-step reaction of methyl α- or β-D-fructofuranoside with triphenylphosphine and diethyl azodicarboxylate in dimethylformamide; no blocking groups were necessary.

Isolation of invertase from banana fruit (Musa cavendishii)

Abstract A soluble form of invertase (β- d -fructofuranoside fructohydrolase, EC 3.2.1.26) has been purified from ripe banana fruit ( Musa cavendishii ). The enzyme has a high specific activity and an apparent MW of 220 000 daltons; it appears to be glycoprotein containing 12.5% mannose and 12% glucosamine.