Masanori Yamaura

New Aldobiuronic Acid, 3-O-α-D-Glucopyranuronosyl-L-rhamnopyranose, from an Acidic Polysaccharide of Chlorella vulgaris.

The new aldobiuronic acid, 3-O-α-D-glucopyranuronosyl-L-rhamnopyranose, was isolated from the acid hydrolyzate of an acidic polysaccharide in cells of Chlorella vulgaris K-22. Its structure was elucidated by NMR spectroscopic analyses.

Total synthesis of antibiotic karnamicin B1

Abstract The novel antifungal karnamicin B 1 ( 1 ), 5-hydroxy-3,4-dimethoxy-2-{2-(4-oxopentyl)-4-thiazolyl}pyridine-6-carboxamide was first synthesized via the formation of partially methylated trihydroxy pyridine by ring-transformation from the corresponding furan derivative and subsequent regioselective introduction of 2,6-substituents using Meisenheimer-type reaction.

Regioselectivity in the reductive ring-opening reaction of 1,2-O-benzylidene sugars

Abstract Regioselectivity in the ring-opening reaction of 1,2- O -benzylidene sugars was studied. In the reductive ring-opening reaction of 1,2- O -benzylidene derivatives, only a C O 1 bond was cleaved in the case of manno -type, but both the C O 1 and C O 2 bonds were cleaved in the case of gluco -type.

Synthesis of 3‐O‐β‐D‐Glucopyranosyl‐(3R)‐hydroxybutanolide (Kinsenoside) and 3‐O‐β‐D‐Glucopyranosyl‐(3S)‐hydroxybutanolide (Goodyeroside A)

The first synthesis of 3‐O‐β‐D‐glucopyranosyl‐(3R)‐hydroxybutanolide (Kinsenoside) and 3‐O‐β‐D‐glucopyranosyl‐(3S)‐hydroxybutanolide (Goodyeroside A) is described. The diastereomers of the aglycon in 2‐O‐β‐D‐gulucopyranosyl‐1,2,4‐butanetriol derivatives, which were separable precursors of Kinsenoside and Goodyeroside A, were synthesized from optically nonactive 1,2,4‐butanetriol and α‐D‐glucopyranosyl trichloroacetimidate in excellent yields.

Practical Synthesis of 1,2‐O‐Benzylidene and 1,2‐O‐p‐Methoxybenzylidene Hexopyranoses

An improved and practical synthesis of 1,2‐O‐benzylidene and 1,2‐O‐p‐methoxybenzylidene hexopyranoses as useful synthons in carbohydrate chemistry is described. The reaction of 2‐benzoyloxyglycosyl bromide with sodium borohydride using excess amount of potassium iodide proceeded smoothly to give the corresponding 1,2‐O‐benzylidene derivative in good yields.

Reductive Ring‐Opening Reaction of 1,2‐O‐Benzylidene and 1,2‐O‐p‐Methoxybenzylidene‐α‐D‐glucopyranose Using Diisobutyl Aluminum Hydride

Abstract Regioselectivity in the reductive ring‐opening reaction of 3,4,6‐tri‐O‐benzyl‐1,2‐O‐benzylidene and 3,4,6‐tri‐O‐benzyl‐1,2‐O‐p‐methoxybenzylidene‐α‐D‐glucopyranose using diisobutyl aluminum hydride (DIBAH) was examined. The ratio of the 1‐O‐ and 2‐O‐p‐methoxybenzyl ethers, which were generated from endo‐type 1,2‐O‐p‐methoxybenzylidene, was variable by the change of solvent.