Showing papers by "Seiichiro Ogawa published in 1990"
TL;DR: This chapter focuses on the chemistry of carbahexopyranoses and their derivatives, which are carbocyclic analogs of true disaccharides in which one or both of the hexose or pentose residues is(are) replaced with a carbasugar.
Abstract: Publisher Summary This chapter focuses on the chemistry of carbahexopyranoses and their derivatives. The first three carbasugars were synthesized by McCasland and coworkers. Two other carbasugars were prepared from myo -inositol and the remaining eleven carbasugars have been synthesized from the Diels–Alder adduct of furan and acrylic acid. Fifteen enantiomers have been synthesized among the thirty-two carbasugars theoretically predicted. D -Fructose is the sweetest sugar known in naturally occurring carbohydrates and its intense sweetness is produced only by β- D -fructopyranose. Carbaglycosylamines [2,3,4-trihydroxy-5-(hydroxymethyl)-1-cyclohexylamine] and related compounds are well known to exist as the components of antibiotic validamycin complex and carbaoligosaccharidic alpha amylase inhibitor. Carbadisaccharides are carbocyclic analogs of true disaccharides in which one or both of the hexose or pentose residues is(are) replaced with a carbasugar. Besides sweetness, a carbasugar may have biological activity owing to its structurally close resemblance to a true sugar. The chemistry of carba-sugars is a newly opened area ofchemistry and the biological effects of these compounds have not been well studied, except for (1) the equisweetness of D-carba-glucose, D-carba-galactose, and D-carba- fructose with the respective true sugars, (2) the antibiotic activity of α-D- carba-galactose, and (3) the inhibition of a D-glucose-stimulated insulin release by D-carba-glucose.
143 citations
TL;DR: The E and Z isomers of (2R,4S,5R)-5-hydroxy-4-(3-hydrox-1-propenyl)-2-methyl-1,3-dioxane (3Z and 3E) were derived from 4,6-O-ethylidene-D-glucose (1), and their 5-Otert-butyldimethylsilyl derivatives (5Z and (5E) served as substrates for Claisen rearrangements with triethyl orthoacetate RE
Abstract: The E and Z isomers of (2R,4S,5R)-5-hydroxy-4-(3-hydroxy-1-propenyl)-2-methyl-1,3-dioxane (3Z and 3E), which were derived from 4,6-O-ethylidene-D-glucose (1), and their 5-O-tert-butyldimethylsilyl derivatives (5Z) and (5E) served as substrates for Claisen rearrangements with triethyl orthoacetate
24 citations
TL;DR: In this paper, the inhibitory activity against three hydrolases: α- and β-d -glucosidases, and α- d -mannosidase was evaluated.
21 citations
TL;DR: A total synthesis of (+)-aste1toxin, a novel mycotoxin isolated from Aspergillus stellatus, has been achieved by using D-glucose as an enantiomerically pure starting material as mentioned in this paper.
20 citations
TL;DR: Methyl oligobiosaminide, the core structure of oligostatin C, and five analogues, were synthesized by coupling the protected pseudo-sugar epoxide 46 with suitable methyl 4-amino-4-deoxy-alpha-D-hexopyranoside derivatives.
18 citations
TL;DR: In this article, the rifled antibiotic rifled antibiotics were synthesized from tetrahydrofuran, which was obtained from D-glucose as an enantiomerically pure starting material.
16 citations
TL;DR: Methoxyhygromycin, an antibiotic having a unique structure among the aminocyclitol antibiotics, and its 5-epimer are first synthesized and revealed that neo-configuration of cyclitol moiety is important for the appearance of antibacterial activity.
Abstract: Methoxyhygromycin, an antibiotic having a unique structure among the aminocyclitol antibiotics, and its 5-epimer are first synthesized. This synthesis fully confirmed the proposed structure of the antibiotic and revealed that neo-configuration of cyclitol moiety is important for the appearance of antibacterial activity.
14 citations
TL;DR: In this article, the synthesis of α-D-glucosides was performed by condensation of the newly prepared 3,4,7-tri-O-benzyl-2-deoxy-2p-toluenesulfonamido-5a-carba-α-DLglucopyranose with 1,6-di-O -acetyl- 2,3,4-tri -O-Benzylβ-Dglucophyranoses 2 in the presence of trimethylsilyl trif
10 citations
TL;DR: In this article, the optically active cyclitol, quebrachitol, was transformed into the known intermediate for preparation of (−)-isavenaciolide (2) for the first time.
Abstract: The naturally occurring optically active cyclitol, quebrachitol (1), was transformed into the known intermediate (17) for preparation of (–)-isoavenaciolide (2).
10 citations
TL;DR: The first total synthesis of the antibiotic validoxylamine G as its octa-acetate was reported in this paper, where the octaacetate is defined as the product of octa and octa.
Abstract: The first total synthesis of the antibiotic validoxylamine G as its octa-acetate is reported
9 citations
TL;DR: In this article, compound 3a has been shown to possess stronger inhibitory activity against α-glucosidase than methyl acarviosin 1 (MAC).
Abstract: Compound 3a has been shown to possess stronger inhibitory activity against α-glucosidase than methyl acarviosin 1.
TL;DR: In this paper, three stereoisomers of DL-1-C-(hydroxymethyl) conduritol epoxides have been synthesized in order to investigate their inhibitory activity against certain glycosyl hydrolases.
Abstract: Three stereoisomers of DL-1-C-(hydroxymethyl) conduritol epoxides have been synthesized in order to investigate their inhibitory activity against certain glycosyl hydrolases.
Journal Article•
TL;DR: In this paper, the optically active cyclitol, quebrachitol, was transformed into the known intermediate for preparation of (−)-isavenaciolide (2) for the first time.
Abstract: The naturally occurring optically active cyclitol, quebrachitol (1), was transformed into the known intermediate (17) for preparation of (−)-isoavenaciolide (2)
TL;DR: The (E)- and (Z)-isomers (2E and 2Z) of 3-O-benzyl-5,6-dideoxy-1,2-Oisopropylidene-α -D-xylo-hept-5-eno-1-4-furanose were subjected to Claisen rearrangement with triethyl orthoacetate as discussed by the authors.
Abstract: The (E)- and (Z)-isomers (2E and 2Z) of 3-O-benzyl-5,6-dideoxy-1,2-O-isopropylidene-α -D-xylo-hept-5-eno-1,4-furanose were subjected to Claisen rearrangement with triethyl orthoacetate. Possible two diastereomers were obtained as a 1 to 1 mixture from both of 2Z and 2E, and also from their 3-hydroxy or 3-siloxy derivatives. On the other hand, the rearrangement of the corresponding D-ribo derivative (13Z) and its 3-O-(t-butyldiphenylsilyl) derivative proceeded with a high level of diastereoselectivity. By contrast, the (E)-isomer of 13Z showed no significant stereoselectivity, resulting in the formation of a diastereomeric mixture. The configurations of the introduced stereogenic centers by the rearrangements were unambiguously established by chemical transformations.
TL;DR: A new synthesis of nojirimycin from seven-membered hemiacetal lactones derived from myo-inositol by a five-step reaction was reported in this paper.
Abstract: A report of a new synthesis of nojirimycin (1a), as well as its antipode (1b), from optically active seven-membered hemiacetal lactones (2a,b) derived from myo-inositol by a five step reaction; the hydrogen sulphite adduct of (1b) shows high inhibitory activity against β-glucosidase and α-mannosidase, being almost comparable to that of mannojirimycin.