- Direct glycosylation of unprotected and unactivated sugars using bismuth nitrate pentahydrate
-
Bi(NO3)3, a low-cost, mild, and environmentally green catalyst, has been successfully utilized for Fischer glycosylation for the synthesis of alkyl/aryl glycopyranosides by reacting unprotected sugars, namely, D-glucose, L-rhamnose, D-galactose, D-arabinose, and N-acetyl-D-glucosamine with various alcohols in good to excellent yields. The glycosides were formed with high α-selectivity. Further, an expedient separation of α- and β-glycosides using silver nitrate-impregnated silica gel flash liquid chromatography has been developed.
- Polanki, Innaiah K.,Kurma, Siva H.,Bhattacharya, Asish K.
-
p. 196 - 205
(2015/06/08)
-
- The isolation and synthesis of two novel N-acetyl glucosamine derivatives from Dictyostelium cellular slime molds which exhibit neurite outgrowth activity
-
To clarify the diversity of secondary metabolites of Dictyostelium cellular slime molds and explore any biologically active substances which they may hold, constituents of two species were investigated. From a methanol extract of their fruit bodies, two novel acylated amino sugars were isolated, dictyoglucosamine A (1) from D. purpureum and dictyoglucosamine B (2) from D. discoideum. For further analysis, these compounds were then synthesized from N-acetyl-D-glucosamine. Biological evaluation of 1 and 2 showed they induce neuronal differentiation of rat pheochromocytoma (PC-12) cells.
- Kikuchi, Haruhisa,Komiya, Jun,Saito, Yoshinori,Sekiya, Jun-Ichi,Honma, Shigeyoshi,Nakahata, Norimichi,Oshima, Yoshiteru
-
p. 1477 - 1480
(2007/10/03)
-
- Furanodictine A and B: Amino sugar analogues produced by cellular slime mold Dictyostelium discoideum showing neuronal differentiation activity
-
We investigated the constituents of Dictyostelium discoideum to clarify the diversity of secondary metabolites of Dictyostelium cellular slime molds and to explore biologically active substances that could be useful in the development of novel drugs. From a methanol extract of the multicellular fruit body of D. discoideum, we isolated two novel amino sugar analogues, furanodictine A (1) and B (2). They are the first 3,6-anhydrosugars to be isolated from natural sources. Their relative structures were elucidated by spectral means, and the absolute configurations were confirmed by asymmetric syntheses of 1 and 2. These furanodictines potently induce neuronal differentiation of rat pheochromocytoma (PC-12) cells.
- Kikuchi,Saito,Komiya,Takaya,Honma,Nakahata,Ito,Oshima
-
p. 6982 - 6987
(2007/10/03)
-
- New α-selective thermal glycosylation of acetyl-protected 2-acetamido-2-deoxy-β-D-glucopyranosyl diphenylphosphinate
-
This paper describes new α-selective thermal glycosylation using acetyl-protected 2-acetamido-2-deoxy-β-D-glucopyranosyl diphenylphosphinate (4) as a glycosyl donor. When the glycosylation of 4 with 1-hexanol was carried out under various conditions, the conditions using trimethylsilyl trifluoromethanesulfonate as a promoter in nitromethane at reflux temperature were most suitable for the formation of the α anomer. The glycosylation of 4 with the other common alcohols gave corresponding α-glycosides in relatively high yields under the conditions. When cholesterol, a very steric hindered alcohol, was used as a glycosyl acceptor, α-glycoside was also produced predominantly. Copyright (C) 2000 Elsevier Science Ltd.
- Kadokawa, Jun-ichi,Nagaoka, Takeshi,Ebana, Jun,Tagaya, Hideyuki,Chiba, Koji
-
p. 341 - 344
(2007/10/03)
-
- Preparations and reactions of acylated and partially acylated glycosyl fluorides
-
Partial acylation of glycosyl fluorides in the galacto (2 and 3) and gluco series (8-10) is readily achieved. Attempts to further alkylate these acyl derivatives failed. Treatment of 2 with Lewis acid, however, provided a facile route to the 1,4-anhydro derivative 5. Lewis acid-mediated glycosylation of 2-acetamido-3,4,6-tri-O-acetyl-α-D-glucopyranosyl fluoride 11 led to the simple glycosides and thioglycosides 12-16. Similarly, in the galacto series (17) an advantageous route to the β-galactosidase inhibitor 19 could be elaborated.
- Thiem, Joachim,Wiesner, Matthias
-
p. 197 - 206
(2007/10/02)
-
- Ferric chloride, an anomerization catalyst for the preparation of alkyl α-glycopyranosides
-
Anhydrous FeCl3 in CH2Cl2 has been found to readily anomerize β-glycopyranosides to their corresponding α-anomers in good yields and selectivities at room temperatures. Acetyl- and benzoyl-protected oxygen sugars yielded the best results.
- Ikemoto, Norihiro,Kim, Oak Kyung,Lo, Lee-Chiang,Satyanarayana, Vunnam,Chang, Mayland,Nakanishi, Koji
-
p. 4295 - 4298
(2007/10/02)
-
- SYNTHESIS OF METHYL ETHERS OF METHYL 2-ACETAMIDO-2-DEOXY-α-D-GLUCOPYRANOSIDE
-
A convenient method is proposed for the synthesis of all the individual methyl ethers of methyl 2-acetamido-2-deoxy-α-D-glucopyranoside based on the partial methylation of 2-acetamido-2-deoxy-α-D-glucopyranoside with dimethyl sulfate in an alkaline medium followed by preparative liquid column chromatography on silica gel of the resulting mixture of methyl ethers.
- Evtushenko, E. V.,Plisova, E. Yu.,Ovodov, Yu. S.
-
p. 651 - 653
(2007/10/02)
-
- Synthesis and biological activity of some 1-N-substituted 2-acetamido-2-deoxy-beta-D-glycopyranosylamine derivatives and related analogs.
-
Several 1-N-substituted derivative [haloacetyl-, glycyl-, (dimethyl)amino-acetyl-, azidoacetyl-, trifluoroacetyl-, and trifluoromethylsulfonyl-] of 2-acetamido-2-deoxy-3,4,6-tri-O-acetyl-beta-D-glucopyranosylamine (1) were synthesized as potential metabolic inhibitors of cellular-membrane glycoconjugates. Several fully acetylated derivatives were found to inhibit growth of mouse mammary adenocarcinoma TA3, leukemia L1210, or leukemia P-288 cells at 1-0.01 mM concentration in vitro. Some of these derivatives were less active after O-deacetylation. Analogs of 1 in which NH2-1 was replaced by OH- or OAc-1 were also active on the same cell systems. The growth-inhibitory activity was correlated with inhibition of the incorporation of 2-amino-deoxy-D-glucose and L-leucine into a macromolecular fraction.
- Paul,Bernacki,Korytnyk
-
-