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1.
β-Glycosides of 2-acetamido-2-deoxy-
-glucopyranose were synthesized, using either 7-methoxycarbonyl-3,6-dioxa-1-heptanol or 8-azido-3,6-dioxa-1-octanol. Selective β-lactosylation of 7-methoxycarbonyl-3,6-dioxaheptyl 2-acetamido-3-O-benzyl-2-deoxy-β-
-glucopyranoside with hepta-O-acetyl-lactosyl-trichloroacetimidate, followed by β-galactosylation of the secondary hydroxyl group with O-(2,3,4,6-tetra-O-acetyl--
-galactopyranosyl)trichloroacetimidate, catalytic hydrogenolysis, and O-deacetylation, gave 7-methoxycarbonyl-3,6-dioxaheptyl 2-acetamido-2-deoxy-4-O-β-
-galactopyranosyl-6-O-(4-O-β-
-galactopyranosyl-β-
-glucopyranosyl)β-
-glucopyranoside. Selective β-lactosylation of 8-azido-3,6-dioxaocytl 2-acetamido-3-O-benzyl-2-deoxy-β-
-glucopyranoside with hepta-O-acetyl-lactosyl bromide in the presence of silver triflate, followed by condensation with 2,3,4,6-tetra-O-acetyl--
-galactopyranosyl bromide in the presence of silver triflate, catalytic hdyrogenolysis, and O-deacetylation, gave 8-azido-3,6-dioxaoctyl 2-acetamido-2-deoxy-4-O-β-
-galactopyranosyl-6-O-(4-O-β-
-galactopyranosyl-β-
-glucopyranosyl)-β-
glucopyranoside. 相似文献
2.
Otilia D. L. Pessoa Telma L. G. De Lemos M rio G. De Carvalho Raimundo Braz-Filho 《Phytochemistry》1995,40(6):1777-1786
Further cordiachromes, rel-10,11β-epoxy-11-ethoxy-8-hydroxy-2-methoxy-8aβ-methyl-5,6,7,8,8a,9,10aβ-octahydro-1,4-anthracendione, 6-formyl-2-methoxy-9-methyl-7,8-dihydro-1,4-phenanthrendione, rel-8,11;9,11-diepoxy-1,4-dihydroxy-2-methoxy-8aβ-methyl-5,6,7,8,8a,9,10,10aβ-octahydro-10-anthracenone, rel-9,11-epoxy-1,4,8-trihydroxy-2-methoxy-8aβ-methyl-5,6,7,8,8a,9,10,10aβ-octahydro-10-anthracenone, rel-2″-methoxy-7″-methyl-1″,4″-naphtalendione-(6″→5)-tetrahydropyran-(2-eq→O→2ax)-tetrahydropyran-(5′→6)- 2-methoxy-7-methyl-1,4-naphthalendione, together with the known, allantoin, sitosterol and 3β-O-d-glucopyranosylsitosterol, have been isolated from Auxemma oncocalyx. Their structures were determined from spectral data, including 2D NMR experiments. 相似文献
3.
Chalconoid and stilbenoid glycosides from Guibourtia tessmanii 总被引:2,自引:0,他引:2
Fuendjiep V Wandji J Tillequin F Mulholland DA Budzikiewicz H Fomum ZT Nyemba AM Koch M 《Phytochemistry》2002,60(8):1091-806
Phytochemical studies on the stem bark of Guibourtia tessmanii yielded a dihydrochalcone glucoside, 2′,4-dihydroxy-4′-methoxy-6′-O-β-glucopyranoside dihydrochalcone and a new stilbene glycoside, 3,5-dimethoxy-4′-O-(β-rhamnopyranosyl-(1→6)-β- glucopyranoside) stilbene besides the known pterostilbene. Their structures were established on the basis of one and two dimensional NMR spectroscopic techniques, FABMS and chemical evidence. 相似文献
4.
Manuel Alonso-Lopez Manuel Bernabe Alfonso Fernandez-Mayoralas Jesus Jimenez-Barbero Manuel Martin-Lomas Soledad Penades 《Carbohydrate research》1986,150(1):103-109
The reaction of benzyl 2,6,6′-tri-O-benzyl-3′,4′-O-isopropylidene-β-lactoside with 1,11-ditosyloxy-3,6,9-trioxaundecane gave benzyl 2,6,6′-tri-O-benzyl-3′,4′-O-isopropylidene-3,2′-O--(3,6,9-trioxaundecane-1,11-diyl)-β-lactoside (2, 47%). Acid hydrolysis of 2 and condensation of the product with 1,14-ditosyloxy-3,6,9,12-tetra-oxatetradecane afforded benzyl 2,6,6′-tri-O-benzyl-3′,4′-O-(3,6,9,12-tetraoxa-tetradecane-1,14-diyl)-3,2′-O-(3,6,9-trioxaundecane-1,11-diyl)-β-lactoside (29%). Similarly, the reaction of benzyl 2,6,2′,4′,6′-penta-O-benzyl-β-lactoside with Ts[OCH2CH2]4OTs gave benzyl 2,6,2′,4′,6′-penta-O-benzyl-3,3′-O-(3,6,9-trioxaundecane-1,11-diyl)-β-lactoside (78%). 1H-N.m.r. spectroscopy has been used to study the formation of host-guest complexes with some of these macrocyclic compounds and benzyl ammonium thiocyanate. 相似文献
5.
Three acylated flavonol diglucosides, kaempferol 3-O-β-(6″-O-E-p-coumaroylglucoside)-7-O-β-glucoside; quercetin 3-O-β-(6″-O-E-p-coumaroylglucoside)-7-O-β-glucoside; isorhamnetin 3-O-β-(6″-O-E-p-coumaroylglucoside)-7-O-β-glucoside were isolated from the whole plant aqueous alcohol extract of Lotus polyphyllos. The known 3,7-di-O-glucosides of the aglycones kaempferol, quercetin and isorhamnetin were also characterized. All structures were established on the basis of chemical and spectral evidence. 相似文献
6.
Minowa N Akiyama Y Hiraiwa Y Maebashi K Usui T Ikeda D 《Bioorganic & medicinal chemistry letters》2006,16(24):6351-6354
Synthesis and activity of derivatives at the O5 or O6 positions of 1-N-((S)-4-amino-2-hydroxybutyryl)-3′,4′-dideoxyneamine, which is the neamine moiety of arbekacin, were reported. Among these results, the 5-O-aminoethylaminocarbonyl derivative showed effective activity against Staphylococcus aureus expressing a bifunctional aminoglycoside-modifying enzyme AAC(6′)-APH(2″). 相似文献
7.
Azefack Leon Tapondjou Ngninzeko Fernande Ngounou David Lontsi Beibam Lucas Sondengam Marie-Therese Martin Bernard Bodo 《Phytochemistry》1995,40(6):1761-1764
From the methylated trunk wood extracts of Myrianthus liberecus, six pentacyclic triterpenes have been isolated as their methyl esters. These included the known methyl benthamate, methyl euscaphate, methyl tormentate, methyl arjunolate, methyl 3-isoarjunolate and methyl 3β-O-(4″-O-methyl-E-coumaroyl)-arjunolate, a new triterpene derivative. 相似文献
8.
Stephen J. Bloor 《Phytochemistry》1999,50(8):1242-1399
The blue colour of the petals of the blue marguerite daisy, Felicia amelloides, has been found to arise from copigmentation between a novel malonylated delphinidin triglycoside, delphinidin 3-O-neohesperidoside 7-O- (6-O-malonyl-glucoside), and a new flavone C-glycoside, swertisin 2″-O-rhamnoside-4′-O-glucoside. Recombination, in vitro, of these two petal components at pH 6 recreates the blue petal colour. 相似文献
9.
Pierluigi Gariboldi Francesca Pelizzoni Marco Tat Luisella Verotta Nadia El-Sebakhy Aya M. Asaad Rokia M. Abdallah Soad M. Toaima 《Phytochemistry》1995,40(6):1755-1760
Three new cycloartane glycosides, trigonoside I, II and III, and the known astragalosides I and II were isolated from the roots of Astragalus trigonus. The structures of the new glycosides were totally elucidated by high field (600 MHz) NMR analyses as cycloastragenol-6-O-β-xylopyranoside, cycloastragenol-3-O-[-l-arabinopyranosyl(1 → 2)-β-d-xylopyranosyl]-6-O-β- d-xylopyranoside and cycloastragenol-3-O-[-l-arabinopyranosyl(1 → 2)-β-d-(3-O-acetyl)-xylopyranosyl]-6-O-β-d-xylopyranoside. 相似文献
10.
Two iridoid glucosides, 8-epi-grandifloric acid and 3′-O-β-glucopyranosyl-stilbericoside, were isolated from the aerial part of Thunbergia laurifolia along with seven known compounds, benzyl β-glucopyranoside, benzyl β-(2′-O-β-glucopyranosyl) glucopyranoside, grandifloric acid, (E)-2-hexenyl β-glucopyranoside, hexanol β-glucopyranoside, 6-C-glucopyranosylapigenin and 6,8-di-C-glucopyranosylapigenin. Strucural elucidation was based on the analyses of spectroscopic data. 相似文献
11.
Three main saponins were isolated from the seeds of Albizzia lucida. Their structures were established by spectral analyses and chemical and enzymatic transformations as 3-O-[β-
-xylopyranosyl(1→2)--
-arabinopyranosyl (1→6)] [β-
-glucopyranosyl (1→2)] β-
-glucopyranosyl echinocystic acid; 3-O-[-
-arabinopyranosyl (1→6)][β-
-glucopyranosyl (1→2)]-β-
-glucopyranosyl echinocystic acid and 3-O-[β-
-xylopyranosyl (1→2)-β-
-fucopyranosyl (1→6)-2-acetamido-2-deoxy-β-
-glucopyranosyl echinocystic acid, characterized as its methyl ester. 相似文献
12.
From the mesocarp of Balanites aegyptiaca fruits, two pregnane glycosides were isolated. One is new and identified as pregn-5-ene-3β,16β,20(R)-triol 3-O-(2,6-di-O--l-rhamnopyranosyl)-β-d-glucopyranoside (balagyptin), while the other is known and assigned as pregn-5-ene-3β,16β,20(R)-triol 3-O-β-d-glucopyranoside. 相似文献
13.
Andr s Lipt k Lajos Szab J nos Ker kgy rt J nos Harangi P l N n si
Helmut Duddeck
《Carbohydrate research》1986,150(1):187-197The title tetrasacharide having the structure 3-O-Me-β-
-Xylp-(1→4)--
-Rhap-(1→4)--
-Rhap-(1→2)-
-Rhap was obtained by reaction of the -acetobromo derivative of 4-O-(3-O-methyl-β-
-xylopyranosyl)-
-rhamnopyranose and benzyl 3,4-di-O-benzyl-2-O-(2,3-O-isopropylidene--
-rhamnopyranosyl)--
-rhamnopyranoside, followed by removal of the protecting groups. The synthesised compounds were characterised on the basis of n.m.r. data. 相似文献
14.
Yi Yang-Hua 《Phytochemistry》1991,30(12):4179-4181
A new triterpenoid, esculentagenin, and its glycoside, esculentoside M, were isolated from the roots of Phytolacca esculenta and characterized as 11-oxo-3-O-methyloleanata-12-en-2β,3β,23-trihydroxy-28-oic acid and 3-O-[β -
-glucopyranosyl (1→4)-β-
-Xylopyranosyl]-28-O-β-
-glucopyranosyl-11-oxo-30-methyloleanate-12-en-2β,3β,23-trihydroxy-28-oic acid by spectral and chemical evidence. 相似文献
15.
Oligosaccharides not previously recorded in the Cladophorales (green algae) have been separated from the 80% ethanolic extract and characterised. 4-O-Lactyl-β-
-fructofuranosyl -
-glucopyranoside (sucrose lactate) was found only in Cladophora laetevirens and a fresh-water Rhizoclonium species. Panose, maltotriose, maltotetraose, and 6-O-
-glucosylmaltotriose appear to be common to all the species examined1. 相似文献
16.
Mark A. Berhow Raymond D. Bennett Katherine Kanes Stephen M. Poling Carl E. Vandercook 《Phytochemistry》1991,30(12):4198-4200
A malonic acid ester derivative of the flavanone naringin was abundant in the young leaves and fruits of grapefruit plants, but not in the mature leaves and fruits. After isolation, the structure of this compound was established as naringin 6″-malonate (naringenin 72″-O--
-rhamnosyl)-β-
-glucoside 6″-malonate). 相似文献
17.
18.
Guilherme L. Sassaki Julio C. Ferreira Chirlei Glienke-Blanco Giangiacomo Torri Fabiana De Toni Philip A. J. Gorin Marcello Iacomini 《Carbohydrate polymers》2002,48(4):177-389
Guignardia citricarpa is a phytopathogenic fungus and the causal agent of citrus black spot. Incubation in a semi-defined media resulted in formation of exopolysaccharides [EPS(s)]. A medium containing glucose gave rise to a (1→6)-linked β-glucan (200 kD), pustulan, which was characterized by NMR and methylation analysis. A sucrose-containing medium provided a homogalactan (376 kD) and methylation analysis showed nonreducing end- (20%), 6-O- (53%) and 5,6-di-O-substituted Galf units (27%). An HMQC spectrum of the homogalactan showed C-1/H-1 signals at δ 108.2/4.820, 108.3/4.820 and 107.1/5.079, corresponding to three types of β-
-Galf units. A DEPT analysis showed inverted signals (CH2) at δ 67.8 and 67.2, corresponding to 6-O-substituted β-
-Galf units, whereas a C-5 signal at δ 77.0 suggests 5-O-substitution, confirming a novel structure for a β-galactofuranan. 相似文献
19.
Synthesis of a series of ganglioside GM3 analogs containing a deoxy-N-acetylneuraminic acid residue.
Akira Hasegawa Keisuke Adachi Masahiro Yoshida Makoto Kiso 《Carbohydrate research》1992,230(2):273-288
Ganglioside GM3 analogs containing 4-, 7-, 8-, and 9-deoxy-N-acetylneuraminic acids in the place of N-acetylneuraminic acid (Neu5Ac) have been synthesized. Glycosylation of 2-(trimethylsilyl)ethyl O-(6-O-benzoyl-β-
- galactopyranosyl)-(1 → 4)-2,6-di-O-benzoyl-β-
-glucopyranoside with the methyl 2-thioglycoside derivatives of the respective deoxy-N-acetylneuraminic acids, using dimethyl(methylthio)sulfonium triflate as a promoter, gave the four required 2-(trimethylsilyl)ethyl -sialosyl-(2 → 3b)-β-lactosides. These were converted via O-acetylation, selective removal of the 2-(trimethylsilyl)ethyl group, and subsequent imidate formation, into the corresponding -sialosyl-(2 → 3b)--lactose trichloroacetimidates 15, 17, 19, and 21. Glycosylation of (2S,3R,4E)-2-azido-3-O-benzoyl-4-octadecene-1,3-diol with 15, 17, 19, and 21 in the presence of boron trifluoride etherate afforded the expected β glycosides, which were transformed in good yields, via selective reduction of the azido group, coupling with octadecanoic acid, O-deacylation, and de-esterification, into the target compounds. 相似文献
20.
Lubomír Kremnický Vladimír Mastihuba Gregory L. Ct 《Journal of Molecular Catalysis .B, Enzymatic》2004,30(5-6):229-239
Partially purified Trichoderma reesei RUT-C30 acetyl esterase preparation was found to catalyze acyl transfer reactions in organic solvents, mixtures of organic solvents with water and even in water. Using different acyl donors, the best results for acetyl transfer in water were obtained using vinyl acetate. As acetyl acceptors, a variety of hydroxyl bearing compounds in aqueous solutions were used. Degree of conversion and the number of newly formed acetates varied according to the acceptor used. Conversions over 50% were observed for the majority of several common monosaccharides, their methyl and deoxy derivatives and oligosaccharides. In several cases, the transesterification reaction exhibited strict regioselectivity, leading to only one acetyl derivative. Preparative potential of the transesterification in water was demonstrated by acetylation of methyl β-
-glucopyranoside, 4-nitrophenyl β-
-glucopyranoside and kojic acid, yielding 56.4% of methyl 3-O-acetyl β-
-glucopyranoside, 70.2% of 4-nitrophenyl 3-O-acetyl β-
-glucopyranoside and 30.9% of 7-O-acetyl-kojic acid as the only reaction products.
This enzymatically catalyzed transacetylation in water, which is applied to transformation of saccharides for the first time, opens a new area in chemoenzymatic synthesis. Its major advantages are simplicity, highly regioselective esterification of polar compounds, high yields, low enzyme consumption and elimination of the need to use toxic organic solvents. 相似文献