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相转移催化法合成1-O-酰基-四-O-乙酰基-β-D-吡喃己糖 总被引:10,自引:0,他引:10
以氯化三乙基苄基铵作为相转移催化剂, 用2, 3, 4, 6-四-O-乙酰基-β-D-溴代吡喃葡萄糖和2, 3, 4, 6-四-O-乙酰基-β-D-溴代吡喃半乳糖与羧酸反应, 合成了相应的1-O-酰基-2, 3, 4, 6-四-O-乙酰基-β-D-吡喃葡萄糖和半乳糖。通过解析这些化合物的^1H NMR和红外光谱, 确证其糖甙键构型为β。该相转移催化法具有反应条件温和, 后处理简单和立体选择性强等优点。 相似文献
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糖酯类化合物具有广泛的生理活性,如抗菌、抗肿瘤等。1987年Trivedi等首次使用苯甲酰基保护的溴化α-D-葡萄糖与桂皮酸类在相转移催化剂三甲基十六烷基溴化铵的存在下反应,合成了收率为53%~82%的糖酯,此结果与Inch的结果不一致。我们在前文的基础上用2,3,4,6-四-O-乙酰基-α-D-溴代吡喃葡萄糖(1)与桂皮酸类(2~5)及与苯甲酸类(10~16),在催化剂四丁基溴化铵的存在下反应,合成了糖酯(6~9,17~23),收率为58%~82%。产品具有高度的立体选择性,~1H NMR的化学位移δ值在5.89~6.01,偶合常数J:7.2~8.1Hz,1R光谱在902.2 cm~(-1)左右具有特征吸收峰,证实为β端基异构体。 相似文献
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2,3,4,6-四-O-乙酰基-β-D-吡喃葡萄糖基异硫氰酸酯的合成及晶体结构 总被引:1,自引:0,他引:1
采用葡萄糖作原料经乙酰化、溴化和硫氰酸化三步合成了2,3,4,6-四-O-乙酰基-β-D-吡喃葡萄糖基异硫氰酸酯,培养出了单晶,用X射线衍射分析了其晶体结构.结果表明,晶体为正交晶系,P212121空间群,a=0.72624(2)nm,b=1.17508(2)nm,c=2.17210(5)nm,α=β=γ=90°,V=1.85365(7)nm,Z=4,R=0.0531,wR=0.1359. 相似文献
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l-O-Aroyl-β-D-glucopyranose tetraacetates (Ⅰ -Ⅶ) were obtained by the condensation of tetra-O-acetyl-α-ZJ-glucopyranosyl bromide with aromatic acids in K2CO3-Me2CO at room temperature. Exclusive production of β-D-anomers was confirmed by measurement of their specific rotation and also by observing their 1R and NMR spectra. Reaction of α-acetobromoglucose with methyl o- or p-hydroxybenzoate in aq. KOH-Me2CO gives the corresponding β-D-glucopyranoside(Ⅶ- Ⅷ). Control of the stereochemistry in obtaining α-D-anomers (Ⅷ-Ⅸ ) could also be satisfactorily achieved by employing penta-O-acetyl-D-glucopyranose and methyl o- or p- hydroxybenzoate in ZnG2-AcOH-Ac2O. 相似文献
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1-脱氧-1-氨甲基-4,6-O-亚苄基-β-D-吡喃葡萄糖是合成糖碳苷类糖肽的重要潜在中间体.本文以无水D-葡萄糖为原料经过两步反应合成1-脱氧-1-硝基甲基-4,6-O-亚苄基葡萄糖,然后通过催化转移氢化反应选择性地对硝基进行还原而不影响4,6位的亚苄基. 相似文献
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The isomerization products of fac- and mer-[Co(β-ala)_3] in neutral and acidic media were separated with Na~+-type SP-Sephaex C-25 column and determined by spectrophotometry. At high temperatures(>90 ℃)the fac-isomer readily isomerizes to mer-[Co(β-ala)_3] and simultaneously hydrolyzes to yield a brown slurry in neutral solution.However, in acidic solution hydrolysis does not occur, the products are mer-isomer and a small amount of red complex cation, which is strongly adsorbed at the top of SP-Scphadex column and would probably be the fac-[Co(β-ala)_2[Co(β-alaH)(H_2O]~+.At 90 ℃ the mer-[Co(β-ala)_3]is hydrolyzed rapidly to yield a brown precipitate in neutral solution and isomerizes in small amount to fac-isomer. In acidic solution the mer-isomer isomerizes slightly to fac-isomer, and at the top of SP-Sephadex column, a violet complex cation which would probably be mer-[Co(β-ala)_2(β-alaH)(H_2O]~+ is abserved.The kinetic parameters of isomerization of fac-[Co(β-ala)_3] in neutral, basic and acidic solutions have been determined with spectrophotometric method at 534 nm. The resufts obtained indicate that reaction rates v with respect to fac-[Co(β-ala)_3] in neutral, basic and acidic media are all in first order, and under constant initial concentration of fac-[Co(β-ala)_3] the reaction rates v with respect zation of fac-[Co(β-ala)_3] in neutral, [OH~-]=4.04×10~(-4) molL~(-1), [HCl]=1.56×10~(-2) molL~(-1) and [HClO_4]=1.56×10~(-2) molL~(-1) media at 90 ℃ are 0.0195, 57.3, 3.43 and 0.978 min~(-1) while the activation energies are 194.2, 103.1, 134.1 and 113.8 kJ.mol~(-1) respectively. 相似文献
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Arun K. Sarkar Sushama M. Pawar Khushi L. Matta 《Journal of carbohydrate chemistry》2013,32(2):269-278
ABSTRACT Synthesis of three tetrasaccharides, namely, 0-α-L-fucopyranosyl-(1→3)-0-(2-acetamido-2-deoxy-β-D-glucopyranosyl)-(1→3)-0-(β-D-galactopyranosyl)-(1→4)-β-D-glucopyranose (7), 0-α-L-fucopyranosyl-(1→4)-0-(2-acetamido-2-deoxy-β-D-glucopyranosyl)-(1→3)-0-(β-D-galactopyranosyl)-(1→4)-D-glucopyranose (9), and 0-α-L-fucopyransoyl-(1→3)-0-(2-acetamido-2-deoxy-β-D-glucopyransoyl)-(1→6)-0-(β-D-galactopyranosyl)-(1→4)-D-glucopyranose (15) has been described. Their structures have been established by 13C NMR spectroscopy. 相似文献
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在微波作用的无溶剂条件下,由4β-叠鬼臼毒素与炔烃反应,合成了8个含有 1,2,3-三唑的鬼臼毒素衍生物,并用IR, ~1H NMR, MS确定了这些化合物的结构。 该反应操作简单,产率较高,副产物少,同时具有原子经济性。 相似文献
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2,6-Dimethyl- and 2,6-dimethoxy-α-methoxycarbonyl-α-trifluoromethyl-p-methylenequinones have been synthesized. These compounds easily react with ammonia, morpholine, andp-toluidine to afford the corresponding α-(4-hydroxyphenyl)-β,β,β-trifluoro-α-alanine derivatives. 相似文献
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Staudinger 反应是合成β-内酰胺类化合物最重要的方法之一. 3-(噻吩-2-基)-β-内酰胺是一类重要的β-内酰胺类衍生物. 发展了一种从1-(噻吩-2-基)-4,4,4-三氟-1,3-丁二酮和对甲苯磺酰叠氮方便地制备1-(噻吩-2-基)-2-重氮基乙酮的新方法, 利用1-(噻吩-2-基)-2-重氮基乙酮加热分解生成的噻吩-2-基烯酮参与的Staudinger反应合成了一系列3-(噻 吩-2-基)-β-内酰胺衍生物, 并研究了噻吩-2-基烯酮参与的Staudinger反应的立体选择性. 实验结果表明噻吩-2-基烯酮是比苯基烯酮更富电子的Moore烯酮, 其电子性质介于对甲氧基苯基烯酮和对甲基苯基烯酮之间. 相似文献
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Jun Ying LIU Yi Yang DONG Tian Song WANG Hu Wei LIU Al Jin HUANG yi Liang SUNI Zeng Pei SUN 《中国化学快报》1999,10(1):39-42
IntroductionChaedcyclodextrlnswerefirstIntroducedby几rabelforchlralseparationofamlnoacids,andthechargedCDcommonlyusednowdaysarecarboxymethyl-p-CD(CM-p-CD),p-CD-phosphate,Y-CD-phosphate,sulfobutylether-p-cyclodextrln(SBE-p-CD)etc.... 相似文献
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三氯锗丙酰氯与(R)-四氢噻唑-2-硫酮-4-羧酸甲酯反应, 得到标题化合物1, [α]~D^2^0-89.40°。经水解得到取代丙酰四氢噻唑-2-硫酮-4-羧酸甲酯基锗倍半氧化物2, X射线衍射法测出标题化合物的晶体结构, 属于正交晶系, 晶胞参数: a=0.6192(1)nm,b=1.1147(4)nm,c=2.1796(8)nm, V=1.5045nm^3, Z=4, 空间群P2~12~12~1。分子中酰胺羰基C=O与C=S基团处于C(4)NC(3)键两侧呈反式。用MNDO分子轨道方法研究了该化合物的电子结构, 电荷和键序分布,前沿轨道性质,讨论了电子光谱性质。 相似文献
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Zhenguang Lin Yingdi Mu Yihui Liu Yeming Ren Jimao Lin 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2010,75(3):1159-1162
The structure of (1α, 2β, 4β, 5α, 7β)-7-[(hydroxydi-2-thienylacetyl) oxy]-9,9-dimethyl-3-oxa-9-azoniatricyclo [3.3.1.02,4] nonane bromide monohydrate was studied using 1D and 2D NMR techniques. Complete NMR assignments of the compound were obtained using DEPT, H–H COSY, as well as HMQC and HMBC heteronuclear correlation techniques. 相似文献
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《中国化学快报》2022,33(9):4345-4349
Phosphorylated di-, tri- and tetra-saccharides of β-1,2-mannan antigen derived from Candida albicans (C. albicans) cell wall were synthesized and covalently conjugated with keyhole limpet hemocyanin (KLH) and human serum albumin (HSA) via a bifunctional linker under mild conditions. The semi-synthetic β-1,2-mannoside–KLH conjugates were evaluated for the immunization of BALB/c mice. The ELISA results revealed that all three conjugates could elicit high levels of specific IgG antibodies and the acquired antisera could effectively identify the β-1,2-mannan epitope. Furthermore, the immunofluorescence and flow cytometry assays also uncovered that the induced antibodies, especially that obtained from immunization with β-1,2-mannotriose–KLH conjugate (1b), could bind well to fungi cell. Eventually, the structure–immunogenicity relationship analysis of β-mannan showed that the length of oligo-β-mannoses had a big impact on their immunogenicity and β-1,2-mannotriose showed the strongest immunogenicity. The results suggested the great potential of β-1,2-mannotriose–KLH conjugate as an antifungal vaccine candidate. 相似文献