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1.
宽叶秦岭藤根部的化学成分 总被引:6,自引:0,他引:6
通过正相和反相硅胶柱层析从宽叶秦岭藤根部乙醇提取物中分离纯化得到19个化合物,经波谱分析并结合化学方法鉴定了其结构,其中4个为新化合物,它们分别是3,5-二羟基二十烷酸羽扇豆醇酯(3),2-羟甲基-5-甲氧基苯基-O-β-D-吡喃葡萄糖甙(11),Δ5-孕甾烯-3β,20(S)-二醇-20-O-β-D-吡喃葡萄糖基(1→6)-β-D-吡喃葡萄糖甙(18,秦岭藤甙C)和Δ5-孕甾烯-3β,20(S)-二醇-3-O-β-D-吡喃葡萄糖基-20-O-β-D-吡喃葡萄糖基(1→6)-β-D-吡喃葡萄糖甙(19,秦岭藤甙D). 相似文献
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从仿刺参(Apostichopus japonicus Selenka)乙醇提取物中分离得到2个新的海参烷型皂苷类化合物,通过波谱数据分析并结合理化性质鉴定其分别为3β-O-{2-O-[3-O-甲基-β-D-吡喃葡萄糖-(1→3)-β-D-吡喃木糖-(1→4)-β-D-吡喃喹诺糖]-4-O-[β-D-吡喃葡萄糖]-β-D-吡喃木糖}-海参烷-7(8),25(26)-二烯-16-酮(化合物1,命名为Holotoxin E1)和3β-O-{2-O-[3-O-甲基-β-D-吡喃葡萄糖-(1→3)-β-D-吡喃木糖-(1→4)-β-D-吡喃葡萄糖]-4-O-[β-D-吡喃葡萄糖-(1→3)-β-D-吡喃葡萄糖]-β-D-吡喃木糖}-海参烷-7(8),25(26)-二烯-16-酮(化合物2,命名为Holotoxin E2).采用CCK-8法考察了包含上述2个新成分在内的共6个海参烷型皂苷对乳腺癌MDA-MB-231细胞和肝癌HepG2细胞的细胞毒活性.结果表明,除Holotoxin E2外,其余5种化合物对MDA-MB-231(I... 相似文献
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从棠梨枝叶(Pyrus pashia Buch.-Ham.ex D.Don)的甲醇提取物中分离得到了17个化合物,采用高分辨质谱、一维和二维核磁共振等现代波谱技术,鉴定上述化合物的结构分别为:pashinin A(1),天麻苷-7-O-顺式咖啡酸酯(2),天麻苷-7-O-反式咖啡酸酯(3),山奈酚-3-O-β-D-(6′′-O-对香豆酸酯)吡喃葡萄糖苷(4),山奈酚-3-O-β-D-(6′′-O-顺式对香豆酰)吡喃葡萄糖苷(5),天麻苷-7-O-对羟基苯甲酸酯(6),熊果苷(7),robustaside B(8),委陵菜酸(9),蔷薇酸(10),槲皮素3-O-β-D-吡喃葡萄糖苷(11),2R,3R-二氢槲皮素(12),木犀草素-4′-O-β-D-吡喃葡萄糖苷(13),芹黄素-4′-O-β-D-吡喃葡萄糖苷(14),5,7,4′-三羟基异黄酮-7-O-β-D-吡喃葡萄糖苷(15),染料木素(16),咖啡酸(17),其中化合物1和2为新化合物,化合物3为新的天然产物.除化合物17外,其余化合物均首次从该植物中分离得到.化合物1~3的抗肿瘤细胞活性实验表明其没有体外肿瘤细胞生长抑制活性(IC50>40μmol L-1);抗HIV病毒(HIV-1IIIB)实验显示:化合物1有极弱的抗HIV-1的活性,化合物4有弱的抗HIV-1的活性. 相似文献
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麦芽酚及麦芽酚-3-O-β-D-葡萄糖甙的合成 总被引:1,自引:0,他引:1
以乙酰丙酮(1)为原料,经溴代、酯化反应得到3-苯甲酰氧基-2,4-戊二酮(2),2与甲酸乙酯缩合、脱水闭环、酯水解得麦芽酚(3),总收率50.4%。3与a一溴代四乙酰化葡萄糖(4)经糖甙化、脱乙酰基得麦芽酚-3-O-β-D-葡萄糖甙(5),收率60.8%,IR,^1H NMR和^13C NMR确证5的葡萄糖为β-构型。中间产物2无须纯化,可实现“一锅”反应合成3。 相似文献
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从石竹科植物九子参(Silene rubicunda)根中得到四个糖链上带乙酰基的新的三萜皂苷——九子参苷A,B,C,D(rubicunosides A~D,1~4).前文已详细报道了九子参苷A的结构研究,本文报道九子参苷B,C,D的结构.通过FAB-MS和NMR,分别确定九子参苷B,C,D为糖链上带单乙酰基的三萜九糖苷、七糖苷和糖链上带双乙酰基的三萜八糖苷,分别命名为皂树酸-3-O-β-D吡喃半乳糖-(1→2)-[β-D-吡喃木糖-(1→3)]-β-D-吡喃葡萄糖醛酸-28-O-β-D-吡喃木糖-(1→3)-β-D-吡喃木糖-(1→4)-a-L-吡喃鼠李糖-(1→4)-[β-D-吡喃葡萄糖-(1→4′)-β-D-吡喃鸡纳糖-(1→2)]-[3′-O-乙酰基]-β-D-吡喃夫糖苷(九子参苷B,2),皂树酸-3-O-β-D-吡喃半乳糖-(1→2)-[β-D-吡喃木糖-(1→3)]-β-D-吡喃葡萄糖醛酸-28-O-β-D-吡喃木糖-(1→4)-a-L-吡喃鼠李糖-(1→4)-[4″-O-乙酰基-β-D-吡喃葡萄糖-(1→2)]-β-D-吡喃夫糖苷(九子参苷C,3),皂树酸-3-O-β-D-吡喃半乳糖-(1→2)-[β-D-吡喃木糖-(1→3)]-[6′-O-正丁基]-β-D-吡喃葡萄糖醛酸-28-O-β-D-吡喃木糖-(1→3)-β-D-吡喃木糖-(1→4)-a-L-吡喃鼠李糖-(1→4)-[2″-O-乙酰基-β-D-吡喃鸡纳糖-(1→2)]-[3′-O 乙酰基]-β-D-吡喃夫糖苷(九子参苷D,4). 相似文献
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用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%. 相似文献
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Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields. 相似文献
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A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL. 相似文献
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A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions. 相似文献
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Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction
Laurent Gavara Thomas Boisse Jean-Pierre Hénichart Adam Daïch Philippe Gautret 《Tetrahedron》2010,66(38):7544-5571
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments. 相似文献
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Uroš Grošelj Mojca Žorž Amalija Golobič Branko Stanovnik Jurij Svete 《Tetrahedron》2013,69(52):11092-11108
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives. 相似文献
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The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion. 相似文献
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Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular SN2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively. 相似文献
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The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula. 相似文献
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KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields. 相似文献