鲜人参中2种丙二酰基人参皂苷的分离鉴定

采用硅胶柱层析方法,流动相分别为氯仿-甲醇-水(65∶35∶10,V/V)、氯仿-甲醇-水(6∶4∶1)和正丁醇-乙酸乙脂-甲醇-水(4∶2∶1∶1)和高效液相(Nuc leosil C18(250 mm×10 mm,5μm)色谱柱;流动相为己腈-水(75∶25);流速为3.0 mL/m in;柱温30℃;检测波长203 nm。从中国鲜人参中分离得到丙二酰基人参皂苷R c和丙二酰基人参皂苷Rb2,并通过其理化性质、红外光谱、质谱和核磁共振谱对化合物的结构进行了鉴定,证明其结构分别为3-O-[6-O-丙二单酰-β-D-葡萄吡喃糖(1→2)-β-D-葡萄吡喃糖]-20-O-[α-L-阿拉伯呋喃糖(1→6)-β-D-葡萄吡喃糖]-20(S)-原人参二醇和3-O-[6-O-丙二单酰-β-D-葡萄吡喃糖(1→2)-β-D-葡萄吡喃糖]-20-O-[α-L-阿拉伯吡喃糖(1→6)-β-D-葡萄吡喃糖]-20(S)-原人参二醇;丙二酰基人参皂苷R c为首次从中国鲜人参中分得。     

2,6-二甲基-3,5-二氯-4-吡啶酚糖苷的合成

在相转移催化条件下, 使 a-D-乙酰基化溴代的葡萄糖、半乳糖、葡萄糖醛酸甲酯1a, 1b, 1c分别与2,6-二甲基-3,5-二氯-4-吡啶酚(俗称氯吡醇, 氯羟吡啶)作用, 合成了氯吡醇的糖苷: 1-O-(2',6'-二甲基-3',5'-二氯-4'-吡啶基)-2,3,4,6-四-O-乙酰基-β-D-葡萄吡喃糖苷(2a), 1-O-(2',6'-二甲基-3',5'-二氯-4'-吡啶基)-2,3,4,6-四-O-乙酰基β-D-半乳吡喃糖苷(2b), 1-O-(2'6'-二甲基-3',5'-二氯-4'-吡啶基)-2,3,4-三-O-乙酰基-β-D-葡萄吡喃糖醛酸甲酯(2c)。2a, 2b, 2c分别在甲醇中氨解, 相应得到: 1-O-(2', 6'-二甲基-3',5'-二氯-4'-吡啶基)-β-D-葡萄吡喃糖苷(3a), 1-O(2',6'-二甲基-3',5'-二氯-4'-吡啶基)-β-D-半乳吡喃糖苷(3b),1-O-(2', 6'-二甲基-3',5'-二氯-(4'-吡啶基)-β-D-葡萄吡喃糖醛酸酰胺(3c)。2c用CH~3ONa/CH~3OH处理, 得到1-O-(2',6'-二甲基-3',5'-二氯-4'-吡啶基)-β-D-葡萄吡喃糖醛酸甲酯(3d)。     

十二烷基β-D-葡萄吡喃糖基-(1→3)-[β-D-葡萄吡喃糖基-(1→6)]-β-D-葡萄吡喃糖基-(1→6)-β-D-葡萄吡喃糖苷的合成

本文以3-O-烯丙基-6-O-乙酰基-2,4-二-O-苯甲酰基-α-D-葡萄糖三氯乙酰亚氨酯1为原料,设计合成了尚未见报道的十二烷基β-D-葡萄吡喃糖基-(1→3)-[β-D-葡萄吡喃糖基-(1→6)]-β-D-葡萄吡喃糖基-(1→6)-β-D-葡萄吡喃糖苷6。其组成和结构已由元素分析、1H NMR、13C NMR表征。     

黄花棘豆化学成分的研究Ⅱ.两种三萜皂苷的结构

从黄花棘豆的总皂苷中分离出两个新皂苷1和2。经光谱分析及化学方法确证,1为3-O-[α-L-鼠李吡喃糖基(1→2)-β-D-葡萄吡喃糖基(1→4)-β-D-葡萄吡喃糖醛酸基]-黄豆醇B;2为3-O-[α-L-鼠李吡哺糖基(1→2)-α-L-阿拉伯吡哺糖基(1→4)-β-D-葡萄吡喃糖醛酸基]-黄豆醇B。     

黄花棘豆化学成分的研究II:两种三萜皂苷的结构

从黄花棘豆的总皂苷中分离出两个新皂苷1和2.经光谱分析及化学方法确证,1为3-O-[α-L-鼠李吡喃糖基(1→2)-β-D-葡萄吡喃糖基(1→4)-β-D-葡萄吡喃糖醛酸基]-黄豆醇B;2为3-O-[α-L-鼠李吡喃糖基(1→2)-α-L-阿拉伯吡喃糖基(1→4)-β-D-葡萄吡喃糖醛酸基]-黄豆醇B.     

断节参甙的结构

从断节参根的粗甙中分离得到一个新甙——断节参甙(wallicoside,6).经光谱数据及降解反应证明其结构为告达庭-3-O-β-D-葡萄吡喃糖基-(1→4)-β-D-葡萄吡喃糖基-(1→4)-β-D-夹竹桃吡喃糖基-(1→4)-β-D-加拿大麻吡喃糖基-(1→4)-β-D-加拿大麻吡喃糖甙.     

超分子体系中的分子识别研究37.几种磷酰基修饰β-环糊精对染料分子的识别

通过乙氧基-N,N-乙基磷酰氯与β-环糊精直接反应合成了单-[6-O-(二乙氨基-乙氧基)-磷酰基-β-环糊精(3)采用荧光光谱和紫外光谱滴定法测定了化合物(3)与结构相关的两种磷酰基修饰β-环糊精单-[6-O-(二苯氧基)-磷酰基]-β-环糊精(1),单-[6-O-(乙氧基羟基)-磷酰基]-β-环糊精(2),与一系列染料分子在磷酸缓冲溶液(pH7.20,0.1 mol·     

超急免疫排斥反应抑制相关寡糖二聚物的合成研究

首次报道了3,6-二氧代辛基-1,8-二-O-{4-O-[(3-O-a-D-吡喃半乳糖基)-β-D-吡喃半乳糖基]-2-脱氧-2-乙酰氨基-β-D-吡喃葡萄糖苷}(1)的合成，运用三氯乙酰亚胺酯法，通过控制反应条件，成功地实现了选择性、高收率地合成三糖PEG二聚物或其单苷化合物，并对成苷条件进行了深入的研究。     

天然黄酮香叶木素类及其衍生物的合成与生物活性研究

以橙皮苷为原料,经脱氢、选择性甲基化、糖苷水解、相转移催化下的糖苷化反应、异戊烯基化和法呢烯基化等反应步骤,分别合成了3’-O-甲基香叶木素(1),香叶木素-7-O-β-D-葡萄糖苷(2),香叶木素-7-O-β-D-半乳糖苷(3),3’-O-甲基香叶木素-7-O-β-D-葡萄糖苷(4)4种天然产物及3’-O-甲基香叶木素-7-O-β-D-半乳糖苷(5),香叶木素-7-O-β-D-乙酰葡萄糖苷(6)、香叶木素-7-O-β-D-乙酰半乳糖苷(7),3’-O-甲基香叶木素-7-O-β-D-乙酰葡萄糖苷(8),3’-O-甲基香叶木素-7-O-β-D-乙酰半乳糖苷(9),7-O-异戊基香叶木素(10),7-O-异戊烯基-3’-O-甲基香叶木素(11)和7-O-法呢烯基-3’-O-甲基香叶木素(12)8种新的香叶木素衍生物.所合成化合物的结构已由核磁共振谱、红外光谱和质谱所证实,并用比色法MTT[3-(4,5-二甲基噻唑-2)-2,5-二苯基四氮唑溴盐]蛋白染色法对所合成的目标化合物进行了体外抗肿瘤细胞生物活性测试,发现化合物6,10和11对肝癌细胞(SMMC-7721)、乳腺癌细胞(MCF-7)和结肠癌细胞(SW480)有一定的抑制活性.     

番红花化学成分研究——Ⅲ.番红花花粉中的番红花新苷甲和乙的结构

从番红花(crocus sativus L.)花粉中分到两个新苷,命名为番红花新苷甲(1)和乙(2).经理化性质和对它们的 IR、UV、~1HNMR、~(13)C NMR 和 MS 数据的分析,鉴定1为异鼠李素-4′-O-α-L-鼠李吡喃糖(1→2)β-D-葡萄吡喃糖苷,2为β-对羟基苯基-乙醇-α-O-α-L-鼠李吡喃糖(1→2)-β-D 葡萄吡喃糖苷.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

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%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

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.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

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.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

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.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

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.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

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.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

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.