风毛菊化学成分研究（Ⅰ）

从风毛菊中分离得到16种化合物,经光谱方法鉴定为山奈素-3-O-(6＂-O-巴豆酰)-β-D-葡萄糖甙(1)、槲皮素-3-O-(6＂-O-巴豆酰)-β-D-葡萄糖甙(2)、丁香甙甲醚(3))、山奈素-3-O-β-D-葡萄糖甙、槲皮素-3-O-β-D-葡萄糖甙、丁香甙、α-香树脂醇棕榈酸酯、β-香树酯醇棕榈酸酯、羽扇豆醇棕榈酸酯、羽扇豆醇乙酸酯、羽扇豆醇、β-谷甾醇、棕榈酸、二十四烷酸、二十六烷酸、二十五烷烃,其中(1)、(2)和(3)为新化合物。     

宽叶秦岭藤根部的化学成分

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).     

树萝卜属植物化学成分的研究（Ⅱ）：红花树萝卜化学成分的研究

从云南省西双版纳地区产红花树萝卜中分离得到7种化合物,经光谱分析及衍生物的制备等确定为:熊果-12-烯-2β羟基-28-酸(Ⅰ),6β-羟基熊果酸(Ⅱ),羊齿烯醇(Ⅲ),木栓醇(Ⅳ),β-谷甾醇(Ⅴ),胡萝卜甙(Ⅵ),β-谷甾醇葡萄糖醛酸甙(Ⅶ),其中化合物(Ⅰ)是未见报道的新化合物。     

厚皮树树皮的化学成分研究

采用各种柱色谱法从厚皮树(Lannea coromandelica)树皮的78%乙醇提取物中分离得到9个化合物。通过理化性质和波谱数据鉴定为:槲皮素-3-O-芸香糖苷(1),豆甾-4-烯-6β-醇-3-酮(2),蒲公英赛酮(3),蒲公英赛醇(4),乙酰蒲公英赛醇(5),5α-豆甾烷-3,6-二酮(6),β-谷甾醇(7),β-胡萝卜苷(8),香草醛(9)。除了化合物(7),其他化合物都是从该植物中首次分离得到。     

仿刺参中两种新海参烷型皂苷

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...     

万年蒿中二萜类化合物的结构研究

自菊科蒿属植物万年蒿(Artemisia Sacrorum Ledeb)地上部分首次分得三个贝壳杉烷型(Kauranetape)二萜类化合物,经理化常数测定及光谱分析(IR,’H-NMR,~(13)C-NMR,MS,二维核磁共振光谱)鉴定其结构分别为:3α,16α,17-三羟基贝壳杉烷[I],3α,16α-二羟基贝壳杉烷-17-0-β-D-葡萄糖甙[Ⅱ]和16α-羟基贝壳杉-3-酮-17-0-β-D-葡萄糖甙[Ⅲ]。其中[Ⅰ]为一新天然产物,[Ⅱ]为一未见报道的新化合物。通过对该三个化合物的~(13)C-NMR光谱分析,讨论了不同位置取代基对其~(13)C-NMR光谱化学位移的影响。     

豆荚软珊瑚Lobophytum sp. 的次生代谢产物研究

从海南岛三亚海域采集的软珊瑚Labophytumsp.中分离得五个甾醇苷(1)～(5)。通过波谱分析，确定它们的化学结构依次为3'-O-乙酰基-4-O-[β-D-吡喃木糖苷]-孕甾-20-烯-3β,4α-二醇(1)，4-O-[β-D-吡喃木糖苷]-孕甾-20-烯-3β,4α-二醇(2),4'-O-乙酰基-4-O-[β-D-吡喃木糖苷]-孕甾-20-烯-3β,4α-二醇(3),4'-O-乙酰基-4-O-[β-D-吡喃阿拉伯糖苷]-孕甾-20-烯-3β,4α-二醇(4)和4-O-[β-D-吡喃阿拉伯糖苷]-孕甾-20-烯-3β,4α-二醇(5),其中1为新化合物。体外细胞毒性实验表明：化合物(1),(2)和(5)对SKMG-4,Hep-G2和CNE2三种人体癌细胞具有抑制作用。     

甾醇、甾烷醇柱前衍生高效液相荧光分析

采用荧光衍生化试剂2-(9-咔唑)乙酰氯,对天然产物谷甾醇、豆甾醇、菜油甾醇及谷甾烷醇的柱前衍生化条件,包括催化剂的种类、反应温度、衍生化时间等进行了考察,结果表明催化剂选用三乙胺,反应温度80℃,时间20 min,衍生产物具有恒定的最大检测响应值.利用高效液相色谱对衍生产物进行分析,并对衍生物的分离进行了优化选择,达到了较好的基线分离,检出限为12.6～29.5 nmol/L.方法应用于血清样品的测定,谷甾醇、豆甾醇、菜油甾醇和谷甾烷醇的标准加入回收率分别为101.9%、102.4%、101.0%和103.2%.     

内醚糖的研究Ⅳ.2,3-内醚-5-去羟-α-和β-D-来苏糖甲基甙

自2,3-内醚-α-和β-D-来苏糖甲基呋喃甙(Ⅳ,α和β)合成了2,3-内醚5-去羟-α-和β-D-来苏糖甲基甙(Ⅶ,α和β).合成的步骤为:2,3-内醚-α-和β-D-来苏糖甲基呋喃甙(Ⅳ,α和β)→2,3-内醚-5-O-对甲苯矿酰基-α-和β-D-来苏糖甲基呋喃甙(V,α和β)→2,3-内醚-5-碘代-5-去羟-α-和β-D-来苏糖甲基甙(Ⅵ,α和β)→2,3-内醚-5-去羟-α-和β-D-来苏糖甲基甙(Ⅶ,α和β).除了最后一对外,其余的中间物都是结晶的. 本工作得到了结晶的2-O-对甲苯矿酰基-3,5-异丙亚基-α-和β-D-木糖甲基呋喃甙(Ⅱ,α和β).水解后,α-端基差向异构体生成美丽的2-O-对甲苯矿酰基-α-D-木糖甲基呋喃甙(Ⅲα,R=Ts)晶体,可是在同样的处理下,β-端基差向异构体却只是糖浆状产物(Ⅲβ,R=Ts).     

土槿皮三萜成分的研究

从土槿皮(Pseudolarix kaempferi, Gord.)中分到两个三萜成分, 经化学和光谱方法证明, 其一为具有羊毛甾烷母核的新三萜-3氧代-羊毛甾-7,23,25-三烯-23,26-环氧-27-羧酸, 命名为金钱松呋喃酸(1), 另一个为白桦脂酸(2), 此外, 还分到β-谷甾醇和β-谷甾醇-β-D-葡萄糖苷。     

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%.     

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.     

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.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

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.