中国南海软珊瑚Nephthea Sinulata中的一个新甾醇

海洋软珊瑚中多羟基甾醇已有不少报道.本文报道从我国西沙群岛采集的软珊瑚Nephthea sinulata的乙醇抽提物中分离到的一个新甾醇1的结构鉴定. 1由质谱和元素分析确定其分子式为C_(30)H_(48)O_4,400MHz ~1H NMR示有末端双键(4.63、4.69ppm各一个质子,宽单峰),1个三取代的双键(5.55ppm,1H,d,J=2Hz).δ0.73ppm处单峰(3个质子)归于C-18角甲基,甾醇中常见的C-19角甲基信号δ1.00～1.10(3H,s)消失,代替出现的是一个2组二重峰(3.63、3.66ppm,2H,ABq,J=12Hz).这归属于C-     

中国软珊瑚化学成分的研究 12.一种新颖独特的四萜酯——扭曲肉芝甲酯的结构测定

从南海扭曲肉芝软珊瑚(Sarcophyton tortuosum Tixier-Durivault)中分离得一种结构新颖的四萜酯——扭曲肉芝甲酯(methyl sartortuoato,1)。1是无色结晶,含一分子结晶乙醇。经脱去结晶醇后,m.p.246～246.5℃,[α]_D~(28) 195.8°(c 0.0475,C_2H_5OH),分子式为C_(41)H_(62)O_8,m/z:682,4469(M~ )。 1 具有以下的结构:一个羧酸甲酯,ν_(max):1745,1220cm~(-1),δ_H3.58(3H,s,41-H),δ_C174.5(s,20-C)ppm。三个羰基,ν_(max):1725,1700cm~(-1),δ_C 213.13(s),213.30(s),     

沙打旺中两种新三萜化合物

沙打旺(Astragalus Adsurgens Pall)是豆科黄芪属植物,我们对其化学成分和毒性成分进行了研究,从中分出2个新的四环三萜类化合物9和10.本文报道它们的分离鉴定工作。 1 新化合物的特征 化合物9:白色粉末,m.p.249～251℃,[a]_D~(20):—47.06°(C 0.34,CHCl_3),HRMS(M~+)m/z:486.3345,结合元素分析,分子式定为C_(30)H_(46)O_5.IR(cm~(-1))示有3367～3567(—OH),1724,1740(C—O,五元环);~1H NMR(δppm,CDCl_3,TMS),1.07～1.37处有7个—CH_3,0.44(1H,d,J=4.49 Hz),0.65(1H,d,J=4.48 Hz)AB型偶合系统和IR 3050cm~(-1),提示分     

新香茶菜素的结构

从河南大别山地区产显脉叶香茶菜[Rabdosia nervosa(Hemsl.)C.Y.Wu et H.W.Li]叶的乙醚提取物中分离到三个二萜化合物,其中 odonicin 和显脉香茶菜素(nervosin)已报道,本文报道另一个新化合物,命名为新香茶菜素(neorabdosin,1)的结构研究.1为无色针状结晶,有微弱芳香气味,熔点230～232℃,[α]_D~(13)-175.5°(c 0.86,吡啶).经元素分析和质谱测定,其分子式为 C_(24)H_(30)O_7,M_r=430.48.IR:1735,1220(乙酰基),1720(六     

Five New Glycosides, Ligurobustosides E, F, I, J and K from Ligustrum Robustum

InourPredousPaper,wemprtedfournewmOnot~dglycosidesA-D[l1.hahrinVestigationonthesamplanledtotheisolationandidenndcationofcomPOundsl-5.LigUrdbustsideE(l),[a];:=67.2"(c=O.O30,Me0H)wasbbtainedaswhieamorPhOUSpower.Themoledformula(C3l&4Q2)oflwasconfiImdbythePOhavionFAB-MS~(63lIM+Na]+).The1HNMReqatthearondcregionshOWedanA:BzSyStembelongingtoap-COUmarOylmoietyl56.80(2K4J=8.4Hz),57.45(2H,4J=8.4th)].TwoolefinicprotonsignalswhichapPearedasanABgheml56.34(lKd,J=l5.9Hz),7.63(1Rd,J=l5…     

南瓜子化学成分的研究——Ⅰ.新氨基酸:南瓜子氨酸的分离及其结构的研究

1.从治疗血吸虫病中药中国南瓜子(Cucurbita moschata Duch.),经化学提取得一种新化合物,其物理及化学性质与已知的氨基酸均不一致,暂取名为南瓜子氨酸(cucurbitine),简称南氨酸。 2.南氦酸经元素分析及分子量测定结果,确定其分子式为C_5H_(10)O_2N_2。熔点约260°(分解)。[a]~(27)_D=-19.76°(c=9.31％;水)。并制成其盐酸盐,熔点278°(分解),[a]~(19.3)_D=-15°(c=1％;水);高氯酸盐,熔点约275°(分解),[a]~(20.5)_D=-13.08(c==10.4％;水);二苯甲酰衍生物,熔点207—208°(分解),[a]~(24.5)_D=-1.63°(c=4.83％,甲醇);双二硝基苯衍生物,熔点230—232°(分解)。 3.南氢酸经红外吸收光谱分析及功能团的测定,证明其中含有二氨基,伯胺和仲胺各一。另一功能团是羧基,因此其示性式应为C_4H_6(NH)(NH_2)COOH。 4.南氨酸的二硝基苯衍生物的紫外吸收光帮特征及酸水解稳定性试验结果表示其母核与氮戊环相近。 5.将南氨酸直接用高锰酸钾氧化所得产物证明是β-丙氨酸与甘氨酸。这表明其氨某与羧基的位置只有在3,4-位或3,3-位的可能,即Ⅱ或Ⅲ的结构式。该二化合物后经人工合成,与天然南氨酸进行混合熔点测定,颜色反应,氧化反应,纸上层析,红外吸收光谱及生物试验等比较结果,证明与Ⅲ完全一致。即南氨酸的化学结构是(一)-3-羧基-3-氨基氮戊环,是一新发现的氨基酸。     

Lanthanide-catalyzed cyclocarbonylation and cyclothiocarbonylation: a facile synthesis of benzannulated 1,3-diheteroatom five- and six-membered heterocycles

<正>NMR spectra were recorded in CDCl3 or DMSO-d6 on a Bruker Avance 400 operating at 400 MHz with TMS as internal standard. 1H-benzo[d]imidazol-2(3H)-one(3aa) [1]: 1H NMR(400 MHz, DMSO-d6) δ 10.5(s, 2 H, NH), 6.90(s, 4H)(aromatic CH). 13 C NMR(400 MHz, DMSO-d6) δ 155.7, 130.1, 120.9, 108.9. NH HN O3 aa 1-(2-Aminophenyl)-3-phenylurea(3aa′) [2]: 1H NMR(400 MHz, DMSO-d6) δ 8.75(s, 1H), 7.71(s, 1H)(CONH), 7.44(d, J = 8.0 Hz, 2H), 7.33(d, J = 7.8 Hz, 1H), 7.26(t, J = 7.7 Hz, 2H), 6.94(t, J = 7.4 Hz, 1H), 6.84(t, J = 7.4 Hz, 1H), 6.74(d, J = 7.8 Hz, 1H), 6.57(t, J = 7.4 Hz, 1H)(aromatic CH), 4.78(s, 2H)(NH2). 13 C NMR(400 MHz, DMSO-d6) δ 153.6, 141.4, 140.6, 129.2, 125.2, 124.8, 124.2,121.9, 118.4, 117.3, 116.4.     

中药黄藤化学成分的研究

从黄藤(Fibraurea tinctoria Lour.)中,除主要成分非洲防已碱外,还获得四种结晶物质,其中两种新植物碱,一是水溶性植物碱,暂名为黄藤素甲,其分子式为C_(25)H_(29)O_7N,制得其结晶的盐酸盐C_(25)H_(29)O_7N·HCl·H_2O,熔点196—198°,[α]_d~(15)= 273.3(1％酒精溶液),及氢碘酸盐(C_(25)H_(29)O_7N·HI),熔点217—218°。黄藤素甲经还原后,得一无色晶体,熔点184—186°。另一种植物碱暂名为黄藤素乙,其分子式为C_(18)H_(19)O_8N,熔点192—193°,[α]_D~(15)= 28.33(1％氯仿溶液)。其结晶的氢溴酸盐(C_(18)H_(19)O_8N·HBr)熔点202—203°。其他两种中性物中,有一种是内酯,暂称为黄藤内酯,其分子式为C_(27)H_(28)O_9,熔点278°,[α]_D~(15)= 36.60(1％酒精溶液),其肟衍生物,C_(27)H_(28)O_8NOH,熔点254—256°。另一中性物为固醇,其分子式为C_(27)H_(45)OH,熔点136—137°,[α]_D~(18)= 24.51(1％氯仿溶液),其乙酰基化合物C_(27)H_(45)O(CH_3CO),熔点127—128°,苯甲酰基化合物C_(27)H_(45)O(C_6H_5CO),熔点139—140°,洋地黄皂甙化合物,熔点226—228°。     

鸦胆子化学成分的研究 Ⅱ.鸦胆子苦素E-葡萄糖苷

从中药鸦胆子中分得一新的苦素配糖体,C_(26)H_(38)O_(14)(M~ 574),m.p.243～245℃,[α]_D~(23)60.0°(c.1.70,H_2O),经苦杏仁酶水解及光谱法推定其结构为鸦胆子苦素E的2-β-D-葡萄糖苷。     

中国乌头之研究 V.雪上一枝篙中的生物碱

从云南省东川县产的雪上一枝篙(Aconitum bullatifolium Lévl.var.homotrichum WT.Wang)中共分得四种生物碱. 一枝篙甲素定为C_(21)H_(31)O_2N[熔点251-253°,[α]_D~(27)=-56°(c 0.4,甲醇)],是一不饱和的叔胺碱,含二个羟基和一个氮乙烷基.一枝篙乙素定为C_(24)H_(39)O_6N[熔点158-159°,[α]_D~(21)= 21.82°(c 1.65,甲醇)],含羟基、甲氧基各三及氮乙烷基一.一枝篙丙素为C_(26)H_(41)O_7N[熔点220°.硝酸盐熔点197-198°,[α]_D=-7°(c 7.18,水)],含二个羟基,三个甲氧基和一个氮乙烷基.经苛性钾水解后即获得一枝篙乙素和乙酸,故为一枝篙乙素的乙酸酯.一枝篙丁素为C_(23)H_(37)O_9N,熔点211°含三个甲氧基及一个氮甲烷基.上述四种新生物碱,其中三种的示性式可写为: 一枝篙甲素:C_(21)H_(31)O_2N=C_(19)H_(24)(OH)_2(N-C_2H_5)(F) 一枝篙乙素:C_(24)H_(39)O_6N=C_(19)H_(22)(OH)_3(OCH3)_3(N-C_2H_5) 一枝篙丙素:C_(26)H_(41)O_7N=C_(19)H_(22)(OH)_2(OCH_3)_3(CH_3COO)(N-C_2H_5)     

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.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

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.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

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.     

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.     

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.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

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.     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.