脱氧莪术二酮的合成

( )-莪术二酮(1)是从中药中分离出并具有明显抗癌活性的十员环倍半萜。最近,我们简要报道了(-)-莪术二酮的全合成。在全合成探索中,为了试验以 Oxy—Cope 重排反应     

多羟基取代二氢沉香呋喃倍半萜的合成方法

二氢沉香呋喃倍半萜是一类具有杀虫、抑菌等多种活性的天然化合物.由于重要的生物活性和结构的复杂性,从而吸引了有机合成化学家的关注.最近,我们小组从桉烷倍半萜α-(-)-山道年出发,经过NBS促进的四氢呋喃环成环、OsO4双羟基化、环氧化合物的碱重排等一系列官能团转化,合成了七羟基取代的二氢沉香呋喃倍半萜化合物1,进而开拓了一种新颖、简洁的合成多羟基取代二氢沉香呋喃倍半萜的方法,其合成路线如下所示.     

内分子DIELS-ALDER反应合成DRIMANE类倍半萜化合物DRIMENIN, POLYGODIAL及CINNAMOLIDE的全合成

近年来有不少报道从事于生理活性Drimane类倍半萜的合成,较多采用了分子间Diels-Alder反应来建立Drimane的骨架。本文首次采用内分子Diels-Alder反应作为关键反应合成了Drimane类化合物。同时还在引入了手性诱导基团后,首次完成了从无手性的原料化合物β-紫罗兰酮至光学活性(-)-drimenin1的不对称合成。     

矢车菊中倍半萜 - 4,9-二氧-红没药-2,7(14), 10-三烯及其类似物的合成

红没药烯及其含氧化合物是自然界中存在的一类单环倍半萜,它是利用单萜合成倍半萜的实例。1986年Jakupovic等报道从植物矢车菊中提取出新的倍半萜——4,9-二氧-红没药-2,7(14),10-三烯及它的异构化产物4,9-二氧-红没药-2,7 E,10-三烯。我们以(-)-香芹酮(1 a)和( )-二氢香芹酮(1b)作原料合成了4,9-二氧-红没药-2,7(14),10-三烯(4 a),它的二氢类似物4,9-二氧-红没药-7(14),10-二烯(4b)和4,9-二氧-     

3,4-二芳基吡咯酮衍生物的合成和生物活性

考布他汀-A4(Combretastatins-A4,CA-4)是从天然产物中分离得到的抗癌活性化合物,其分子中Z-构型烯键易异构化转变为无抗癌活性的E-构型.以吡咯-2,5-二酮或吡咯-2-酮代替烯键,设计合成了4个新的CA-4类似物.它们的合成是以3,4-二甲氧基苯乙酮或3-氟-4-甲氧基苯乙酮为起始原料,经α-溴化、改良的Gabriel合成法、与3,4,5-三甲氧基苯乙酸缩合、环化-氧化或环化四步反应完成.其结构用1H NMR,13C NMR,ESI-MS及元素分析进行了表征.用MTT法测试了CA-4类似物对人白血病细胞HL-60、肝癌细胞SMMC-7721和肺腺癌细胞A549的体外抗肿瘤活性.初步结果表明,含氟化合物3,4-二芳基-2,5-吡咯酮(1b)的抗肿瘤活性接近CA-4,IC50值达到0.03～0.05μmol·L-1.     

室温条件下硝酸铋高效催化“一锅法”合成4(3H)-喹唑啉酮衍生物

<正>4(3H)-喹唑啉酮及其衍生物具有抗疟疾、抗癌、抗痉挛、消炎、抗菌等多种生理活性[1-5]。因此,该类化合物的合成引起了人们极大的兴趣。1895年,Niementowski[6]发明了一种简单且易操作的合成4(3H)-喹唑啉酮的方法,该方法在1946年     

7-O-羧烷基化白杨素衍生物的合成及其抗癌活性

以白杨素(1)为起始原料,与溴代羧酸乙酯经取代反应制得中间体7-O-乙氧羰基烷基白杨素(3a~3d);3a~3d经水解反应合成了7-O-羧烷基化的白杨素衍生物(4a~4d),其中4b~4d为新化合物,其结构经1H NMR,13C NMR,IR和ESI-MS表征。初步的体外抗癌活性实验结果表明,3和4对人肝癌细胞Hep G2和人胃癌细胞MGC-803具有一定的抗癌活性,且大多数化合物的抗癌活性比母体化合物1强,其中6-(5-羟基-2-苯基-4H-苯并吡喃酮-7-氧)己酸(4d,IC504.04μmol·L-1)对MGC-803细胞的活性抑制作用强于阳性药物DDP(IC504.40μmol·L-1)。     

三苯基锗不饱和烃基酸衍生物的合成和性质

随着倍半锗氧类化合物的合成及应用研究的日益广泛 ,含 Ge_ O键的烃基锗衍生物的合成及应用也逐渐引起了人们的关注 .1 984年 ,L ukevics等 [1]合成了具有抗癌活性的介吗川类化合物 ,1 990年Kakimoto等 [2 ] 报道了具有杀菌活性的环状烃基羧酸的合成与应用 .但是三烃基锗的膦酸类衍生物的合成及生物活性研究均未见文献报道 .为了研究该类化合物的生理活性 [3～ 5] ,本文以三苯基氯化锗和炔基 (烯基 )膦酸钠为原料 ,在苯中反应 ,合成了一系列双 - O- (三苯基锗 )炔基 (烯基 )膦酸酯和单 - O-三苯基锗炔基 (烯基 )膦酸 ,部分化合物初步生理…     

(一)-△~(9(12))-CapneUene类的合成中间体——光学活性5-甲基-8-羟基双环[3,3,0]2一辛酮的不对称合成研究

通过手性硝基烯胺(4)与α-甲基-δ-戊内酯烯醇锌盐发生加成消除反应解决了倍半萜Capnellene类合成中构筑不对称季碳这个难题,对映体过量(e. e. )为94％。由L-脯氨酸经14步实现了(一)-△~(9(12))-Capnellene类的合成中间体——光学活性5-甲基-8-羟基双环[3 3,0]-2-辛酮(13)的对映选择合成。     

水合三环己基锡4-吡啶甲酸酯配合物的合成、结构及抗癌活性

三环己基氢氧化锡与4-吡啶甲酸按物质的量比1∶1在乙醇溶剂中反应,合成了水合三环己基锡4-吡啶甲酸酯配合物。采用元素分析、红外光谱、核磁共振、差热分析和X-射线单晶衍射等对配合物进行了结构表征,并对配合物进行量子化学计算和体外抗癌活性研究。结果表明：配合物中心锡原子为五配位畸变三角双锥构型;配合物对人肝癌细胞(HUH7)、人肺腺癌细胞(A549)、人表皮癌细胞(A431)和人结肠癌细胞(HCT-116)的抑制活性高于顺铂。     

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.     

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.     

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.     

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.     

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.