梨小食心虫性信息素的新法合成

梨小食心虫 (Grapholia molesta)是一种世界性果树害虫 ,主要危害梨、桃和苹果等果树 . 1 96 5年Geroge等 [1] 从该雌蛾腹部分离得到其性信息素 . 1 96 9年 Roelofs等 [2 ] 鉴定其结构为 8(Z/E) -十二碳烯 - 1 -醇乙酸酯 (6 ) .国内外对其生物活性进行了大面积田间试验 ,并用于     

茴香霉素族中两个新抗生素结构的确定

茴香霉素(Anisomycin,1)是一个抗滴虫属(Trichomonas),变形虫(Entamoeba)和真菌等作用很强的抗生素,用于防治植物真菌病害,其商品名为 Flagecidin.我们曾于1963年分离到此抗生素(508甲).Beereboom 等用化学方法确定了它的结构,但至今尚未见其类似物报道.1968年,Butler 又确定了它的构象.吴淑云等在筛选抗肿瘤的抗生     

酶促酮酸酯还原合成(S)-2乙酰氧基十三烷

Bartelt等 [1] 于 1 989年首次从穆勒果蝇 (Drosophila mulleric)的雄性成虫体内分离出其聚集信息素 ,并确证其主要生物活性的成分为 (S) -构型的 2 -乙酰氧基十三烷 (1 ) ,而 (R) -构型无生物活性 .1 999年Hillbur等 [2 ,3 ] 发现碗豆瘿蚊 (Contarinia pisi)的雌性性信息素主要成分中也含有 (1 ) ,其对碗豆瘿蚊雄虫具有很强的性引诱作用 .有关 (1 )的合成报道较多的为酶促反应合成法 [4～ 7] .我们曾以 1 -苯砜基 - 2 -丙酮为原料经酶促还原反应合成了目标产物 ,此法尽管合成路线短 ,光学产率较高 ,但反应原料不易购得 ,且使用两摩尔比…     

从中国南海软珊瑚中分离的环氧西松烯天然产物的结构更正

(- ) - 7,8- Epoxycembrene- C[( - ) - 7,8- ECC,1 ]是 Bowden等 [1] 于 1 980年首次从澳大利亚软珊瑚Sarcophyton crassocaule中分离得到的新的环氧西松烯 .其化学结构经光谱数据证实为 ( 1 E,3E,1 1 E) -1 -异丙基 - 4,8,1 2 -三甲基 - 7,8-环氧 - 1 ,3,1 1 -十四碳环三烯 ,但 C- 7,C- 8位环氧的立体化学未被确定 . Shin等 [2 ] 也从未鉴定属名的加勒比海域的软珊瑚 Eunicea sp.中分离得到过该天然产物 . 1 997年 ,饶志刚等 [3] 报道了从中国南海肉芝软珊瑚 ( Sarcophyton molle)中分离得到一环氧西松烯天然产物 ,确定其结构为天然…     

富勒烯配合物η2-C60[Ru(NO)(PPh3)]2的合成与表征

从1985年Kroto等[1]发现富勒烯至今, 其在化学、材料和物理等领域已有较多的研究[2～8]. 目前有关C60取代的金属小分子配合物(如羰基、亚硝酰基等)的研究方兴未艾. 而以NO为配体的亚硝酰基金属富勒烯配合物仅有数例[2,3], Green等[3]在研究以CO和NO为配体的金属富勒烯系列化合物的合成中, 认为C60不能与Ru(NO)2(PPh3)2发生反应. 本文利用Ru(NO)2(PPh3)2与C60反应首次合成出η2-C60[Ru(NO)(PPh3)]2配合物, 并对其进行了表征.     

《科学出版社》化学类最新书目摘要(2)

书 名 著者 年份 定价(元) 生物化学制备技术 苏拔贤 lops年 33 00 精编分子生物学实验指南 奥斯伯1998年11000 eR技术实验指南 迪芬巴赫1999年98.00 基因工程原理(上)(第二版)吴乃虎1998年38.80 电泳 何忠效等1999年48.00 蛋白质化学研究技术与进展 夏其昌1999年28.00 微生物学精要速览(影印版)JNickolin等1999年4500 遗传学精要速览(影印版)卜.C.Winter等1999年45.00 生物化学精要速览(影印版)B.DHames等1999年4800 动物生物学精要速览(影印版)oChwh D.Juld 1999年 38 00 生态学精要速览(影印版)Aulay M。he’lzlce等 1999年 43.00 …     

3-甲氧亚甲四氢噻吩的合成及其反应性能的研究

1967年Stoll,M.等人从咖啡中分离出一种具有强烈器官感受性质(Organolepticproperty)的物质。Bucchi,等人最后确定其化学结构为2-甲基-3-噁-8-硫代双环〔3,3,0〕-1,4二烯,俗称咖噁呋喃(Kahweo-furan〕(Ⅱ)。     

酶促还原法合成(S)-Phoracantholide Ⅰ

1976年Brown小组[1]首次从按树天牛后胸腺体中分离得到其防御信息素,并鉴定其主要组分结构为9-癸内酯(又称Phoracantholide Ⅰ),1983年Mori小组[2]成功合成出Phoracantholide Ⅰ的两种对映异构体,并经过手性固定相气相色谱确定出天然Phoracantholide Ⅰ的构型应为R构型.其后有关Phoracantholide Ⅰ的手性合成屡见不鲜,其主要合成方法为:不对称反应法[3～5]、酯促还原法[6,7]等,这些方法各有特色.由其逆合成可知,此类化合物可由羟基羧酸内酯化合成得到,故本文用1-苯磺酰基丙酮为原料经两步合成出9-羟基癸酸,然后借鉴Naoshima等的工作经海藻酸钙固定化的面包酵母(Saccharomyces Cerevisiae)进行酶促还原引入手性中心,进而经内酯化反应合成出目标产物(S)-Phora-cantholide Ⅰ.合成路线如下:     

新金刚石电子结构的第一性原理研究

金刚石、 石墨和卡宾碳是三种常见的碳同素异构体, 其外层轨道价电子分别是以sp³-, sp²-和sp¹-形式杂化而成的^［1］. 1991年, Hirai等^［2］在研究金刚石的形成机理时, 发现了一种新的碳同素异构体, 并将其命名为新金刚石(new diamond) ^{［3, 4］}. 在许多实验过程中虽然也曾获得过新金刚石^［5~11］, 但是这些实验获得的新金刚石的样品产量都较少, 且新金刚石的颗粒尺寸都很小(小于100 nm), 因此只能采用电子衍射(ED)的方法研究其结构. Jarkov等^［9］在分析多晶体ED图谱的基础上, 认为新金刚石是面心立方结构(FCC), 其晶格常数为0.357 nm. 2001年, Konyashin等^［1］通过ED图谱、电子能量损失谱和半经验的能量计算认定新金刚石为FCC的纯碳, 其晶格常数为0.356 3 nm. 我们曾用强磁场碳黑催化法制备出大量的新金刚石^{［3,4,12~14］}, 并对新金刚石的热稳定性进行了研究^［12］, 而对其结构和性能的研究尚未见报道.     

乌骨鸡黑素的元素组成与自由基状态初探

乌骨鸡(Gallina lanigera),又名白绒毛鸡,为我国特产的药用鸡种.远在唐代即知乌骨鸡能治风湿等病,明代李时珍在《本草纲目》中亦记载其药效.乌骨鸡的皮肤、肌肉、骨膜及内脏(除心、肝及肺外)中含有大量黑素,但其化学性质迄未鉴定.我们推测可利用黑素的自由基状态来探索黑素的理化性质及其与结构和功能的关系.Commoner 等于1954年最先发现在含黑素的组织(蛙卵)中自由基含量很     

异三尖杉酯碱类似物-酒石酸甲酯三尖杉碱酯的合成

异三尖杉酯碱系三尖杉属植物中所含具有抗肿瘤活性的四种生物碱之一,其本身的合成已有三种不同的方法^[1-3]先后获得成功。但是,在这些合成中,生成的异三尖杉酯碱都是立体异构体的混合物。据报导^[4.5]异三尖杉酯碱及其某些类似物对癌细胞具有明显的抑制作用。为了考察这类化合物的结构与抗癌活性之间的关系,并为异三尖杉酯碱立体异构体构型的确定提供依据,我们进行了(2R,3R)-酒石酸甲酯三尖杉碱酯Ⅵ和(2S,3S)-酒石酸甲酯三尖杉碱酯Ⅶ的合成。     

多碳醇类化合物的合成

本文由正-二十四烷酸与五氯化磷反应,得到的二十四烷酰氯在氯仿中和三乙胺存在下与1-吗啉-1-环己烯反应所得中间体,经酸性水解,碱性开环和酸化,得到7-氧代-三十烷酸,而据文献报导[7],正-二十四烷酞氯与1-吗啉-1-环己烯反应结果,得到的仍然是原料二十四烷酸。作者采用上述方法合成了五种新的7-氧代烷酸R-C(=O)-(CH²)⁵-COOH(R=n-C₁₄H₂₉,n-C₁₆H₃₃,n-C₁₈H₃₇,n-C₂₁H₄₃和n-C₂₃H₄₇)。所制得的7-氧代三十烷酸经黄鸣龙改良的开息纳尔-武尔夫还原,再经四氢锂铝还原,即得三十烷醇。     

Highly stereoselective reduction of methyl ketone complexes of the chiral Lewis acid [(η-C5H5)Re(NO)(PPh3)] by K(s-C4H9)3BH; synthesis of optically active secondary alcohols and derivatives

Reaction of optically active ketone complexes (+)-(R)-[(η⁵-C₅H₅)Re(NO)-(PPh₃)(η¹-O=C(R)(CH₃)]⁺ BF₄⁻ (R = CH₂CH₃, CH(CH₃)₂m C(CH₃)₃, C₆H₅) with K(s-C₄H₉)₃BH gives alkoxide complexes (+)-(RS)-(η⁵-C₅H₅)Re(NO)(PPh₃)-(OCH(R)CH₃) (73–90%) in 80–98% de. The alkoxide ligand is then converted to Mosher esters (93–99%) of 79–98% de.     

New heterometallic copper zinc alkoxides: synthesis, structure properties and pyrolysis to Cu/ZnO composites

The copper compound [(THF)KCu(O^tBu)₃]_∞ 1 was obtained by interaction of a 1:1 mixture of ZnCl₂/CuCl₂ with KO^tBu. Bi- and trifunctional aminoalcohols were used to synthesize the intramolecularly donor stabilized Cu(II) alkoxides Cu(OCH(R)CH₂NMe₂)₂ (3: R=Me, 4: =CH₂NMe₂) where 4 was structurally characterized. Lewis acid–base adduct formation with (Me₃Si)₃CZnCl gave the heterodinuclear compounds (Me₃Si)₃CZnCl · Cu(OCH(R)CH₂NMe₂)₂ (5: R=Me, 6: R=CH₂NMe₂), which were characterized by X-ray single-crystal structure analysis. The two metal centers Cu and Zn of 5 and 6 are bridged by two oxygen atoms to form a Cu–O–Zn core. Pyrolysis of compounds 5 and 6 in dry argon or a H₂/N₂ mixture at atmospheric pressure forms metallic copper and zinc oxide, whereas pyrolysis under O₂/Ar forms additionally oxidized copper species. Elemental analysis of the pyrolysis products showed carbon and nitrogen contamination. Scanning electron microscopy and energy dispersive X-ray analysis were performed to get information on the morphology and the chemical composition of the pyrolysis products.     

Allylstannation V. cis-stereoconvergent sysnthesis of homoallylic alcohols and 4-chloro-2,6-dialkyl-3-methyltetrahydro-pyrans by the addition reaction of 1-buten-3-yldichloro-n-butyltin and aldehydes

1-Buten-3-yl-n-butyldichlorotin, generated in situ by redistribution of (E/Z)-2-butenyltri-n-butyltin and BuSnCl₃, reacts readily with neat RCHO (R = CH₃, C₂H₅, (CH₃)₂CH) at 25°C to give linear alcohols RCH(OH)CH₂CH---CHCH₃ and/or 2,3,4,6-tetrasubstituted tetrahydropyrans, CH₂CH(R)OCH(R)CH(CH₃)CH-(Cl), which are mainly in the cis-configuration with respect to the CH(CH₃)-CH(Cl) bond. When R = (CH₃)₃C and C₆H₅, only the homoallylic alcohols are obtained. These cis-stereoconvergent syntheses are explained in terms of kinetic control of the formation of adducts obtained by insertion of one or two aldehyde molecules into the organotin substrate.     

Exchange reactions of distibines

Distibines of the type R₂SbSbR′₂ with R = CH₃, R′ = C₂H₅ (1), R = CH₃, R′= n-C₃H₇ (2), R = CH₃, R′= C₆H₅ (3), R = C₂H₅, R′= C₆H₅ (4), R = n-C₃H₇, R′ = C₆H₅ (5), and R = CH₃, R′ = 2,4,6-(CH₃)₂C₆H₂ (6) are formed in equilibria by exchange reactions of the respective distibines of the type R₄Sb₂ and R′₄Sb₂.     

Distinguishing conventional and distonic radical cations by using dimethyl diselenide

Dimethyl diselenide is demonstrated to be among the most powerful reagents used to identify distonic radical cations. Most such ions readily abstract CH₃Se^. from dimethyl diselenide. The reaction is faster and more exclusive than CH₃S^. abstraction from dimethyl disulfide, a reaction used successfully in the past to identify numerous distonic ions. Very acidic distonic ions, such as HC⁺(OH)OCH^.₂, do not undergo CH₃Se^. abstraction, but instead protonate dimethyl diselenide. In sharp contrast to the reactivity of distonic ions, most conventional radical cations were found either to react by exclusive electron transfer or to be unreactive toward dimethyl diselenide. Hence, this reagent allows distinction of distonic and conventional isomers, which was demonstrated directly by examining two such isomer pairs. To be able to predict whether electron transfer is exothermic (and hence likely to occur), the ionization energy of dimethyl diselenide was determined by bracketing experiments. The low value obtained (7.9 ± 0.1 eV) indicates that dimethyl diselenide will react with many conventional carbon-, sulfur-, and oxygen-containing radical cations by electron transfer. Nitrogen-containing conventional radical cations were found either to react with dimethyl diselenide by electron transfer or to be unreactive.     

Synthesis and Characterization of Dinuclear Aluminum Complexes Bearing N,N-Dialkylaniline-amido Ligands and Its Catalytic Properties for Lactone Polymerization

Two ligands [ortho-C6H4NR2（CH2NH）]2CH2CH2（3： R=Me; 4： R=EO were prepared by the reduction of preligands [ortho-C6H4NR2（CH=N）]zCH2CH2（1： R=Me; 2： R=Et）. These ligands reacted with AIMe3 to afford the corresponding dinuclear aluminum complexes {A1Me2[ortho-C6H4NR2（CH2N）]}2CHzCH2（5： R=Me; 6： R=Et）. All the compounds were characterized by 1H and UC nuclear magnetic resonance（NMR） spectroscopies and elemental analyses. The catalytic properties of the aluminum complexes towards the ring-opening polymerization of lactones were investi- gated in the presence of benzvl alcohol. All the oolvmerization reactions were proceeded in a controlled manner.     

Synthesis and properties of alkyldicyclopentadienyl-vanadium(III) compounds

The compounds Cp₂VR (R = CH₃, C₂H₅, n-C₃H₇, n-C₄H₉, n-C₅H₁₁, CH₂C(CH₃)₃ or CH₂Si(CH₃)₃) have been prepared from Cp₂ VCl and RMgX in n-pentane. The air-sensitive compounds are stable at room temperature, but decompose between 65 and 138°C. The thermal stability decreases in the order R = CH₃ CH₂Si(CH₃)₃ > C₂H₅ > CH₂C(CH₃)₃ > n-C₅H₁₁ > n-C₄H₉ > n-C₃H₇. Compounds with R = i-C₃H₇ or t-C₄H₉ could not be obtained.     

硼化合物研究(Ⅲ)——B10H102-、B12H122-以及B3H8-阴离子的二茂铁季铵盐的合成

本文通过B_nH_n^2-(n=10,12)及B₃H₈^-盐分别与C₅H₅FeC₅H₄CH₂N(R)Me₂Cl和Fe(C₅H₄CH₂N(R)Me₂Cl)₂(R=CH₃-,C₂H₅-,n-C₃H₇-,CH₂=CH-CH₂-和CH≡C-CH₂-)在水溶液中进行反应,合成了相应的三十个新的硼烷阴离子衍生物,这些化合物对水稳定性好,B₁₀H₁₀^2-及B₁₂H₁₂^2-衍生物对热、酸、碱和氧化剂均很稳定。研究了反应物之间的用量比例对反应产物的影响。实验结果表明,不论反应物之间的克分子比如何变化,只能得到相应的一种产物(产率90-98％)。