金属还原氢化反应的研究

本实验室曾已完成如下反应：并将所得LiH+NaCl用于合成氢化铝锂LiAlH_4获得成功。本文将上述反应推广于从碱土金属氯化物合成相应金属的氢化物:     

氢化锂铝(LiAlH_4)的合成

氢化锂铝是有机合成中的强烈还原剂,在无机合成方面,它是合成某些金属氢化物和复合金属氢化物的重要试剂,至于它在化学领域中的应用,在此不作介绍,而本文主要内容是报导本组实验室合成氢化锂铝的方法及原料氢化锂的制备与仪器装置,目的是为其它实验室合成氢化锂铝,以及在我国进行工业生产提供合适条件。合成LiAlH_4一般有二个方法: 1)借氢化锂与无水三氯化铝在无水乙醚中的反应;2)借氢化锂与无水三溴化铝在无水乙醚中的反     

接枝于聚薄荷基丙烯醇的手性氨基醇的合成及其对Henry反应的不对称催化作用的研究

一种新型的旋光活性的氨基醇类聚合物被合成出来。以旋光活性聚薄荷基乙烯基酮为原料, 将聚薄荷基乙烯基酮用氢化铝锂还原后得到聚薄荷基丙烯醇(poly-MPO),poly-MPO与氢化钠反应后与环氧氯丙烷反应得到固载环氧丙烷的poly-MPO。将固载环氧丙烷的poly-MPO与各种类型的胺反应得到接枝于聚薄荷基丙烯醇的手性氨基醇(poly-MPO)-APO。将其应用在催化不对称Henry反应中得到了高产率、中等选择性的产物。     

二元氯化物熔体中锂和钠离子析出电位的测定及去极化作用的研 究

本文利用I-V曲线法测定了锂和钠离子在二元混合氯化物体系(LiCl-KCl;NaCl-KCl)中的析出电位,为利用熔盐电解法制备低钠高纯铝-锂合金提供了理论依据。根据锂离子在铝阴极上产生的去极化值求出铝和锂发生合金化反应的热力学意义,提出二元合金类型与极化类型之间的经验关系。首次通过研究锂离子在铝合金电极上的去极化行为,发现某些第三合金元素的存在可以加强锂离子的去极化作用,为进一步制取低钠高纯三元铝-锂-M合金系列提供了参考。还研究了在氯化钾-氯化锂体系中,氯化锂浓度对锂离子在铝阴极上析出电位的影响,求出了氯化锂的平均活度系数。     

季铵化聚丙烯腈的制备及其催化制备生物柴油

以聚丙烯腈纤维(PAN)为原料,氢化铝锂为还原剂,先将PAN上的腈基还原为伯胺基团得到还原产物PAN-NH2(APAN),再与具有季铵结构的2,3-环氧丙基三甲基氯化铵(EPTAC)键合,制备出季铵键合PAN聚合物;最后通过氢氧化钠活化得到具有强碱性季铵基团的聚合物PAN-N+(CH3)3OH-(QPAN).考察了氢化铝锂、EPTAC加入量及反应时间、温度等因素对季铵基键合量(—N+(CH3)2Cl-含量)的影响规律,采用X-射线光电子能谱(XPS)、红外光谱(FTIR)、示差扫描量热仪(DSC)等对聚合物结构和性能进行表征.结果表明,当PAN与还原剂氢化铝锂摩尔比为1∶3,温度为80℃,反应时间为24 h时,伯胺基团含量可达到0.4812mmol/g.进一步用还原产物APAN与EPTAC以最优反应条件(摩尔比1∶3,温度80℃,反应时间12 h)下进行反应,所得产物通过NaOH活化,得到碱强度为0.8034 mmol/g的QPAN.将QPAN用于大豆油和甲醇的酯交换反应制备生物柴油.在反应温度60℃,反应时间4 h,醇油摩尔比为16∶1,QPAN添加量为2.0 meq(OH-)的条件下,生物柴油产率可达64.7%.     

温和条件下氢化锂的催化合成

本文提出了一种温和条件下合成氢化锂的方法,催化剂是由萘或萘的甲基衍生物和TiCl4组成,具有很高的活性。它可以使金属锂在25-50℃常压加氢,根据催化剂的不同组成,锂可以在2～5小时内定量地转化成氢化锂,考察了催化剂的稳定性,并确定了催化剂组成和控制反应步骤之间的关系。     

氢化铝锂还原带有酯基的八氢吲(口乃木)并[2,3-α]喹嗪化合物的竞争加成反应

用氢化铝锂还原酯类化合物,得到的产物通常是醇。作者已报道:在吲哚生物碱合成中,为了制备醇Ⅱ,采用氢化铝锂还原酯Ⅰ的方法,得到了预期产物Ⅱ,另外,还得到另一个副产物Ⅲ,收率分别为30.8％和12.9％,两个产物的结构已通过光谱分析证明。     

化学反应的内禀反应坐标法——Ⅲ.乙炔与氢化锂二聚体加成反应的反应路径解析

本文利用量子化学从头计算法(内禀反应坐标法)在3-21G基组上对乙炔与氢化锂二聚体的加成反应作了反应路径解析。确定了过渡态的结构、反应势能曲线、活化能、反应热以及沿着IRC的一些物理量的变化。研究结果表明:在乙炔与氢化锂二聚体的加成反应途径上,靠近孤立反应物存在一个准稳定的分子复合物状态,并且这个分子复合物经单分子重排生成产物的基元过程构成了该反应的定速步骤。根据RRKM理论还估算出相应于单分子重排过程的频率因子和活化熵值。对反应过渡态的前线分子轨道分析表明:在过渡态的形成过程中,反应物系分子之间的HOMO-LUMO和HOMO-HOMO相互作用都起了重要作用。通过比较乙炔与氢化锂单体和二聚体两个加成反应的活化能、活化熵和反应频率因子,指出了这两个反应发生相互竞争的可能性。     

1,8-二甲氧基乙基萘的合成

以1,8-二萘酸酐为原料,经氢化铝锂还原得1,8-二羟甲基萘(2);2经浓盐酸酸化生成1,8-二氯甲基萘(3);3经氢化铝锂还原为1,8-二甲基萘(4);用强碱丁基锂和叔丁醇钾将4转化成二钾盐后与甲氧基氯甲烷反应合成了1,8-二甲氧基乙基萘,其结构经1H NMR和13C NMR和HR-MS表征.     

含锂碱金属盐类混合物中锂及铷、铯、钠的连续非水络合光度滴定

本文提出一种非水络合光度滴定法,不仅可用于测定含锂碱金属盐类混合物中的锂和碱金属总量,也可用于连续测定含锂二元碱金属盐类混合物中的锂和铯(或铷,或钠),其共存摩尔比为1∶5至5∶1。探讨了滴定过程的化学反应机理。发现离子势与铜(Ⅱ)相近,与铜(Ⅱ)同属生色离子的钴(Ⅱ)、镍(Ⅱ)也可用作锂盐的光度滴定剂。     

昆虫信息素的研究(Ⅴ)——家蝇性诱剂(Z)-9-二十三碳烯的合成

1971年Carlson等首先从雌性家蝇(Musca domestica)表皮类脂物和粪便类脂物中分离、鉴定并且合成了(Z)-9-二十三碳烯^[1],命名为muscalure,这个化合物对雄蝇具有引诱作用,其后陆续报道了这个化合物的一些合成方法^[2-6],其中美国Zoecon公司Carney等使用易得的油醇为原料,经甲基磺酰氯-三乙胺处理转变成甲基磺酸油酯,在铜盐催化下与正戊基镁溴化物偶联的方法提供了该产品商品化生产的路线^[6].     

Metallorganische verbindungen der lanthanoiden: XX. Cyclopentadienyllutetiumderivate von triphenylmethylenphosphoran

Tricyclopentadienyllutetium tetrahydrofuranate reacts with triphenylmethylenephosphorane with the formation of tricyclopentadienyllutetium triphenylmethylenephosphorane. A lutetium-containing metallacycle, 1,1-diphenyl-3,3-dicyclopentadienyl-1-phospha-3-luteto-indane, is formed by the decomposition of dicyclopentadienyl(methyl)lutetium triphenylmethylenephosphorane, by the reaction of dicyclopentadienylchlorolutetium triphenylmethylenephosphorane with sodium hydride or by the reaction of dicyclopentadienyllutetium chloride with lithium triphenylphosphonium methylide, respectively. The ¹H and ¹³C NMR spectra of the new compounds are discussed.     

Preparation and some reactions of 3,5:8,10-di-1,3-benzo[8](3,4)-1,2,5-thiadiazolocyclophane

Titled 1,2,5-thiadiazolometacyclophane 1 was prepared via thia[2.3]cyclophane 5 which was obtained by the reaction of di(bromomethyl) 2 with sodium sulfide under phase-transfer-catalyzed conditions. Cyclophane 1 gave the corresponding pyrene derivatives by the oxidative transannular reaction in the reaction with brominating reagent. Reduction of 1 with lithium aluminum hydride followed by acetylation with acetic anhydride gave a 4:l-mixture of cis- and trans-diamide 11 and 12 with a trace amount of cyclophane-ring-cleaved product 13 . On the other hand, 13 was obtained as a major product in the reduction with metal sodium and diisobutylaluminum hydride.     

Hydrooligomerization of Butadiene with Nickel Complex Catalyst

Abstract

Oligomerization of butadiene with the catalyst system of nickel(II)chloride, electron donor, and lithium aluminum hydride or sodium borohydride has been studied. Most oligomers obtained with this catalyst were linear, and dihydrogenated dimers, trimers, and tetramers. They were n-octa-1,6-diene, n-octa-1,7-diene, n-dodeca-1,6,10-triene, and n-hexadeca-1,6,10,14-tetraene, which were identified by means of infrared, nuclear magnetic resonance, and mass spectrometry. Yields of each oligomer were strongly affected by the nature of the electron donors used. The hydrogen required for the formation of the hydrooligomers was assumed to originate from the lithium aluminum hydride or sodium borohydride used as a reducing agent. A proposed mechanism for the hydrooligomerization is that butadiene is oligomerized on the nickel atom, and the produced oligoolefins, bonded to the nickel by two terminal π-allylic bonds, are dihydrogenated to linear hydrooligomers.     

Peculiarities of nucleophilic substitution in indolyliodonium salts

3-Indolylphenyliodonium trifluoroacetate reacts with ammonium bromide and lithium chloride and bromide to give 3-haloindoles. The reaction with ammonium chloride and tetrabutylammonium chloride leads to a mixture of 2- and 3-chloroindoles. The same mixture of chloroindoles is also formed by the action of lithium chloride but in the presence of 15-crown-5 ether. The course of the reaction is explained by ambident reaction of the cation of the iodonium salt.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1494–1496, November, 1981.     

Derivatization of organometal(loid) species by sodium borohydride problems and solutions.

Like other derivatization techniques, hydride generation is a chemical reaction that produces side-reactions leading to analytical problems. Demethylation of dimethylarsinic acid was observed to be dependent upon the pH level of the hydride generation reaction mixture. If the reaction mixture was acidic, then in addition to (CH3)2AsH, the monomethyl arsenic hydride [(CH3)AsH2] could be detected. Demethylation and also the formation of an unidentified arsenic species were noted when trimethyl arsonic oxide was used as derivatization educt. All of these effects depend on the pH level of the hydride generation mixture. We observed significant levels of organometal(loid) species of elements such as Ge, As, Sn, Sb, Hg and Bi in blank hydride generation mixtures. The organometal(loid) contamination was irreproducible even during I day using a single solution of sodium borohydride in deionized water. We concluded that the organometal(loid) contamination arises directly from the derivatization agent, sodium borohydride, itself. Use of helium purging and various adsorptive materials to decontaminate the sodium borohydride solution prior to analysis did not result in a significant decrease in organometal(loid) contamination levels. Use of a palladium-cluster stabilised with 1,10-phenanthrolin as alternative hydride generation derivatization agent was not found to be suitable, since reaction yields were poor and transmethylation reactions were noted.     

Ring opening reaction of N-substituted dihydropyrimidines with metal hydride complexes

N-Substituted dihydropyrimidines, 1, 3 , and 4 , easily afforded N,N′-disubstituted 2,4-diaminopentanes 2 in good yield by the ring opening reaction with sodium borohydride. The reaction with lithium aluminum hydride was also examined.     

Heterotricyclodecane XXIII 2-Thia-7-aza-isotwistane

2-Thia-7-aza-isotwistanes . The access to the 2-thia-7-aza-isotwistane system was achieved by water addition to the twistene 1 yielding the isotwistanol 2 , characterized also as its acetate 4 . Analogous D₂O/D₂SO₄-treatment of the twistene 1 (→ 3 ) allowed to deduce the reaction pathway for the formation of 2 . The chloride 6 , obtained from 2 , on treatment with lithium aluminium hydride gave a mixture of unsubstituted isotwistane 8 and twistane 9 , whereas silver acetate treatment of 6 led to the isotwistyl acetate 4 and possibly only to traces of the corresponding twistyl acetate 7 .     

Organoboranes : XVII. Reaction of organometallics with dialkylborane derivatives: The synthesis of mixed organoboranes not available via hydroboration

The reaction of organolithium reagents with methyl-dialkylborinates in hydrocarbon solvents proceeds readily with precipitation of lithium methoxide and the formation of the corresponding mixed organoborane:

Consequently, simple filtration of the reaction mixture gives the mixed organoborane in high yield and purity. Other dialkylborane derivatives, such as the chloride and the hydride, are less desirable as substrates, frequently resulting in isomerization of the new alkyl groups.     

Alkali salts of C3-symmetric,linked aryloxides: selective binding of substrates with metal aggregates

The lithium, sodium, and potassium salts of tris(3,5-dialkyl-2-hydroxyphenyl)methanes (tert-butyl, tert-pentyl, methyl) have been prepared by reaction of the triarylmethane with n-butyllithium, sodium hydride, and potassium hydride, respectively. These compounds are all hexanuclear aggregates composed of two triarylmethane units. Whereas the lithium salt is compact and cannot bind oxygen-donor solvent molecules, the sodium and potassium systems have vacant coordination sites that can interact with solvents. For the sodium compounds, the solvent can be subsequently removed, and the resulting coordinatively unsaturated compounds have been shown to selectively bind oxygen-donor substrates (ethers, aldehydes, and ketones) of suitable size and shape. The paper reports the synthesis and characterization of these novel compounds, including thirteen crystal structures of the salts and their adducts.