2,8-二氨基-10-羟基-5-甲基-5,10-二氢磷杂吖嗪-10-氧化物的合成及其诱变性研究

在升温条件下,二苯胺和三氯化磷反应,产物经水解、氧化得次膦酸:10-羟基-5,10-二氢磷杂吖嗪-10-氧化物(产率45%).经酰化后,与甲醇钠作用,生成相应的次膦酸甲酯.次膦酸甲酯经NaH处理后,在120℃下发生甲基迁移,形成5-甲基次膦酸(产率62%).用45倍摩尔量的硝化剂将5-甲基次膦酸硝化,得到双硝基产物(产率59%).在5%Pd/C催化下,双硝基产物又被氢气还原.考察催化剂用量对该还原反应的影响,并在最佳催化剂用量时得到2,8-二氨基-10-羟基-5-甲基-5,10-二氢磷杂吖嗪-10-氧化物(产率70%).用NMR,IR和质谱确定了所合成的5个中间体结构.对合成的氨基化合物进行Salmonella/mam-malianmicrosomeassay测试,结果表明,该氨基化合物表现为非诱变性.     

离子液体中扁桃酸乙酯的酶促不对称水解

对脂肪酶在离子液体中不对称水解扁桃酸乙酯制备R-扁桃酸进行了研究,发现脂肪酶N435在离子液体[BMIM]Br中的活性和立体选择性最高.研究了离子液体浓度、底物浓度、反应时间、反应温度、缓冲液pH值和摇床转速等因素对反应的影响,适宜反应条件为:1.39mol/LDL-扁桃酸乙酯、1.71mol/L[BMIM]Br、Tris-HCl缓冲液pH7.5、10mgN435酶、30℃、150r/min反应6h,该条件下产物对映体过量值(ee)可达58.78%,产率为65.23%,并对离子液体进行了重复利用.     

L-亮氨酸衍生物手性氨基醇的合成及其对布洛芬和扁桃酸对映异构体的手性识别

对甲基苯胺经甲基化、甲酰化得到5,N,N-三甲基-2-氨基苯甲醛;对L-亮氨酸经酯化、格氏反应得到二齿手性氨基醇.二齿手性氨基醇与上述醛经缩合、还原反应,得到三齿手性氨基醇.产物结构经IR,MS和1H NMR等进行了表征;通过改变主客体的浓度及手性羧酸的纯度,运用1H NMR分别考察了主体二齿手性氨基醇、三齿手性氨基醇对客体布洛芬和扁桃酸对映异构体的手性识别能力.结果表明:当主客体物质的量之比为1:1时,三齿手性氨基醇对布洛芬消旋体的a位甲基质子及扁桃酸消旋体的a位质子分别产生11.2和9.2 Hz的化学位移差值.     

7-取代-4-喹诺酮-2-羧酸甲酯的合成

4-喹诺酮-2-羧酸甲酯衍生物的制备,一般是用苯胺衍生物与丁炔二酸二甲酯反应,生成α-(取代苯胺基)丁烯二酸二甲酯(1),继之在二苯醚中约260℃加热环合而获得。我们用间氨基苯酚与丁炔二酸二甲酯在甲醇中反应,所得黄色固体经鉴定为7-羟基-4-喹诺酮-2-羧酸甲酯(2);除去固体后的滤液在甲醇-盐酸中回流还能生成2。若用间苯二胺与丁炔二酸二甲酯反应,则生成7-氨基-4-喹诺酮-2-羧酸甲酯(3)(产率20%)和N,N′-二(1,2-双-甲氧羰基乙烯基)间苯二胺(4)(产率4.8%)。这样就不需要再在二苯醚中进行环合。2与3的易于制备,显示氨基和羟基的活化作用。2和3在室温分别与醋酐-吡啶反应,可得乙酰化物5和6.2和3在二甲基甲酰胺中与乙氧草酰氯(ethyloxalyl chloride)反应,可分别生成化合物7和8。     

室温离子液体促进的5-亚芳基巴比妥酸衍生物的合成

在室温离子液体1-丁基-3-甲基咪唑四氟硼酸盐([bmim]BF₄)存在下, 采用室温研磨和微波辐射的方法, 由芳香醛和巴比妥酸或硫代巴比妥酸经Knoevenagel缩合反应, 制备了相应的5-亚芳基巴比妥酸或5-亚芳烃基硫代巴比妥酸衍生物. 在室温研磨条件下反应2 h, 产率为78%～96%, 在微波辐射功率为160 W时反应20 s, 产率为82%～98%, 产物结构经¹H NMR确证.     

β-氨基环己醇的合成

考察并优化了以1,2-环氧环己烷为起始原料,通过分子内Ritter反应并经唑啉环中间体制备β-氨基环己醇的各种反应条件.同时尝试了以1,2-环己二醇为起始物,进行分子内Ritter反应合成β-氨基环己醇的反应.由于1,2-环己二醇的反应活性相对较差,质子酸不能有效地催化该反应,使得后者制备β-氨基环己醇的产率较低.以环氧环己烷为起始物制备β-氨基环己醇的方法,具有操作简便、原料廉价等优点,其产品(2-氨基环己醇的盐酸盐)总收率达到了50%~60%.     

无金属催化合成3,3-二氟-2-氧化吲哚衍生物

发展了一种合成3,3-二氟-2-氧化吲哚及其衍生物的新方法。 以简单的芳香胺和溴二氟乙酸乙酯为起始原料,在无溶剂和N₂气保护下搅拌5 h,得到含二氟的氮乙酰苯胺衍生物中间体,产率85%~93%。 该中间体与碘甲烷反应,得到N-甲基保护的乙酰苯胺衍生物,产率75%~90%。 该衍生物在3.0化学计量促进剂次硫酸氢钠甲醛的存在下,以N,N-二甲基甲酰胺/H₂O为溶剂,发生分子内自由基关环反应,得到3,3-二氟-2-氧化吲哚及其衍生物,产率53%~72%。 该方法原料便宜,不使用任何金属化合物,最后一步以水相为溶剂,较为环保,具有潜在的工业应用价值。     

手性助剂法不对称合成γ-不饱和氨基酸

采用2-N-(N'-苄基脯氨酰)-氨基二苯甲酮-镍(Ⅱ)-甘氨酸复合物与2-N-(N'-苄基脯氨酰)-氨基二苯甲酮-镍(Ⅱ)-丙基酸复合物为手性助剂,与3-烯丙基溴进行取代反应,制备了2种手性非蛋白不饱和氨基酸.反应过程操作简便,复合物产率达90%～93%,2-氨基-4-烯-戊酸和2-甲基-2-氨基-4-烯-戊酸的总收率分别为75%和80%. 手性助剂回收率达90%. 中间产物及γ-不饱和氨基酸经1H NMR和质谱测试技术的确证.     

氨基的脱保护——乙酰苯胺水解实验教学设计*

通过开放性设计实验完成氨基脱保护实验的教学。指导学生以回收的乙酰苯胺为原料,自主设计乙酰苯胺在酸、碱条件下水解正交实验方案并分组独立操作,制备并提纯苯胺,比较不同条件下的苯胺收率,筛选出乙酰苯胺最佳的水解条件。对所选实验班级近3年的实验结果进行统计和分析,并通过验证实验考察了结果的可重复性。     

Alcaligenes faecalis CGMCC 1.2006整细胞催化邻氯扁桃腈动态动力学拆分制备（R）-邻氯扁桃酸

从6株粪产碱杆菌中筛选出对邻氯扁桃腈具有较高芳基乙腈水解酶活性和中等对映选择性的Alcaligenes faecalis CGMCC 1.2006.研究了反应介质对Alcaligenes faecalis CGMCC 1.2006芳基乙腈水解酶活性和对映选择性的调控作用.反应介质中水溶性辅溶剂如甲醇的加入降低芳基乙腈水解酶活性,但显著提高对映选择性.而非离子表面活性剂的加入具有相反的作用.系统优化了底物浓度、细胞浓度、pH、温度和反应时间等反应条件对芳基乙腈水解酶活性和对映选择性的影响.在最优反应条件下,采用分批补料策略,(R)-邻氯扁桃酸的产量在22 h内达到32.2 g/L,产率82.4%,ee 93.1%.以邻氯苯甲醛和氰化钾为底物合成(R)-邻氯扁桃酸,收率89.5%,ee98.6%.     

The dimethyldioxirane-mediated oxidation of phenylethyne

The product pattern found for the dimethyldioxirane-mediated oxidation of phenylethyne strongly depends on the reaction conditions. Dimethyldioxirane generated in situ from caroate (HSO(5)(-)) and acetone in acetonitrile-water furnishes phenylacetic acid as the main product. With solutions of dimethyldioxirane in acetone, mandelic acid and phenylacetic acid are mainly formed. The relative abundances of the two acids depend on the residual water present in the dimethyldioxirane-acetone solution. Application of thoroughly dried solutions of the reagent effects increased formation of mandelic acid. When phenylethyne is oxidized by dimethyldioxirane transferred into tetrachloromethane, to minimize traces of water even further, oligomeric mandelic acid is obtained. The results are rationalized by the initial formation of phenyloxirene, which is known to equilibrate with phenylformylcarbene and benzoylcarbene. Subsequent Wolff rearrangement produces intermediate phenylketene, which can be trapped by water as phenylacetic acid or suffer from further oxidation to the alpha-lactone of mandelic acid. The alpha-lactone can either react with water to yield mandelic acid or, under anhydrous conditions, to yield oligomeric mandelic acid. In addition to mandelic acid and phenylacetic acid phenylglyoxylic acid, benzoic acid and benzaldehyde are observed as reaction products. The formation of phenylglyoxylic acid by transfer of two oxygen atoms to the unrearranged carbon skeleton of phenylethyne followed by oxygen insertion into the aldehydic C-H bond of the intermediately formed phenylglyoxal is discussed. In a second pathway this acid is formed by partial oxidation of mandelic acid. Benzaldehyde and benzoic acid are explained as products of the oxidative degradation of the alpha-lactone by dimethyldioxirane. Under in situ conditions benzoic acid is also formed by caroate initiated oxidative decarboxylation of phenylglyoxylic acid and/or intermediate phenylglyoxal.     

强心药匹莫苯单水合物新合成方法研究

以乙酰苯胺和３－氯－２－甲基丙酰氯为起始原料，经８步反应即合成新型强心药匹莫苯单水合物，总收率达１７．３％，除对所涉及的硝化，还原反应及精制方法作了改进外，还首次报道了Ｐｉｍｏｂｅｎｄａｎ的结晶水形式。     

Kinetic Resolution of Racemic Mandelic Acid Esters by N,N′‐Dioxide–Scandium‐Complex‐Catalyzed Enantiomer‐Selective Acylation

A simple and efficient acylative kinetic resolution of racemic mandelic acid esters was accomplished with a chiral N,N’‐dioxide–scandium(III) complex under mild and base‐free reaction conditions. A variety of mandelic acid esters performed well in the reaction, obtaining both acylated products (up to 49% yield, 97% ee) and recovered substrates (up to 49% yield, 95% ee) in high enantioselectivities with perfect selectivity factors (up to 247). The enantioselective recognition and catalytic models were also proposed for the catalytic KR reaction.     

3-乙氧基-4-羟基苯乙醇酸在聚邻甲苯胺-Cu~(2+)膜电极上的电氧化

采用循环伏安法制备了聚邻甲苯胺(POT)膜电极,再以浸泡吸附法在此膜中嵌入Cu2+,制成POT-Cu2+膜电极.研究了POT-Cu2+膜电极对3-乙氧基-4-羟基苯乙醇酸的电氧化行为,并讨论了影响电氧化活性的主要因素.结果表明,50℃下,在含有0.5mol.L-13-乙氧基-4-羟基苯乙醇酸的1.5mol.L-1氢氧化钠溶液中,POT-Cu2+膜电极具有高的电氧化活性和良好的稳定性.将该电极用于3-乙氧基-4-羟基苯乙醇酸电解氧化脱羧制备乙基香兰素,在0.55V(vsSCE)下恒电位电解1h,乙基香兰素的产率可达89%以上,电流效率达97%以上.     

Trimerization of aldehydes with one α-hydrogen catalyzed by sodium hydroxide

Trimerization of 2-methylpropanal (isobutyraldehyde) is a simple and effective method to synthesize 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate and 2,2,4-trimethyl-1,3-pentanediol-3-monoisobutyrate which are often used as film forming auxiliaries in paints. The use of solid sodium hydroxide as a catalyst provides an excellent yield of above 85 % after the optimization of the reaction time and the catalyst dosage. Furthermore, trimerization of four other aldehydes with one α-hydrogen catalyzed by solid sodium hydroxide can also take place and the yield of 1,3-diol monoesters reaches 50–70 %. Trimerization of aldehydes with one α-hydrogen can be explained by a three-step reaction mechanism: (i) aldol condensation of aldehyde; (ii) crossed Cannizzaro reaction; and (iii) esterification of carboxylic acid and alcohol.     

Preparation of polymandelide by reaction of α-bromophenylacetic acid and triethylamine

Polymandelide was prepared in 77% yield by reaction of α-bromophenylacetic acid and triethylamine. The product was characterized by ¹H- and ¹³C-NMR and IR spectra and isolation and identification of mandelic acid from hydrolysis of the polymer. The NMR spectra indicate the presence of tacticity at CH in the polymer. Molecular weights were determined by GPC and viscosity measurements; n values of 12–20 are comparable to those reported for polymandelides prepared by other methods. The x-ray powder diffraction pattern showed the product to be completely amorphous. Thermal decomposition was studied using DSC.     

Determination of uranium in seawater samples by liquid chromatography using mandelic acid as a complexing agent

The determination of uranium at different stages of the recovery process as well as in seawater is important in its recovery study. A previous study developed a high-performance liquid chromatography (HPLC) method for uranium determination in seawater using α-hydroxy isobutyric acid as a chelating agent. However, this method causes turbidity in process samples containing high amounts of iron, resulting in the clogging of the HPLC column. In the present work, use of mandelic acid as a chelating agent for uranium has been explored. Elution conditions were optimized for the separation of iron [Fe(III)] and uranium [U(VI)] by studying the effect of an ion interaction reagent, the concentration of mandelic acid, and methanol content in the mobile phase. Different parameters were optimized to develop off- line pre-concentration of uranyl-mandelate on the reversed stationary phase. The method offers quantitative recovery of uranium and linearity in the U(VI) concentration range of 0.5 ppb to 500 ppb and can be used for the determination of U(VI) in process samples with Fe/U amount ratios up to 3,000. The method has been successfully used for the determination of U(VI) in seawater samples and process samples. The developed methodology was validated by comparing the results with those of isotope dilution-thermal ionization mass spectrometry.     

Electrochemical Reduction of Benzoylformic Acid in Ionic Liquid

Ionic Hquids possess a number of unique properties that makethem ideal electrolytes. Electrochical reduction of benzoyl-formic acid in room temperature ionic liquids as reaction media could be conducted with excellent performances without any ad-ditional supporting electrolyte. Electrolysis at glassy carbon electrode results in the formation of mandelic acid in 91% yield. And the electrochemical behavior of benzoylformic acid was investigated with the technique of cyclic voltammetry.     

Acetanilide palladacycle: an efficient catalyst for room‐temperature Suzuki–Miyaura cross‐coupling reaction

The catalytic activity of three acetanilide palladacycles derived from easily accessible and commercially available acetanilide derivatives, viz. N‐phenylacetamide ( L1 ), N‐(4‐chlorophenyl)acetamide ( L2 ) and N‐(4‐methylphenyl)acetamide ( L3 ) has been examined in Pd‐catalyzed Suzuki–Miyaura reaction of arylboronic acid with aryl bromides at room temperature. The complex 1L3 exhibited efficient activity in the Suzuki–Miyaura reaction (up to 99% isolated yield) under mild reaction conditions. Copyright © 2014 John Wiley & Sons, Ltd.     

Colorimetric enantiodiscrimination of mandelic acid by indicator displacement assay

The colorimetric enantiodiscrimination between mandelic acid and L-proline-Cu(II) is exploited to develop enantioselective indicator displacement assays. The sensitivity of the assay could be tuned by using a colorimetric indicator. The chromophoric ligand, pyrocatechol violet, effectively competes with the mandelic acid guest for open coordination sites on L-proline-Cu(II). The DA could be increased to 0.12 by changing the ratio of(+)- and(à)-mandelic acid concentrations that were found to be optimal from the displacement experiments. The resultant enantiomer excess versus DA relationship is linear. From the calibration curves, the absorbance values of the unknowns may be calculated for the enantiomeric excess value and the colorimetric enantiodiscrimination of mandelic acid can thus be obtained.