One-pot Synthesis of α,β-Dehydroamino Derivatives from β,β-Dicyanostyrene with 1,3-Dibromo-5,5-dimethylhydantoin Promoted by Mild Base

The reaction of β,β-dicyanostyrene derivatives(1) with 1,3-dibromo-5,5-dimethylhydantoin(DBDMH) was systematicly studied. The reaction could generate different products when promoted by different mild bases. When the reaction was promoted by NaOAc(100%, molar ratio to compound 1), β,β-dicyanostyrene derivatives could be directly converted into corresponding α,β-dehydroamino derivatives in good to excellent yields in one-pot. When the reaction was promoted by K₃PO₄(80%, molar ratio to compound 1), the corresponding α,β-dehydroamino and double-α,β-dehydroamino compounds were simultaneously obtained and the total conversion of β,β-dicyanostyrene derivatives was up to 90% or higher.     

Base-catalyzed Formation of Enamines from β,β-Dicyanostyrene Derivatives with N-Bromosaccharin

A new method for the synthesis of functional enamines from β,β-dicyanostyrene derivatives and N-bromosaccharin(NBSA) was developed. In the presence of Na₂CO₃, the the reaction of β,β-dicyanostyrene derivatives with NBSA can generate the corresponding enamines smoothly in a mixed solvent of dichloromethane and N,N-dimethylformamide (DMF)(volume ratio 1:1) at 50℃. The reaction of 14 kinds of β,β-dicyanostyrene derivatives with NBSA was investigated. Screened olefins afforded the corresponding enamines in good to excellent yields(up to 94%), indicating that the method has a wide adaptability for the substrate. The catalyst used is inexpensive and stable for storage. The amino groups of all products in their structures are on the α-position of products, revealing the reaction has an excellent regioselectivity. The possible pathway involving aminobromination of β,β-dicyanostyrene derivative with NBSA first and then elimination of HBr process in one pot has been proposed. The structures of all products were confirmed by ¹H NMR, ¹³C NMR and HRMS analysis.     

烯基取代的甲酸态四氢叶酸辅酶模型的合成及其碳单元转移反应

以邻苯二胺和乙酸为原料,经3步反应合成了8种烃基乙烯基取代的苯并咪唑盐,其结构用元素分析,¹HNMR,IR,MS和UV-Vis进行了表征,并以其作为取代的甲酸态四氢叶酸辅酶模型,同亲核试剂(格氏试剂)反应得到烃基乙烯基取代的一碳单元完全转移的产物α,β-不饱和酮,为α,β-不饱和酮的合成提供了一种简便的仿生合成新方法.     

α-乙酰基二硫缩烯酮的新合成方法

本文采用酸为催化剂，实施了具有代表性的各种烷硫基α,α-二乙酰基二硫缩烯酮的脱乙酰基反应，得到了一条简洁、通用的α-乙酰基二硫缩烯酮的合成路线.用浓硫酸作催化剂，以极高的产率(90%—100%)制得到相应的α-乙酰基二硫缩烯酮.同时，通过控制反应时间，还可以得到硫代乙酰乙酸酯类化合物.     

A new and efficient method for the synthesis of rocuronium bromide

Rocuronium bromide has been used as an aminosteroid non-depolarizing neuromuscular blocker and muscle relaxant.In this work,a new and efficient route for preparing a key intermediate 2β-(4-morpholinyl)-16β-(1-pyrrolidinyl)-5α-androstan-3α,17β-diol(6) was developed through a ring-opening of epoxide followed by introducing and pyrrolidine.Compound 6 can easily provide rocuronium bromide and the overall yield of compound 6 in 5 steps increased to 57.8%,which was higher than currently reported methods.Extraordinarily,this method would avoid the generation of disubstituted impurities E and F which are difficult to remove.     

One-step synthesis ofα,β-unsaturated arylsulfones by a novel multicomponent reaction of aromatic aldehydes,chloroacetonitrile, benzenesulfinic acid sodium salt

A new and green method for the synthesis of α,β-unsaturated arylsulfones had been achieved through the condensation of aromatic aldehydes,chloroacetonitrile,benzenesulfinic acid sodium salt in the presence of l-butyl-3-methyl imidazolium hydroxide([bmim]OH) in EtOH under reflux.The ionic liquid was recovered and recycled for subsequent reactions.The advantages of this protocol were non-toxic,easy work-up and good yields.     

Decarboxylative bromination of α,β-unsaturated carboxylic acids via an anodic oxidation

A novel bromination of α,β-unsaturated carboxylic acids was developed via a decarboxylation by virtue of a direct anodic electro-oxidation.In this method,ammonium bromide was employed as a bromine source and the reaction features transition-metal-free,short time,and no additional supporting electrolyte.     

4-羰基-2-戊烯醛与硫代乙酸加成的研究

以2-甲基-2,5-二甲氧基-2,5-二氢呋喃水解产物与硫代乙酸加成并在不同条件下关环,制得了β-乙酰硫基呋喃、噻吩和毗咯的各种异构产物,提供了按需要制备不同α-甲基-β-巯基呋喃、噻吩和吡咯衍生物的途径。     

铑-ImiFerroPhos配合物对β-取代-α,β-不饱和磷酸酯的不对称氢化

将手性二茂铁双膦配体ImiFerroPhos应用到β-取代-α,β-不饱和磷酸酯的不对称氢化反应中,在温和的反应条件下,以高收率及较高对映选择性合成了一系列β-取代的手性磷酸酯,最高获得了92%的ee值.     

Ca2+诱导的淀粉液化芽孢杆菌α-淀粉酶分子的生物活性和结构变化

在研究Ca²⁺对淀粉液化芽孢杆菌α-淀粉酶分子生物活性影响的基础上, 采用荧光光谱法和傅里叶变换红外光谱法研究了Ca²⁺诱导的酶分子结构变化. 结果表明, 当溶液中Ca²⁺浓度低于25.0 mmol/L时, Ca²⁺对酶分子具有激活作用; 而当Ca²⁺浓度高于25.0 mmol/L时, Ca²⁺对酶分子的生物活性具有抑制作用. 在Ca²⁺诱导的淀粉液化芽孢杆菌α-淀粉酶分子结构变化过程中, 酶分子仅发生二级结构的变化, 并不涉及其三级结构. 当Ca²⁺对酶分子具有激活作用时, 酶分子中的无规卷曲结构及β-折叠结构的含量下降, 而α-螺旋结构及β-转角结构的含量上升; 而当Ca²⁺对酶分子生物活性具有抑制作用时, 酶分子中的α-螺旋结构及β-转角结构的含量下降, 而无规卷曲结构及β-折叠结构的含量上升.     

α,α-二乙酰基二苄硫缩烯酮的碱催化脱乙酰基反应及缩合反应机理研究

α-羰基二硫缩烯酮是一类极其重要的有机合成中间体，烷硫基对该类具有推-拉电子效应的共轭体系的性质影响很大。据此，我们率先提出了烷硫基对α-羰基二硫缩烯酮类化合物的化学行为具有调控作用的观点，并将其归因于空间电子因素的作用，α-乙酰基-α′-羰基二苄硫缩烯酮(1)具有多反应性特征。近来，我们利用该特征在氢氧化钠催化下通过化合物1的环合合成了多取代噻吩类化合物；在乙醇钠-醋酸铅作用下经乙氧基对化合物1的苄硫基的取代实现了α-羰基-O，O-缩烯酮的合成。     

α,α-二乙酰基二硫缩烯酮和芳醛的缩合反应研究

在碱性条件下,α,α-二乙酰基二硫缩烯酮和芳醛的缩合反应受烷硫基的影响.α,α-二乙酰基二苄硫缩烯酮1和芳醛3缩合生成单面缩合脱乙酰基产物α-肉桂酰基二苄硫缩烯酮4;α,α-二乙酰基环二硫缩烯酮2和芳醛3缩合生成双面缩合产物α,α-二肉桂酰基环二硫缩烯酮5.     

Asymmetric hydroazidation of α-substituted vinyl ketones catalyzed by chiral primary amine

We report herein the first example of asymmetric hydroazidation of α-substituted vinyl ketones by using chiral primary amines as the catalysts.A simple chiral primary-tertiary diamine catalyst derived from lphenylalanine was found to readily promote this aza-Michael addition reaction with enamine protonation as the key stereogenic step,thus enabling the effective synthesis of α-chiral β-azido ketones with good yields and moderate enantioselectivities.     

含硫碳负离子的反应及其应用的研究(Ⅰ)——固-液相转移催化法合成取代肉桂酸酯

虽然含硫碳负离子在有机合成中已有若干应用^[1~4],但要有效地产生这类碳负离子,通常需用有机锂或氢化钠,这些强碱性试剂对氧和潮气都很敏感,在实际应用方面有不足之处。     

α-氯丙酸乙酯对映体与β-环糊精的主客体相互作用

运用量子力学PM3方法模拟α-氯丙酸乙酯((R/S)-ECPA)与β-环糊(β-CD)的主客体相互作用, 探讨(R/S)-ECPA在β-CD上的手性识别机理. 结果表明, (R/S)-ECPA对映体与β-CD形成稳定结合物的结合方式完全不同, (R)-ECPA位于β-CD空腔宽口端, 形成缔合物; (S)-ECPA插入β-CD空腔内形成包结物. 而且, (S)-ECPA与β-CD的结合稳定能低于(R)-ECPA与β-CD的结合稳定能. 在(R/S)-ECPA与β-CD结合物中, (R/S)-ECPA中的手性碳接近葡萄糖单元的C2和C3. (R/S)-ECPA与β-CD之间的手性识别与葡萄糖单元的C2和C3所提供的手性环境和(R/S)-ECPA与β-CD结合的紧密程度密切相关.     

新的α/β水解酶W14和W15的三维结构模建及分子对接研究

利用同源模建和分子动力学模拟方法, 模建了两个新发现的α/β水解酶超家族成员W14和W15的三维结构, 并通过与α-醋酸萘酯的对接研究, 从理论上提出Gly82和Val13为形成“氧洞”的关键残基,有利于稳定水解过程中的带负电的过渡态, 以及其它对复合物形成起到重要作用的氨基酸残基.     

Enantioselective trapping of oxonium ylide intermediates by N-benzhydryl-α-imino ester:Synthesis of β-tetrasubstituted α-amino acids

A synergistic rhodium(Ⅱ)/phosphoric acid catalyzed three component reaction of 3-diazooxindoles,alcohols and N-benzhydryl-α-imino ester is developed for the efficient construction of chiral β-alkoxy C~β-tetrasubstituted α-amino acid derivatives in good yields and with excellent diastereoselectivities and high enantioselectivities.The synthetic application of the resulting products was illustrated by reducing with Pd/C under H_2 atmosphere followed reacting with CSCl_2 at room temperature to rapid afford 3-spirocyclic oxindole in a good yield with a chirality retainment.The three-component reaction is proposed to proceed through an electrophilic trapping of the oxonium ylides by N-benzhydryl-α-imino ester.     

单分散α-Fe_2O_3纳米结构空心亚微球的制备及表征

采用一种新的溶液生长法结合多步包覆法在自制的不同粒径SiO2单分散亚微球表面包覆不同厚度的β-FeOOH涂层,得到单分散β-FeOOH/SiO2核壳结构亚微球.实验结果表明,SiO2核心颗粒尺寸对表面涂层的形态和包覆均匀性有很大影响.当SiO2核心颗粒的平均粒径为250 nm左右时,β-FeOOH表面涂层均匀,颗粒间团聚较少,一次包覆后涂层厚度约为35 nm.涂层中β-FeOOH纳米棒的尺寸随着所选SiO2核心颗粒粒径的增大而相应增大.经多次包覆能够显著提高涂层的厚度,3次包覆后β-FeOOH表面涂层厚约100 nm.β-FeOOH/SiO2核壳结构亚微球与质量分数5%的NaOH溶液反应后,于600℃焙烧2 h得到了单分散α-Fe2O3空心微球.单分散α-Fe2O3空心亚微球表层是由α-Fe2O3纳米棒搭建而成的三维网络结构,α-Fe2O3纳米棒的尺寸与核壳结构中β-FeOOH纳米棒的尺寸基本一致.     

Two new steroidal alkaloids from Veratrum nigrum var. ussuriense

<正>Two new steroidal alkaloids,veraussines A(1) and B(2) were isolated from the roots and rhizomes of Veratrum nigrum var.ussuriense.Their structures were determined as N-(ethoxycarbonyl)- 1α,2β,3α,15α-tetrahydroxy-5β-jervanin- 12-en- 11-one(1) andN-(methoxycarbonyl)- 1α,2β,3α,15α-tetrahydroxy-5β-jervanin- 12-en- 11 -one(2) by spectroscopic analysis.     

毛细管电泳测定4个不对称合成化合物的光学纯度

采用毛细管电泳技术,以α-环糊精、β-环糊精和β-环糊精聚合物为手性选择剂,对4种不对称合成物3-(二乙基氨基)-1-苯基-1-丙醇(a)、1-苯基-3-(1-哌啶）-1-丙醇(b)、3-吗啉-1-对甲苯基-1-丙醇(c)和1-（4-氯苯基）-3-吗啉-1-丙醇(d)的消旋体和光学活性异构体进行了手性分离。 结果发现,使用20 kV的分离电压,以浓度为30 g/L的β-环糊精聚合物的80 mmol/L三羟甲基氨基甲烷缓冲溶液（pH=3.2）为背景电解质溶液,4种化合物在40 min内均可得到基线分离。 根据对映异构体峰面积和保留时间的比值确定了4种不对称化合物的光学纯度。 测定的RSD均不大于1.5%。