L-脯氨酸催化下甲基酮和1-芳基-2,2,2-三氟乙酮的不对称Aldol反应

Direct asymmetric aldol addition of methyl ketones to 2,2,2-trifluoro-1-phenylethanone and its ring-substituted derivatives was achieved using L-proline as a chiral promoter. Various optically active β-trifluoromethyl-β-hydroxy ketones were obtained in almost quantitative yields with moderate enantioselectivities up to 64 % ee.     

A Convenient Approach to the Enantiopure （1S, 2S, 4S, 5S ）- and（ 1R, 2S, 4R, 5 S ）-2,5-Bis （ phenylmethyl）-l, 4-diazabicyclo[ 2.2.2 ] -octane

Cyclodipepflde (3S, 6S )-bis (phenylmethyl) piperazlne-2,5-dione was prelmred in high yield by heating phenylalanine methyl ester in toluene under reflux. The reduction of this cydodipeptide with sodium NaBH4-BF3 in DIME gave the (2S ,SS)-bis(phenyl-methyl)plperazine, which, on heating with ethylene bromide and triethyiamine, afforded the title compounds. This methodwas proved to be generally applicable to the synthesis of C2-symmetric 2, 5-disubsiituted=l, 4-diazabicyclo [ 2.2.2 ] octanefrom the corresponding natural or unnatural amino acid esters.     

三角帆蚌钩介幼虫体外培养及变态稚贝的形态变化

以超纯水为对照,利用普通温控培养箱,在(24.0±1.0)℃条件下对三角帆蚌钩介幼虫进行了15d的体外培养实验.结果显示:钩介幼虫排出体外24h内存活率显著下降为50.7%(p=0.006);A组(MEM高糖)、B组(RPMI1640)、C组(MEM 199)幼虫变态率分别为(7.5±3.9)%、(13.3±12.0)%、(42.1±10.0)%;D组(L-15)的幼虫变态率最高,为(66.1±3.8)%,极显著高于C组(p=0.007).相关分析表明,培养液中葡萄糖含量与钩介幼虫变态率存在显著负相关(r=-0.886).利用光镜和扫描电镜对体外培养变态发育的稚贝形态观察发现:稚贝双壳表面圆形凹陷数量和深度比幼虫显著减少,双壳边缘外套膜增厚,在外套膜、斧足表面分布有大量乳状突起,但形态不同.体外培养稚贝的外部形态和内部器官均发生了显著改变,完成了变态发育过程.     

由α-羰基一硫代半缩醛合成含氮杂环化合物

利用α-羰基一硫代半缩醛和含氨基的化合物反应,合成了六员含氮杂环化合物,其结构通过红外、核磁、质谱和元素分析得到了证实.     

从脯氨酸合成一种三齿手性配体及其在二乙基锌对醛的对映选择性加成中的应用

A new chiral tridentate ligand [1-(1-methyl-S-pyrrolidin-2-ylmethyl)-S-pyrrolidin-2-yl]-diphenylmethanol (1) has been successfully synthesized from S-proline. The structure of the ligand was characterized by NMR spectra and X-ray diffraction analysis. Its catalytic ability has also been examined in enantioselective addition of diethylzinc towards aldehydes with 15%-84% enantiomeric excesses (ee).     

A Convenient Approach to the Enantiopure (1S,2S,4S,5S)-and (1R,2S,4R,5S)-2,5-Bis(phenylmethyl)-1,4-diazabicyclo[2.2.2]-octane

Introduction1,4 Diazabicyclo[2 .2 .2 ]octane (DABCO)wasre portedtocatalyzeorganicreactionsduetoitsstrongbasici ty .1,2 Severalchiraltrans 2 ,3 disubstitutedDABCOshavebeensynthesizedandappliedtotheasymmetricBaylis Hillmanreaction3andvicinalhydroxylation .4ThefirstsynthesisofthetitlecompoundwasreportedbySoai5from (2S ,5S) bis(phenylmethyl)piperazine (1) ,asshowninScheme 1.Butthisprocedureislengthy ,andtheoverallyieldisnotsosatisfactory .Besides ,thereport edmethodforthepreparationof 1is…     

手性氨基醇的合成及其在二乙基锌与芳香醛的不对称加成反应中的应用

以天然氨基酸为手性源,合成了3个新的三齿手性氨基醇配体(1a～1c),其结构经1H NMR, IR和元素分析表征.将1用于催化二乙基锌与芳香醛的不对称加成反应,得到(R)-二级醇,产率96.7%, e.e.74.3%.     

α-羰基一硫代半缩醛与脂肪族脲反应合成2, 4-咪唑啉二酮衍生物

利用α-羰基一硫代半缩醛与脂肪基取代脲反应合成了六个新的咪唑啉二酮类衍生物。并用IR,NMR,MS和元素分析进行测定,最后用X四圆衍射仪确定了它们的结构。     

α-碳基—硫代半缩醛与脂肪族脲反应合成2,4-咪唑啉二酮衍生物

利用α-羰基—硫代半缩醛与脂肪基取代脲反应合成了六个新的咪唑啉二酮类衍生物,并用IR,NMR,MS和元素分析进行测定,最后用X四圆衍射仪确定了它们的结构.     

由α—羧基—硫代半缩醛合成含氮杂环化合物

利用由α-羧基－硫代半缩醛和含氨基的化合物反应,合成了六员含氮杂环化合物,其结构构通过红外,核磁、质谱和元素分析得到了证实。