高含水聚乙烯醇弹性体

本文介绍了用反复冻结～融溶过程制备高含水聚乙烯醇弹性体的方法,并测定了该弹性体的机械、溶解和溶胀性能。结果表明,该弹性体可同时具有很高的含水率(85—90％)和较高的抗张强度(10~5—10~6Pa),且在37℃的水中有良好的稳定性能。     

Direct catalytic asymmetric Mannich-type reactions of isomerizable aliphatic imines: chemoselective enolate formation from a hydroxyketone by a Zn-catalyst

A direct catalytic asymmetric Mannich-type reaction of isomerizable aliphatic imines is described. A Et₂Zn/(S,S)-linked-BINOL complex was suitable for chemoselective enolate formation from a hydroxyketone in the presence of isomerizable aliphatic N-diphenylphosphinoyl imines. The reaction proceeds smoothly and β-alkyl-β-amino-α-hydroxyketones were obtained in good yield and high enantioselectivity (up to 99% ee), albeit in modest to low diastereoselectivity.     

Reaction kinetics of the selective liquid phase hydrogenation of styrene oxide to β-phenethyl alcohol

Liquid phase hydrogenation of styrene oxide using 1% Pd/C and NaOH as a promoter was found to give selectively β-phenethyl alcohol (PEA) under very mild conditions (313–333 K; 0.68–5.5 MPa). The kinetics of this system was investigated by collecting initial rate data in a batch slurry reactor. Rate of hydrogenation was found to decrease beyond a certain concentration of both hydrogen (>3 MPa) and styrene oxide (>0.5 kmol/m³). A Langmuir–Hinshelwood type rate equation has been proposed based on the initial rate data in the kinetic regime. The model predictions agree very well with the experimentally observed concentration–time data indicating the applicability of the proposed rate model.     

冻干保护剂溶液低温退火特性的研究

利用差示扫描量热仪(DSC)研究了10%叔丁醇/10%蔗糖/水溶液的冻结特性, 退火温度及退火时间, 分析了溶液的退火行为. 实验结果表明, 溶液降温时, 蔗糖的存在阻碍了叔丁醇析出, 最大冻结浓缩溶液玻璃化转变温度Tg′由－32.5 ℃降低到－42.0 ℃, 升温时在－30 ℃叔丁醇发生反玻璃化. 在反玻璃化峰附近的温度进行退火可使叔丁醇充分析出, Tg′由－42.0 ℃上升到－34.9 ℃. 所需的退火时间与退火温度有关, 退火温度越接近Tg′, 所需的退火时间越长. 在－37 ℃时, 退火20 min可完全消除反玻璃化.     

多花蔷薇花净油化学成分研究

多花蔷薇(Rose multiflora. cathayensis)又名红刺玫、刺花,系多年生落叶灌木,野生于甘肃省陇南山区,生长在海拔500～1900 m的山峰、河岸或山坡缘及灌木丛林中,花的资源丰富,是甘肃省目前需开发的野生芳香植物之一,多花蔷薇花为粉红色,花期为5月中旬至5月底,花中含芳香油,可用作化妆、皂用香精等,有关多花蔷薇花的化学成分,未见文献报道,我们将多花蔷薇花的石油醚浸膏用乙醇在0℃脱蜡3次得净油,再经硅胶柱层析分离得纯     

Interaction of Methyl 5,6-Dialkyl-2-amino-3-cyanopyridine-4-carboxylates with Primary Amines

An unusual direction has been found for the interaction of alkyl 5,6-dialkyl-2-amino-3-cyanopyridine-4-carboxylates with primary amines leading to the formation of 2,6,7-trialkyl-4-amino-2,3-dihydro-1H-pyrrolo[3,4-c]pyridine-1,3-diones.     

Molecular and absolute crystal structure of pindolol-1-(1H-indol-4-yloxy)-3-[(1-methylethyl)amino]-2-propanol: A specific beta-adrenoreceptor antagonist with partial agonist activity

The crystal and molecular structure of pindolol, 1-(1H indol-4-yloxy)-3-[(1-methylethyl)amino]-2-propanol, has been determined by direct methods. Crystals are tetragonal, ,a=b=15.809(4),c=11.246(2) Å,Z=8,D _c=1.174 mg m^–3. The finalR-factor for 2271 reflections withI>2(I) is 0.038. Refinement by full-matrix least-squares on F² also enabled the absolute configuration of the structure to be established. The molecule is essentially planar, including much of the side-chain which is stabilized by the existence of two intramolecular H-bonds, between the ethyl oxygen and OH group, and between the OH and side-chain amide groups, respectively. The crystal structure is formed by three intermolecular hydrogen bonds including two side-chain-side-chain interactions, between ethyl oxygen to amide and OH to amide, and an interaction between the side-chain OH to indole NH.     

由水杨醇衍生的二苯并冠醚的合成和构型

将水杨醇在ＤＭＦ中与ＮａＨ和二甘醇或三某醇二对甲苯磺酸酯反，合成了２个新的二苯并冠醚（１和２），其结构由元素分析和波谱分析所表征，１ 射线衍射分析确定为反位构型，提出了合成反应的机理。     

A unique reversal of elution order during direct enantiomeric resolution of amide derivatives of 1-phenyl-2-aminopropane by high performance liquid chromatography on chiral stationary phases

Enantiomeric amide derivatives of (S)- and (R)-1-phenyl-2-aminopropane (dextro- and levoamphetamine, respectively) were resolved by high performance liquid chromatography on commercially available ionically and covalently bonded chiral stationary phases ((R)-N-(3,5-dinitrobenzoyl)phenylglycine). Ten enantiomeric amide pairs were synthesized and chromatographed on the columns by using a mobile phase of hexane-isopropanol (97 : 3), a flow rate of 2 ml/min, and a column temperature of 20°C. The (R)-isomer of all 10 amides eluted first on the covalent column as did the (R)-isomer of nine derivatives on the ionic column. however, the 3,5-dinitrobenzoyl amide of (S)- amphetamine eluted before the (R)-isomer on the ionic column. This reversal in enantiomeric elution order reveals the complexity of the interactions occurring on these columns and emphasizes the hazards of relying on observed elution order as an a priori indication of absolute configuration.     

酰胺型萃取剂N-503的合成

酰胺型萃取剂N-503[N,N-二-(1-甲基庚基)乙酰胺]可以用甲庚醇或2-氯代辛烷为原料来合成。它的重要中间体二-(1-甲基庚基)胺的制备方法有二:一是从甲庚醇制备的方法,将甲庚醇用阮来镍催化,常压氨解,得率95～99％左右;二是从2-氯代辛烷制备,此法需要高压设备,得率35％左右。第一个方法在扩大试验中,产率和产品质量都比较好,是一个较好的制备长碳链仲胺的方法。