单层分散(L)-脯氨酸修饰的Pd/Al_2O_3催化剂上3,3,5-三甲基环己酮的动力学拆分

由异佛尔酮(IP)不对称加氢产物得到的手性(R-或S-)3,3,5-三甲基环己酮(TMCH)是非常重要的精细化工中间体。该文探究了(L)-脯氨酸修饰Pd/Al2O3催化剂上异佛尔酮的不对称加氢和3,3,5-三甲基环己酮外消旋体的催化加氢动力学拆分。研究发现,异佛尔酮和(L)-脯氨酸的缩合物会显著抑制异佛尔酮的不对称加氢反应。(L)-脯氨酸在Pd/Al2O3加氢催化剂表面容易发生自发单层分散,有效提高3,3,5-三甲基环己酮外消旋体加氢拆分产物的ee值。在(L)-脯氨酸单层分散的Pd/Al2O3催化剂上,反应温度为40℃、压力为1 MPa、反应时间为10 h时,3,3,5-三甲基环己酮外消旋体加氢拆分产物的ee值达到100%。

Chiral ionic liquids as chiral selectors for separation of tryptophan enantiomers by ligand exchange chromatography

Chiral ionic liquids (CILs) containing imidazolium cations and L-Proline (L-Pro) anions were applied as chiral selector to separate tryptophan (Trp) enantiomers on a C18 column by ligand exchange chromatography. Several factors influencing Trp enantiomers separation, such as alkyl chain length of CILs, concentrations of Cu2+ and CILs, pH of the mobile phase, flow rate, organic solvent and temperature, were studied. Under the optimal conditions, the Trp enantiomers could be successfully separated within 21 min with the resolution of 2.30. At the same time, some thermodynamical parameters were obtained. The experimental results show that the enthalpy values of the Trp enantiomers are negative, indicating that the separation process is exothermic. And the enthalpy values of D-Trp are larger than those of L-Trp, which indicates that L-Trp could form more stable ternary complexes with tryptophan enantiomers.

Synthesis of chiral spirocyclo-quaternary ammonium salts from L-proline and their application as phase-transfer catalysts in asymmetric alkylation

A new series of chiral phase-transfer catalysts 7a-7h were designed and synthesized from L-proline with moderate to good yields.＇The catalytic activity of 7a-Th for the asymmetric alkylation of glycine Schiff bases was evaluated, and some interesting relationships between structure and catalytic activity were revealed.

A new facile approach to N-alkylpyrroles from direct redox reaction of 4-hydroxy-L-proline with aldehydes

An unprecedented acetic acid-catalyzed efficient access to N-alkylpyrroles from reaction of 4-hydroxy-L-proline with a variety of aldehydes has been achieved in good to excellent yields under mild reaction conditions.

霍山石斛内生真菌Fusarium lactis次生代谢产物研究

目的研究霍山石斛内生真菌Fusarium lactis的次生代谢产物。方法利用硅胶、Sephadex LH-20、反相、中压、高效液相制备等多种色谱法分离纯化,根据波谱方法对化合物进行结构鉴定。结果从霍山石斛内生真菌Fusarium lactis中分离得到21个化合物,分别鉴定为N-苯乙基乙酰胺(1)、1H-indole-3-carbaldehyde(2)、胸腺嘧啶(3)、尿嘧啶(4)、lignoren(5)、尿嘧啶核苷(6)、己六醇(7)、腺嘌呤核苷(8)、环-甘氨酸-(L)-脯氨酸(9)、环(D)-脯氨酸-(L)-苯丙氨酸(10)、环(L)-脯氨酸-(L)-苯丙氨酸(11)、2-pyrrolidinone(12)、N-methyl-2-pyrolidinone(13)、环(L)-4-羟基-脯氨酸-(L)-苯丙氨酸(14)、brevianamide F(15)、3-甲基哌嗪-2,5-二酮(16)、7,8-dimethylbenzo[g]pteridine-2,4(1H,3H)-dione(17),环(L)-酪氨酸-(L)-苯丙氨酸(18)、啤酒甾醇(19)、大豆黄素(20)、赤藓糖醇(21)。结论所有化合物均为首次从霍山石斛内生真菌Fusariumlactis中分离得到。

多尼培南的新合成路线

目的:改进多尼培南的制备工艺。方法:以(L)-4-羟基脯氨酸为起始原料,用苄氧羰基氯(CbzCl)做侧链保护试剂,通过9步反应制得多尼培南。结果与结论:目标产物结构经1H-NMR、13C-NMR和LC-MS确证。改进后的制备工艺路线操作简便,成本低,适宜工业化生产。