反相高效液相色谱分析克拉霉素合成工艺中区域选择性甲基化的关键中间体

采用反相高效液相色谱法对克拉霉素合成工艺中关键中间体E-2′,4″-双(三甲基硅)-红霉素A-9-(1-异丙氧环己基)肟、Z-2′,4″-双(三甲基硅)-红霉素A-9-(1-异丙氧环己基)肟和E-2′,4″-双(三甲基硅)-6-甲基红霉素A-9-(1-异丙氧环己基)肟、Z-2′,4″-双(三甲基硅)- 6-甲基红霉素A-9-(1-异丙氧环己基)肟及其相关的6种工艺杂质进行了分离、定性和定量分析。色谱柱为DIKMA公司的Inertsil ODS-3(150 mm×4.6 mm i.d., 5 μm);流动相     

Transformation of steroidal cyclohexadienyl anion without fragmentation: Unexpected synthesis of methylenesteroid

In contrast with androsta-1,4-diene-3α/β, 17β-diol, its 3-O-methyl ether is transformed upon C(3)-deprotonation into the corresponding 3-methylene steroid with migration of theO-methyl group on the steroid skeleton (by the scheme of Wittig rearrangement) rather than eliminating the 19-methyl group. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1393–1395, July, 1999.     

红霉素肟羟基的醚化保护

用3种双烷氧基环乙烷对红霉素肟的肟羟基加以保护,实验发现,1,1－二异丙氧基环己烷和1,1－二乙氧基环己烷的效果比较好,工艺条件为二氯甲烷作溶剂,盐酸吡啶作催化剂,反应温度40度,反应时间前者、1h,后者7h。     

杂芳基烷基醚、杂芳基卤化物与(氘代)醇的亲核醚化

研究了在叔丁醇钾的作用下,杂芳基烷氧化合物、杂芳基卤化物和杂芳基硫醚与各种伯、仲、叔脂肪醇高效醚化,强调了天然产物和生物活性分子的衍生化以及不易通过其他途径获得的氘代芳基烷基醚的合成方法的实用性.     

Total Synthesis and Structure Revision of Halioxepine

The first total synthesis of halioxepine is accomplished using a 1,4-addition for constructing the quaternary center at C10 and a halo etherification for the generation of the tertiary ether at C7. The correct structure of halioxepine was determined by assembling different enantiomeric building blocks and by changing the relative configuration between C10 and C15.     

镧改性β分子筛的制备及催化合成ETBE的活性研究

采用离子交换法和浸渍法将稀土元素镧引入到Hβ分子筛中,制备了负载型催化剂x%La/Hβ(x表示镧负载量),通过XRD、FT-IR、NH3-TPD、Py-IR等考察了镧对Hβ分子筛结构及表面酸性的影响.结果表明,两种方法负载镧后Hβ分子筛的骨架结构没有变化,但结晶度都明显降低;两种方法都使得Hβ分子筛的B酸量增加,而交换法增加较多.将其用于乙醇和叔丁醇为原料合成乙基叔丁基醚(ETBE)的反应,结果发现,交换法负载镧后Hβ分子筛的催化活性较高,而浸渍法负载镧后Hβ分子筛的活性较低.说明B酸量的增加有利于此醚化反应的进行.     

Solvent‐Free Williamson Synthesis: An Efficient,Simple, and Convenient Method for Chemoselective Etherification of Phenols and Bisphenols

Etherification of phenols with dimethyl‐ and diethylsulfates and benzyl chloride was performed efficiently in the presence of a suitable solid base, NaHCO₃ or K₂CO₃, under solvent‐free conditions. The reaction proceeded rapidly at low temperature, and the corresponding ethers were obtained with high purity and excellent yield. Selective etherification of electron‐poor phenols in the presence of electron‐rich ones and also selective mono‐etherification of bisphenols are the noteworthy advantages of this method. This method is environmentally friendly.