Oxidation of alcohols using clay-supported potassium peroxodiphosphate

Clay-supported potassium peroxodiphosphate efficiently oxidizes benzylic alcohols to the corresponding aldehydes without overoxidation to acids. H₃P₂O_g ⁻ as the active species.     

NaIO_4-Catalyzed Bromination of the Aromatic Ring of Lappaconitine

Lappaconitine 1, a bisnorditerpenoid alkaloid, was isolated from many plants of Aconitum species such as A. barbatum var. pulerulum and A. sinomontanum (Ranunculaceae)1-3, and used clinically for treatment of analgic disease as a nonaddicted drug in China4, and as an antiarrythmic in Uzbekistan5. In order to search for high activity, low toxicity compounds, we have carried out the structure modifications of lappaconitine. In this case, an attempt to induce the oxygenated group at C-10 in 1 b…     

Synthesis of 4,5-dihydroxyphthalonitrile

4,5-Dihydroxyphthalonitrile was synthesized from pyrocatechol in a simple way. The compound obtained is a convenient starting reagent for the preparation of 4,5-dialkoxyphthalonitriles.     

1-(4-乙酰氨基苯基)-α-溴代-1-丙酮的合成

1-(4-乙酰氨基苯基)-α-溴代-1-丙酮(I)是合成强心药物匹莫苯(Pirnobendan)和新型抗抑郁类药物氨基酮的主要中间体,它可以1-(4-乙酰氨基苯基)丙酮(Ⅱ)为原料,通过α位溴代得到。主要方法有：(1)以冰醋酸作溶剂,滴加溴的醋酸溶液反应后,经氯仿萃取,硅胶G柱层析分离得产品。     

Synthesis of Methyl 2‐Methylazulene‐3‐carboxylate in the Presence of Molecular Sieves and Reaction with N‐Bromosuccinimide

The preparation of methyl 2‐methylazulene‐1‐carboxylate (1) was carried out in the presence of molecular sieves to obtain a good yield. The product was subjected to bromination under different reaction conditions to obtain methyl 1‐bromo‐2‐methylazulene‐1‐carboxylate (2) and methyl 1‐bromo‐2‐(bromomethyl) azulene‐1‐carboxylate (3).     

PPh3⋅HBr‐DMSO Mediated Expedient Synthesis of γ‐Substituted β,γ‐Unsaturated α‐Ketomethylthioesters and α‐Bromo Enals: Application to the Synthesis of 2‐Methylsulfanyl‐3(2 H)‐furanones

An efficient chemoselective general procedure for the synthesis of γ‐substituted β,γ‐unsaturated α‐ketomethylthioesters from α,β‐unsaturated ketones has been achieved through an unprecedented PPh₃?HBr‐DMSO mediated oxidative bromination and Kornblum oxidation sequence. The newly developed reagent system serves admirably for the synthesis of α‐bromoenals from enals. Furthermore, AuCl₃‐catalyzed efficient access to 3(2H)‐furanones from the above intermediates under extremely mild conditions are described.     

芳香胺和酚溴化的新工艺

研究了在室温下,N-溴丁二酰亚胺对芳香胺和酚的溴化工艺,在CHCl3、EtOH或EtOH/CHCl3溶剂中,用等摩尔的N-溴丁二酰亚胺可将某些芳香胺和酚(考察了5种反应底物)选择性地一溴化,产率92%~98%,N-溴丁二酰亚胺和反应底物摩尔比为2∶1;某些芳香胺和酚被专一地二溴化(考察了5种反应底物),产率90%~97%。 反应无须催化剂,投料后室温搅拌,反应条件温和,产品只需过滤洗涤即可纯化,操作简便。     

用于催化氧气氧化苄醇到醛的新型且简单的催化体系（溴化铜/TEMPO/哌啶）

构建了一个可用于催化氧气氧化苄醇类醇到醛的新型催化体系(溴化铜/四甲基哌啶氧化物/哌啶).该体系以乙腈为溶剂,可以在50℃下高活性和选择性地催化氧气将含不同取代基的苄醇氧化为相应的醛.然而,该体系对于仲醇、脂肪族伯醇以及烯丙醇类型醇的氧化没有催化活性.     

锰催化苄基C—H键氟化反应机理的理论研究

采用密度泛函理论(Density Functional Theory,DFT),对锰催化剂MnIII(salene)F作用下苄基C—H键氟化反应的机理进行了深入的理论研究.对该反应中涉及到的重要中间体和过渡态的能量、Mulliken电荷分布、前线分子轨道等进行了分析.计算结果表明采用[MnIV(OH)(salene)F...