Dimethyl Sulfoxide Pivaloyl Chloride: A New Reagent for Oxidation of Alcohols to Carbonyls

An efficient procedure for conversion of alcohols to the corresponding carbonyl compounds, an alternative to the classical Swern oxidation, is described. Pivaloyl chloride is employed as a mild and inexpensive electrophile. A possible reaction mechanism is proposed.     

Synthesis of Carbonyl Compounds from Alcohols Using Electrochemically Generated Superoxide Ions in RTILs

Abstract

We show that the superoxide ion (O₂ ^??) generated electrochemically from oxygen dissolved in room-temperature ionic liquids (RTILs) reacts with primary and secondary alcohols to form the corresponding ketones and carboxylic acids, respectively. Specifically, we study the conversion of benzhydrol to benzophenone and benzyl alcohol to benzaldehyde/benzoic acid. The kinetics (e.g., rate, selectivity, and yield) for these reactions are also determined as functions of the variations in the structure of the ionic liquids. The RTILs used here are imidazolium-based cations where the functional groups on the imidazolium ring are modified. Specifically, 1-butyl-3-methylimidazolium hexafluorophosphate [bmim][PF₆], 1-butyl-2,3-dimethylimidazolium hexafluorophosphate [bdmim][PF₆], and 1-hexyl-3-methylimidazolium hexafluorophosphate [hmim][PF₆] are used as the reaction medium. These results are compared to an ammonium-based RTIL (N-butyl-N-trimethylammonium bis(trifluoromethylsulfonyl)imide). The results show that the nucleophilic attack by the O₂ ^?? of both the RTIL and the alcohol, especially that of the H atom at the R2 position of the [bmim][PF₆] and [hmim][PF₆], greatly affects the yields. No RTIL degradation products were detected for the reactions in [bdmim][PF₆] and N-butyl-N-trimethylammonium bis(trifluoromethylsulfonyl)imide ionic liquids. For the benzyl alcohol oxidation reaction in the RTIL, N-butyl-N-trimethylammonium bis(trifluoromethylsulfonyl)imide, benzaldehyde formed did not undergo further oxidation to form benzoic acid, which may be due to the greater hydrophobicity of this RTIL. The competitive reaction kinetics between the alcohol and RTIL component must be considered in the selection of the RTIL solvent system.     

Catalytic Disproportionation of the Superoxide Intermediate from Electrochemical O2 Reduction in Nonaqueous Electrolytes

Tris(pentafluorophenyl)borane (TPFPB) was found to be an efficient catalyst for rapid superoxide (O₂^?) disproportionation. The kinetics for the catalytic disproportionation reaction is much faster than the reaction between O₂^? and propylene carbonate. Therefore, the negative impact of the reaction between the electrolyte and O₂^? produced by the O₂ reduction is minimized. The cathodic current for O₂ reduction can be doubled in the presence of TPFPB. The high reduction current resulted from the pseudo two‐electron O₂‐reduction reaction due to the replenishment of O₂ at the electrode surface. This discovery could lead to a new avenue for the development of high‐capacity, high‐rate, rechargeable Li–air batteries.     

Tetrachlorosilane-Zinc Chloride as a New Potent Binary Reagent for One-Pot,Three-Component Synthesis of Mannich-Type Products

A combination of tetrachlorosilane and zinc chloride in dichloromethane as an efficient and ambient binary reagent to promote a one-pot amidoalkylation reaction of enolizable ketones, aromatic aldehydes with acetonitriles, or benzonitrile have been developed. The newly synthesized β-acetamidoketones 3 and β-benzamidoketones 5 were obtained in good yields.     

废水处理新试剂——絮凝剂

高分子絮凝剂在水处理技术中占有十分重要的地位,而且已成为目前废水处理中的一类不可缺少的重要试剂。本文介绍了高分子絮凝剂的絮凝机理、种类、性质及其应用。     

用新中间体合成头孢曲松钠

以二乙基硫代磷酰-（Z）-（2-氨基噻唑4-基）-甲氧酰胺-乙酸钠盐为中间体合成了头孢曲松钠,收率94．77％。保存2年后头孢曲松钠的含量平均下降0．4％,色级平均下降0．5号,质量稳定性较好。     

Silica Chloride as a Mild and Efficient Reagent for Acetylation of Alcohols

A variety of alcohols underwent acetylation with acetic anhydride in the presence of silica chloride. All reactions were performed at room temperature and under completely heterogeneous conditions in good to high yields.

     

Silicon-Free SuFEx Reactions of Sulfonimidoyl Fluorides: Scope,Enantioselectivity, and Mechanism

SuFEx reactions, in which an S−F moiety reacts with a silyl-protected phenol, have been developed as powerful click reactions. In the current paper we open up the potential of SuFEx reactions as enantioselective reactions, analyze the role of Si and outline the mechanism of this reaction. As a result, fast, high-yielding, “Si-free” and enantiospecific SuFEx reactions of sulfonimidoyl fluorides have been developed, and their mechanism shown, by both experimental and theoretical methods, to yield chiral products.     

Fenton Reagent Generated in Electrolysis Cell and Its Usage in Degradation and Decolorization of Dyes

IntroductionAs is known,textile wastewater is a troubleindustrial wastewater due to its environment pollu-tion caused by its deep color,huge amounts,highCODcrand BOD5,as well as itsdifficultdegradationby biodegradation[1— 3 ] .Fenton reagent[4— 6] has a high redox potential,2 .8V. Recently,the Fenton reagent used as anoxidant to treat toxic organic wastewater such aswood glue,lead trinitroresorcinate and textilewastewater has been reported.Although hydroxylradical can be generated by a c…     

Quinolinium Bromochromate-A New Reagent for Bromination and Oxidation

The new reagent, quinolinium bromochromate (QBC), apart from being efficient as an oxidant for alcohols, also functions as a good brominating agent for aromatic compounds.     

Benzimidazolium Bromochromate-A New Reagent for Bromination and Oxidation

The new reagent, benzimidazolium bromochromate (BIBC), apart from being efficient as an oxidant for alcohols, also functions as a good brominating agent for aromatic compounds.     

Preparation and Acylation of a New Biotinylation Reagent

Biotinylamidopropylammonium trifluoroacetate was obtained by acylation of 4-(tert-butyloxycarbonylamino)propylamine, followed by removal of the protective group. Consequently, it was found to be useful for the development of effective immunoassays.     

N-Methylpiperidinium Chlorochromate Adsorbed on Alumina: A New Deoximation Reagent

Summary.  N-Methylpiperidinium chlorochromate adsorbed on alumina was found to be an efficient and selective reagent for the mild oxidative cleavage of oximes. Received March 1, 2001. Accepted March 22, 2001     

N-Methylpiperidinium Chlorochromate Adsorbed on Alumina: A New Deoximation Reagent

 N-Methylpiperidinium chlorochromate adsorbed on alumina was found to be an efficient and selective reagent for the mild oxidative cleavage of oximes.     

Hydrozirconation: A New Transition Metal Reagent for Organic Synthesis

Hydrozirconation has recently been developed as a procedure for functionalizing alkenes, alkynes, and 1,3-dienes via organozirconium(IV) intermediates. These intermediates react with a variety of electrophilic reagents to give organic products in high yield. Mechanisms of reactions involved in these sequences are discussed.     

新荧光试剂4-氨基安替比林芳香席夫碱的合成

新荧光试剂4-氨基安替比林芳香席夫碱的合成