Mixed Carboxylic Acid Anhydrides Research Articles

Preparation of Potassium Acyltrifluoroborates (KATs) from Carboxylic Acids by Copper-Catalyzed Borylation of Mixed Anhydrides.

We report the preparation of potassium acyltrifluoroborates (KATs) from widely available carboxylic acids. Mixed anhydrides of carboxylic acids were prepared using isobutyl chloroformate and transformed to the corresponding KATs using a commercial copper catalyst, B2 (pin)2 , and aqueous KHF2 . This method allows for the facile preparation of aliphatic, aromatic, and amino acid-derived KATs and is compatible with a variety of functional groups including alkenes, esters, halides, nitriles, and protected amines.

Preparation of Potassium Acyltrifluoroborates (KATs) from Carboxylic Acids by Copper‐Catalyzed Borylation of Mixed Anhydrides**

AbstractWe report the preparation of potassium acyltrifluoroborates (KATs) from widely available carboxylic acids. Mixed anhydrides of carboxylic acids were prepared using isobutyl chloroformate and transformed to the corresponding KATs using a commercial copper catalyst, B2(pin)2, and aqueous KHF2. This method allows for the facile preparation of aliphatic, aromatic, and amino acid‐derived KATs and is compatible with a variety of functional groups including alkenes, esters, halides, nitriles, and protected amines.

ChemInform Abstract: Solid Supported Reactions and Reagents. Part 12. Selective Reduction of Mixed Anhydrides of Carboxylic Acids to Alcohols Using Borohydride Exchange Resin (BER)‐Nickel Acetate.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Selective reduction of mixed anhydrides of carboxylic acids to alcohols using borohydride exchange resin (BER)–nickel acetate

Mixed anhydrides of carboxylic acids have been selectively reduced to alcohols with borohydride exchange resin–nickel acetate under mild conditions and in good yields.

ChemInform Abstract: Nickel Boride Reduction of Symmetric and Mixed Anhydrides of Carboxylic Acids.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Synthesis, characterization, and catalytic properties of polysiloxanes with pendant 4-(3-pyridinyl)butyl and 4-(1-oxypyridin-3-yl)butyl groups

New silane monomers with the pendant 4-(3-pyridine)butyl group have been synthesized by hydrosilation of 3-(3-butenyl)pyridine with Me n Si(OEt)3-n H (n=0, 1) using a platinum catalyst. Only β-addition products were observed. The products were characterized by elemental analysis, infrared,1H- and13C-NMR spectroscopy, and gas chromatography-mass spectrometry. Hydrolysis-polycondensation of the difunctional monomer with a basic catalyst, Me4NOH, gave a mixture of cyclic oligomers, principally cyclic tetramer, and linear homopolymer. Under similar reaction conditions, the trifunctional monomer gave crosslinked material which was soluble in common organic solvents. The linear homopolymer and crosslinked polymer were trimethylsilyl end-blocked with hexamethyldisilazane. The cyclic and end-blocked polymers were characterized by elemental analysis and spectroscopic methods. Molecular weights of the polymers were obtained by end-group analysis using1H-NMR spectral data, size exclusion chromatography, and direct insertion-probe mass spectrometry. The cyclic, linear, and crosslinked materials were N-oxidized withm-chloroperoxybenzoic acid and characterized by spectroscopic methods. The polymeric N-oxide derivatives were shown to be effective transacylation catalysts in the synthesis of mixed carboxylic acid anhydrides in immiscible solvents (H2O/CH2Cl2) under phase-transfer conditions. The implications of the results on the mechanism of catalysis are discussed.

New Synthetic Methods and Reagents for Complex Carbohydrates. II. Synthesis of 2-Acylamino-2-deoxy-d-glucopyranose Derivatives by Dimethylphosphinothioic Mixed Anhydride Method

Abstract Dimethylphosphinothioic (Mpt) mixed anhydrides of carboxylic acids were found to be useful for N-acylation of 2-amino-2-deoxy-d-glucopyranose derivatives without protecting the hydroxyl functions. By this method, N-acylation of 2-amino-2-deoxy-d-glucopyranose hydrochloride in methanol was also found to be possible.

ChemInform Abstract: Reduction of Symmetric and Mixed Anhydrides of Carboxylic Acids by Sodium Borohydride with Dropwise Addition of Methanol.

AbstractThe symmetric anhydrides (I) are reduced with sodium boranate, yielding the alcohols (II), together with the carboxylic acids (III).

Reduction of Symmetric and Mixed Anhydrides of Carboxylic Acids by Sodium Borohydride with Dropwise Addition of Methanol

The symmetric anhydrides (I) are reduced with sodium boranate, yielding the alcohols (II), together with the carboxylic acids (III).

Mixed carboxylic acid anhydrides: V. Synthesis of alkyl formates

AbstractThe investigations into the esterification of primary, secondary and tertiary alcohols with formic acid/acetic anhydride reaction mixtures have been extended. The effect of various molar intake ratios of formic acid and acetic anhydride as well as the influence of temperature, solvents, and catalysts have been examined. The results obtained led to simple methods of synthesis of pure alkyl formates in high yields.

Mixed carboxylic acid anhydrides: II. Esterification of alcohols with the formic acid/acetic anhydride reaction mixture

AbstractThe investigations of Béhal and other authors (loc. cit.) have led to the generally accepted view that the esterification of alcohols with the formic acid/acetic anhydride reaction mixture leads to the exclusive formation of formates. A reinvestigation, however, has shown that under the conditions used by Béhal, acetates are also produced. Generally, the amounts of acetates formed decrease in the order primary, secondary, tertiary alcohols; in the last case acetates are formed to a negligible degree. This finding leads to a simple and convenient method for the preparation of pure tertiary alkyl formates in high yields. The results obtained are discussed in relation to conflicting literature data as regards the synthesis of formates.

Mixed carboxylic acid anhydrides: III. Esterification of phenols with the formic acid/acetic anhydride reaction mixture

AbstractThe reaction of the formic acid/acetic anhydride reaction mixture with phenols at room temperature affords mainly the formates together with acetates. The quantity of acetates formed can be reduced by carrying out the esterification in solutions of benzene, carbon tetrachloride and other solvents. This finding has led to the synthesis of pure aryl formates.