- Light-enabled synthesis of anhydrides and amides
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Recently, we have demonstrated that the photogeneration of Vilsmeier-Haack reagents is possible using only dimethylformamide (DMF) and tetrabromomethane (CBr4) in the bromination of alcohols. Extending these findings to carboxylic acid substrates has produced a mild and facile approach to the in situ formation of symmetric anhydrides, which were conveniently converted to amide derivatives in a one-pot process. The efficient protocols discussed herein are marked by use of UVA LEDs (365 nm), which have reduced the reaction times and come with a low setup cost.
- Mccallum, Terry,Barriault, Louis
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p. 2874 - 2878
(2015/03/30)
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- Carboxylic acid anhydrides via Pd-catalyzed carbonylation of aryl halides at atmospheric CO pressure
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A convenient method has been developed, which allows for the direct transformation of aryl iodides into the corresponding carboxylic acid anhydrides via Pd-catalyzed carbonylation under atmospheric CO pressure. The Royal Society of Chemistry 2012.
- Li, Yang,Xue, Dong,Wang, Chao,Liu, Zhao-Tie,Xiao, Jianliang
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supporting information; experimental part
p. 1320 - 1322
(2012/02/04)
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- A Cheap, Simple and Efficient Method for the Preparation of Symmetrical Carboxylic Acid Anhydrides
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A manipulatively simple and facile one-pot procedure for the synthesis of symmetrical anhydride is reported. Treatment of carboxylic acids with tosyl chloride in K2CO3 media under solvent free conditions gives the corresponding anhydrides in good to excellent yields in a short reaction time via carboxylic sulfonic anhydride as the key intermediate.
- Kazemi, Foad,Sharghi, Hashem,Nasseri, Mohammad Ali
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p. 205 - 207
(2007/10/03)
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- Reactivity of diacyloxyiodobenzenes toward trivalent phosphorus nucleophiles
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The reaction of diacyloxyiodobenzenes and tetravalent phosphorus nucleophiles was investigated. It was established that both H-phosphonates and secondary phosphine oxides react with diacetoxyiodobenzene in alcohols in the presence of sodium alcoholates yi
- Makowiec, Slawomir,Rachon, Janusz
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p. 352 - 359
(2007/10/03)
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- A thermal fragmentation of 1,2,4-oxadiazole-4-oxides to nitriles and nitrosocarbonyls
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1,2,4-Oxadiazole-4-oxides undergo clean thermal cleavage in refluxing chlorobenzene or xylene to nitriles and nitrosocarbonyl intermediates, which are either trapped with suitable olefins to afford ene adducts or dimerize and rearrange to anhydrides. (C) 2000 Elsevier Science Ltd.
- Quadrelli,Campari,Mella,Caramella
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p. 2019 - 2022
(2007/10/03)
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- The mild oxidation of nitrile oxides affords a convenient entry to nitrosocarbonyl intermediates, versatile tools in organic syntheses
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Nitrile oxides are oxidized by tertiary amine N-oxides in different solvents at room temperature to afford in the presence of dienes nitrosocarbonyl adducts in fair yields. The mild conditions used in oxidizing a variety of nitrile oxides promise a wide application of this method in synthetic processes.
- Quadrelli,Mella,Gamba Invernizzi,Caramella
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p. 10497 - 10510
(2007/10/03)
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- PREPARATION D'ANHYDRIDES A PARTIR D'ACIDES CARBOXYLIQUES ET DE TETRACYANOETHYLENE
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Symmetrical anhydrides are easily obtained at 20-80 deg C, with good yields, by action of tetracyanoethylene on organic carboxylic acids in benzene solutions containing a heteroaromatic nitrogen base or another base.
- Voisin, Daniel,Gastambide, Bernard
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p. 1503 - 1504
(2007/10/02)
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- A Simple and Mild Esterification Method for Carboxylic Acids Using Mixed Carboxylic-Carbonic Anhydrides
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A simple and mild esterification method using mixed carboxylic-carbonic anhydrides has been developed.Simple aliphatic carboxylic esters are prepared in high yields by the reaction of acids with equimolar amounts of chloroformates (2,2,2-trichloroethyl chloroformate is an exception) and triethylamine in the presence of a catalytic amount of 4-(dimethylamino)pyridine.Although aromatic acids give a mixture of the ester, the acid anhydride, and the carbonate under normal conditions utilized in this study, it is found that increasing the amount of 4-(dimethylamino)pyridine drastically decreases the formation of the acid anhydride and the carbonate, affording a satisfactory yield of the ester.This method reaches a limit with sterically hindered acids and the formation of the acid anhydride and the carbonate is favored.
- Kim, Sunggak,Lee, Jae In,Kim, Youn Chul
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p. 560 - 565
(2007/10/02)
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- ACTIVATION OF CARBOXYL GROUPS BY DIPHENYL 2-OXO-3-OXAZOLINYLPHOSPHONATE. FACILE PREPARATION OF VERSATILE REAGENTS, 3-ACYL-2-OXAZOLONES
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Synthetic utility of the 2-oxazolone moiety as an excellent new leaving group is described.Based on such a function of the heterocycles, diphenyl 2-oxo-3-oxazolinylphosphonate has been newly introduced as a carboxyl-activating reagent which permits a facile direct preparation of 3-acyl-2-oxazolones and amides including peptides from a wide variety of carboxylic acids.The 3-acyl-2-oxazolides also serve as versatile reactive agents for highly chemoselective acyl-transfer to the nucleophilic species such as amines, alcohols and thiols, providing convenient and high-yield routes to amides, esters and thiol esters under mild conditions.They are also useful intermediates for ketones and alcohols.
- Kunieda, Takehisa,Higuchi, Tsunehiko,Abe, Yoshihiro,Hirobe, Masaaki
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p. 3253 - 3260
(2007/10/02)
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- A NEW CONVENIENT METHOD FOR THE ESTERIFICATION OF CARBOXYLIC ACIDS
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Reaction of carboxylic acids with equimolar amounts of alkyl chloroformate and triethylamine in the presence of a catalytic amount of 4-dimethylaminopyridine affords the corresponding esters in high yields without the formation of the symmetrical anhydride in most carboxylic acids.
- Kim, Sunggak,Kim, Youn Chul,Lee, Jae In
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p. 3365 - 3368
(2007/10/02)
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