- The thermal amidation of carboxylic acids revisited
-
Factors affecting the thermal condensation of carboxylic acids with amines have been investigated, and an effective protocol for this waste-minimized, environmentally benign transformation has been identified. Fourteen examples demonstrate the applicability of this procedure to aliphatic, aromatic and heteroaromatic carboxylic acids and primary and secondary aliphatic as well as aromatic amines. The approach leads to the corresponding amides in good yields. Georg Thieme Verlag Stuttgart.
- Goossen, Lukas J.,Ohlmann, Dominik M.,Lange, Paul P.
-
-
Read Online
- Synthetic method for preparing amide compounds through co-catalysis of niobium pentachloride and ionic liquid
-
The invention relates to a synthetic method for preparing amide compounds through co-catalysis of niobium pentachloride and ionic liquid. The preparation method is characterized by comprising the following steps: weighing organic carboxylic acid, organic amine, niobium pentachloride, ionic liquid and a molecular sieve, adding the materials into a reactor, adding an organic solvent, and reacting for 6-24 hours at the reaction temperature of 70-110 DEG C to obtain a corresponding amide product. The molar ratio of the organic carboxylic acid to the organic amine to the niobium pentachloride to the ionic liquid is 1:(1-3):(0.01-1):(0.05-1); wherein the mass ratio of the organic carboxylic acid to the molecular sieve is 1: (0.2-1). According to the method, the substrate range is expanded, the reaction yield is high (95% or above), the catalyst dosage is small, the atom economy is high, the catalyst is cheap and easy to obtain, the production cost can be greatly reduced, and the method is suitable for industrial production.
- -
-
Paragraph 0044-0046
(2020/07/13)
-
- 2,2-Diazido-1,2-diarylethanones: Synthesis and Reactivity with Primary Amines
-
We describe the synthesis and reactivity of a new class of diazidated compounds: the 2,2-diazido-1,2-diarylethanones. The diazides are easily accessible from 1,2-diarylethanones through a mild and simple protocol for the direct oxidative diazidation, using iodine and sodium azide in DMSO at room temperature. In studies towards their reactivity with amine nucleophiles under basic conditions, the diazides are shown to undergo a controlled fragmentation reaction that provides a straightforward access to the corresponding amides. In stark contrast to our previous results on the amine-triggered fragmentation of diazidated compounds, aromatic nitriles are found to be by-products of synthetic value. The net reaction consisting of diazidation and subsequent fragmentation, thus, provides a simple way to convert 1,2-diarylethanones into both aromatic amides and nitriles.
- Holzschneider, Kristina,H?ring, Andreas P.,Kirsch, Stefan F.
-
p. 2824 - 2831
(2019/04/30)
-
- Water-Tolerant and Atom Economical Amide Bond Formation by Metal-Substituted Polyoxometalate Catalysts
-
A simple, safe, and inexpensive amide bond formation directly from nonactivated carboxylic acids and free amines is presented in this work. Readily available Zr(IV)- and Hf(IV)-substituted polyoxometalates (POM) are shown to be catalysts for the amide bond formation reaction under mild conditions, low catalyst loading, and without the use of water scavengers, dry solvents, additives for facilitating the amine attack, or specialized experimental setups commonly employed to remove water. Detailed mechanistic investigations revealed the key role of POM scaffolds which act as inorganic ligands to protect Zr(IV) and Hf(IV) Lewis acidic metals against hydrolysis and preserve their catalytic activity in amide bond formation reactions. The catalysts are compatible with a range of functional groups and heterocycles useful for medicinal, agrochemical, and material chemists. The robustness of the Lewis acid-POM complexes is further supported by the catalyst reuse without loss of activity. This prolific combination of Zr(IV)/Hf(IV) and POMs inaugurates a powerful class of catalysts for the amide bond formation, which overcomes key limitations of previously established Zr(IV)/Hf(IV) salts and boron-based catalysts.
- De Azambuja, Francisco,Parac-Vogt, Tatjana N.
-
p. 10245 - 10252
(2019/11/03)
-
- Pathways in the Degradation of Geminal Diazides
-
The degradation of geminal diazides is described. We show that diazido acetates are converted into tetrazoles through the treatment with bases. The reaction of dichloro ketones with azide anions provides acyl azides, through in situ formation of diazido ketones. We present experimental and theoretical evidence that both fragmentations may involve the generation of acyl cyanide intermediates. The controlled degradation of terminal alkynes into amides (by loss of one carbon) or ureas (by loss of two carbons) is also shown.
- Holzschneider, Kristina,H?ring, Andreas P.,Haack, Alexander,Corey, Daniel J.,Benter, Thorsten,Kirsch, Stefan F.
-
p. 8242 - 8250
(2017/08/14)
-
- A One-Pot, fast, and efficient amidation of carboxylic acids, α-amino acids and sulfonic acids using pph3/n-chlorobenzotriazole system
-
Triphenylphosphine (PPh3)/N-chlorobenzotriazole (NCBT), and amine (primary and secondary aliphatic amines and also substituted anilines) in CH2Cl2 efficiently converted carboxylic acids, α-amino acids, and sulfonic acids to the corresponding amides and sulfonamides at room temperature. Good to excellent yields, inexpensive, and fast reaction conditions are the important features of this procedure.
- Rouhi-Saadabad, Hamed,Akhlaghinia, Batool
-
p. 1703 - 1714
(2015/09/15)
-
- Palladium-catalyzed fluorocarbonylation using N-formylsaccharin as CO source: General access to carboxylic acid derivatives
-
N-Formylsaccharin, an easily accessible crystalline compound, has been employed as an efficient CO source in Pd-catalyzed fluorocarbonylation of aryl halides to afford the corresponding acyl fluorides in high yields. The reactions use a near-stoichiometric amount of the CO source (1.2 equiv) and tolerate diverse functional groups. The acyl fluorides obtained could be readily transformed into various carboxylic acid derivatives such as carboxylic acid, esters, thioesters, and amides in a one-pot procedure.
- Ueda, Tsuyoshi,Konishi, Hideyuki,Manabe, Kei
-
supporting information
p. 5370 - 5373
(2013/11/06)
-
- Mo(CO)6-mediated carbamoylation of aryl halides
-
A simple method for the synthesis of amides has been developed by molybdenum-mediated carbamoylation of aryl halides. Whereas the conventional palladium-catalyzed three-component coupling reaction requires a large excess of gaseous carbon monoxide, the incorporation of carbon monoxide in this Mo-mediated carbamoylation reaction is so efficient that it requires only a slight excess amount of carbon monoxide in the form of its molybdenum complex, Mo(CO)6. The reaction is applicable for the synthesis of a wide variety of not only secondary and tertiary amides but also primary amides by using aqueous ammonia.
- Ren, Wei,Yamane, Motoki
-
experimental part
p. 8410 - 8415
(2011/02/23)
-
- Molybdenum-mediated carbonylation of aryl halides with nucleophiles using microwave irradiation
-
Figure Presented. A new, efficient, and practical molybdenum-mediated carbonylation of aryl and heteroaryl halides with a variety of nucleophiles is described using microwave irradiation. A range of reactions illustrating the wide scope of this chemistry were carried out and proceeded in good to excellent yields.
- Roberts, Bryan,Liptrot, David,Alcaraz, Lilian,Luker, Tim,Stocks, Michael J.
-
supporting information; experimental part
p. 4280 - 4283
(2010/11/04)
-
- Carbamoylation of aryl halides by molybdenum or tungsten carbonyl amine complexes
-
When aryl halide is treated with molybdenum carbonyl amine complex in the presence of base, carbamoylation proceeds to give amide in good yield. The proposed mechanism involves oxidative addition of aryl halide to molybdenum(0) complex, migratory insertio
- Ren, Wei,Yamane, Motoki
-
supporting information; experimental part
p. 3017 - 3020
(2010/07/05)
-
- Palladium-catalyzed carbamoylation of aryl halides by tungsten carbonyl amine complex
-
(Chemical Equation Presented) In the presence of aminepentacarbonyltungsten, base, and a catalytic amount of palladium(0) complex, carbamoylation of aryl halide proceeds to afford amide. The reaction may involve transmetalation between palladium(II) inter
- Wei, Ren,Yamane, Motoki
-
supporting information; experimental part
p. 8332 - 8335
(2010/02/17)
-