Acid Amide from ester

Carboxylic acid amides from esters COOR CON<... 

Write out the mechanism for this transformation. Hint the reactions are virtually identical to those shown for carboxylic acid amides from esters in Section 20.6. 

No pyrimidine is formed in the absence of the above catalyst. Also N-subst carboxylic acid amides from esters s. N. Nakamizo, Bull. Chem. Soc. Japan 44, 2006 (1971). 

Other Applications. Hydroxylamine-O-sulfonic acid [2950-43-8] h.2is many applications in the area of organic synthesis. The use of this material for organic transformations has been thoroughly reviewed (125,126). The preparation of the acid involves the reaction of hydroxjlamine [5470-11-1] with oleum in the presence of ammonium sulfate [7783-20-2] (127). The acid has found appHcation in the preparation of hydra2ines from amines, aUphatic amines from activated methylene compounds, aromatic amines from activated aromatic compounds, amides from esters, and oximes. It is also an important reagent in reductive deamination and specialty nitrile production. 

Methacrylonitrile (1) differs from 2 only in that it has a methyl (CH3) group on the a-carbon atom. It too is widely used in the preparation of homopolymers and copolymers, elastomers, and plastics and as a chemical intermediate in the preparation of acids, amides, amines, esters, and other nitriles. In a study conducted by the NTP in which 1 was administered orally to mice for 2 years, there was no evidence that it caused cancer, although other less serious toxic effects were noted [27]. Because 1 does not cause cancer, but undergoes many of the same nucleophilic addition reactions as 2 at the (3-carbon, it is sometimes used as a safer commercial replacement for 2, such as in the manufacture of an acrylonitrile-butadiene-styrene-like polymer that provides improved barrier properties to gases such as carbon dioxide in carbonated beverage containers. 

Other Applications. Hydroxylainine-O-sulfonic acid has many applications in the area of organic synthesis. The acid has found application in the preparation of hydrazines from amines, aliphatic amines from activated methylene compounds, aromatic amines from activated aromatic compounds, amides from esters, and oximes. 

Finally, libraries aimed to chiral resolution of racemates will be covered here in particular, the use of chiral stationary phases (CSPs) has recently been reported for the identification of materials to be used for chiral separation of racemates by HPLC. The group of Frechet reported the selection of two macroporous poly methacrylate-supported 4-aryl-1,4-dihydropyrimidines (DHPs) as CSPs for the separation of amino acid, anti-inflammatory drugs, and DHP racemates from an 140-member discrete DHP library (214,215) as well as a deconvolutive approach for the identification of the best selector phase from a 36-member pool library of macroporous polymethacrylate-grafted amino acid anilides (216,217). Welch and co-workers (218,219) reported the selection of the best CSP for the separation of a racemic amino acid amide from a 50-member discrete dipeptide iV-3,5-dinitrobenzoyl amide hbrary and the follow-up, focused 71-member library (220). Wang and Li (221) reported the synthesis and the Circular Dichroism- (CD) based screening of a 16-member library of CSPs for the HPLC resolution of a leucine ester. Welch et al. recentiy reviewed the field of combinatorial libraries for the discovery of novel CSPs (222). Dyer et al. (223) reported an automated synthetic and screening procedure based on Differential Scanning Calorimetry (DSC) for the selection of chiral diastereomeric salts to resolve racemic mixtures by crystallization. Clark Still rejxrrted another example which is discussed in detail in Section 9.5.4. 

The a-chloro-a-sultinyl ketone 20 was prepared from methyl benzoate and chloromethyl phenyl sulfoxide 19 after in situ a-lithiation. Compound 20 is dimetallated by KH and f-BuLi to give the keto dianion 21, which is converted into a potassium/lithium ynolate 22 (equation 7). The resulting metal ynolates are converted into thioesters, carboxylic acids, amides and esters (Section V). 

Carboxylic acid amides from nitriles via imino ester hydrochlorides... 

Aminocarboxylic acid amides from halogenocarboxylic acid esters... 

A sigruficant use is as a catalyst in a multitude of reactions, such as the formation of acrjdic and methacrjdic acid amides from fatty acid amides (81) of cychc ketones such as 4-phen5icyclopentane-l,2-dione and 2,5-dihydroxy-/)-benzoquinone from benzaldehyde diethji acetal and 2,4-dioxo-5,5-dimethoxy-hexanoic acid methyl ester (82) of dimer aldehydes from propane (83) and for the polymerization of epoxy compounds (84). Mag nesium Kthylate. Magnesium ethoxide [2414-98-4]y Mg(OC2H 2 niol wt 114.4, is an almost white hygroscopic powder density,... 

The formation of amides from ammonium salts of oxygen acids is in fact only a part of the dissociation of the intermediate addition compound in amide formation from an amine and an acid. The formation of amide from ester and ammonia is similar to the formation of amide from... 

Sodium salt (s. a. under Phosphonitrile chloride) N-Acylsulfonic acid amides from active carboxylic acid esters... 

Subst. carboxylic acid amides from inactive carboxylic acid esters Concerted acid-base catalysis... 

The Lewis base most used for amide formation is DBU. This amidine made it possible to obtain amides from esters or aetivated acids. DBU is also responsible for catalysing the eyanoaeylation of ketones with acyl cyanides. Synthesis of methyl esters will be deseribed in the section on methylation reactions (Section 2.1.9). 

Boric acid esters/p-toluenesulfonic acid Carboxylic acid amides from carboxylic acids... 

Carboxylic acid amides from carboxylic acid esters COOR CON <... 

Startg. a-diloroglycidic ester deriv. allowed to react at 0-35° with a slight excess of dimethylamine in pentane, -aminopyruvic acid deriv. Y 74%. F. e., also with simultaneous formation of amides from esters, s. J. Villieras, N. Ferracutti, and J.-C. Combret, C. r. 270 (C), 2083 (1970). 

Malonic acid amides from malonic acid esters G(GOOR)2 G(GONH2)2... 

Dihydro-l,4-oxazin-2-ones and a-ketocarboxylic acid amides from a-ketocarboxylic acid esters... 

Radical substitution of the hydrogen from the methyl groups PHj OH,X Kl( -HY CH3 X CH, hc=ch X-Y = Br-Br,C1-C1 (12) RS0.-C1 (13) I 1 ( ) Halogenation, sulfonation, binding of maleric anhydride group, unsaturated carboxyl acids, amides, imides, esters, epoxides, amines, alcohol can be used Product of (12) is precursor for PCMs, that of (13) for direct PCMs. 

Hydrogen chloride Quinoline-4-carhoxylic acid amides from isatins and enamines Dicarhoxylic acid imides from dicarhoxylic acid amide esters... 

But now the question is how do we make amides from esters Esters are less reactive than acid halides or anhydrides. So, we have to use some kind of trick to coax the reaction along. We cannot use acid or base (an acid would just protonate the attacking atnine, rendering it useless and a base would cause other side reactions that we will learn in the next chapter). Instead, we use brute force and patience. We just heat the reaction for a long time, and a reaction is observed, which can occur via the following mechanism ... 

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