Esters amides from

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. 

Preparation op Amides from Esters by Aminolysis with Dimethyl-... 

AMIDES FROM ESTERS WITH DIMETHYLALUMINUM AMIDES... 

A New General Method for the Preparation of Weinreb Amides from Esters... 

Table 3.3 Preparation of Weinreb amides from esters.

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. 

The formation of amides from esters appears to be a closely related process.17 Here we may suppose that the reaction proceeds similarly through an amide ion ... 

Amides from Esters Hydrolysis of Ureides Hydrolysis of Carbamates Hydrolysis of Carboxamides Decarboxylation ... 

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... 

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). 

Table 1.10 Synthesis of amides from esters and amines catalyzed by complex...

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). 

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. 

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 ... 

In the second group we consider interconversions of functional groups with the exchange of hetereoatoms, breaking of old and formation of new C-heteroatom bonds. Examples of these transformations are interconversion of an amide to ester, thioketone to ketone or alkylhalide to alcohol. They are related to S5mthetic reactions formation of amide from ester, thioketone from ketone or haloalkane from alcohol. Characteristic of all the above interconversions is the disconnection (imaginative process ) of the C-heteroatom bond, C-N or C-O. In the synthetic direction C-N, C-S and C-Hal bonds are formed. Therefore, such FGIs are also denoted as DIS-C-X, where X stands for heteroatom. 

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). 

Amines may also be prepared by conversion of esters into amides followed by reduction. See section 83 (Amides from Esters) and section 95 (Amines from Amides)... 

An interesting aspect of this reaction was reported by Movassaghi, who found that the preparation of amides from esters, expected to be possible under similar conditions, failed except for the special case of 1,2-amino alcohols. Similar procedures were also found to promote O- to C-carboxyl transfer reactions of oxazolyl carbonates (Scheme 14.4). " ... 

Although selenolsubtilisin is essentially inactive in cleaving amides, it could still be useful as a ligase for preparing amides from esters and amines. In such a scheme the modified enzyme would be acylated with an activated ester and subsequently transfer its acyl group to a suitable nucleophile. However, efficient amide bond formation will require high selectivity for aminolysis with respect to hydrolysis of the... 

Schwaebe M, Ryckman D, Nagasawa J, Pierre F, Vialettes A, Haddach M (2011) FacQe and efficient generation of quinolone amides from esters using aluminum chloride. Tetrahedron Lett 52 1096-1100... 

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