Amides s. Carboxylic acid

Nitriles are interesting precursors of both amides and carboxylic acids. In vivo there are two pathways for the bioconversion of nitriles to carboxylic acids (Scheme 6.19). In the first method a nitrilase catalyzes the enantioselechve hydrolysis of a racemic or prochiral nitrile. The second pathway involves a two-enzyme cascade in which an aselective nitrile hydratase (NHase) catalyzes the hydration of the racemic nitrile to the racemic amide followed by an amidase-catalyzed enantioselechve hydrolysis to the carboxylic acid. The amidase is generally, but not always, (S)-selechve, resulting in the formahon of a 1 1 mixture of the (S)-acid... 

Blaschke et al. [54—56] synthesized polyacrylamide and polymethacrylamide containing chiral side chains. In order to make CSPs, these polymers were bonded to silica gel chemically [54-56]. The CSP obtained by /V-acrylol-(.S)-phenylalanine ethyl ester was commercialized by Merck Chemical Company by the trade name ChiraSpher. The racemic compounds resolved are those capable of forming hydrogen-bondings (i.e., amides, imides, carboxylic acids, and alcohols). It has been reported that nonpolar solvents like benzene and toluene individually or their mixtures were the best mobile phases. In addition to these CSPs, other amide CSPs were prepared and tested for the chiral resolution [57,58]. 

Sn[N(TMS)2l2, A, A -carbonyldiimidazole (110, p. 1418), which behaves as in reaction 16-63, POCl3, °" TiCl4, ° molecular sieves,Lawesson s reagent (p. 1278), ° and (MeO)2POCl. ° Certain dicarboxylic acids form amides simply on treatment with primary aromatic amines. In these cases, the cyclic anhydride is an intermediate and is the species actually attacked by the amine. Carboxylic acids can also be converted to amides by heating with amides of carboxylic acids (exchange),sulfonic acids, or phosphoric acids, for example, ... 

Carboxylic acid amides from carboxylic acid bromides s. 4, 430 COBr —> CONHs... 

Among the ethers of prolinol, (5)-2-methoxymethylpyrrolidinc [SMP, (S)-10] has found most applications. It is readily prepared from prolinol by the normal sodium hydride/iodo-methane technique9,13 (sec also Section 2.3. for O-alkylations of other amino alcohols) and is also commercially available. An improved synthesis from proline avoids the isolation of intermediates and gives the product (which is highly soluble in water) by continuous extraction14. SMP has been used as the lithium salt in deprotonation and elimination reactions (Section C.) and as an auxiliary for the formation of chiral amides with carboxylic acids, which in turn can undergo carbanionic reactions (Sections D.l.3.1.4., D.l. 1.1.2.. D.l. 1.1.3.1., in the latter experimental procedures for the formation of amides can be found). Other important derivatives are the enamines of SMP which are frequently used for further alkylation reactions via enolates (Sections D.l.1.2.2.. where experimental procedures for the formation of enamines are... 

Kunishima, M. Yoshimura, K. Morigaki. H. Kawamata, R. Terao, K. Tani. S. Cyclodextrin-based artificial acyl-transferase Substrate-specific catalytic amidation of carboxylic acids in aqueous solvent. J. Am. Chem. Soc 2001, 123. 10760-10761. 

N-Acylcarboxylic acid amides s. a. Diacylamines, mixed Acyl compounds, active s. Carboxylic acid esters, active Acylcyanides... 

Vinylogs (Vinylogous) s. carboxylic acid amides, vinylogous... 

T ris(dimethylamino) phosphine I carbon tetrachloride Carboxylic acid amides from carboxylic acids s. 28, 144... 

N-substituted amides of carboxylic acids. 0-, S- and C-Nitroso compounds are also known. 

Carboxylic acid amides from carboxylic acids via carboxylic acid methyl esters s. 52, 347... 

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