Preparation and Reactions of Amides

There has been a great deal of work recently on the preparation and reaction of amides. Susumu Saito ofNagoya University prepared J. Am. Chem. Soc. 2009,131,8748) adiaryl boronic acid that catalyzed the methanolysis of an imide 13 to the methyl ester 14 and the oxazolidinone 15. Jaume Vilarrasa of the Universitat de Barcelona reported J. Org. Chem. 2009, 74, 2203) the catalyzed condensation of an acid 16 with an azide 17 to give... 

This chapter concerns the preparation and reactions of acyl chlorides acid anhydrides thioesters esters amides and nitriles These com pounds are generally classified as carboxylic acid derivatives and their nomenclature is based on that of carboxylic acids... 

A/-Vinylamides and /V-vinylimides can be prepared by reaction of amides and imides with acetjiene (3), by dehydration of hydroxyethyl derivatives (4), by pyrolysis of ethyUdenebisamides (5), or by vinyl exchange (6), among other methods the monomers are stable when properly stored. 

Hammerschmidt, F. Hanninger, A. Enantioselective deproto nation of benzyl phosphates by homochiral lithium amide bases. Configurational stability of benzyl carbanions with a dialkoxyphosphoryloxy substituent and their rearrangement to optically active a-hydroxy phosphonates. Chem. Ber. 1995, 328, 823-830. Avolio, S. Malan, C. Marek, I. Knochel, P. Preparation and reactions of functionalized magnesium carbenoids. Synlett 1999, 1820-1822. 

This review is principally concerned with the preparation and reactions of the furan primary amines 1 and 2. Where appropriate we have included related secondary and tertiary amines, and also amides and similar N-substituted amines but no attempt has been made to provide comprehensive coverage of non-primary amines or polycyclic derivatives. 

Dipeptide formation, by condensation of one amino add with the NCA of a second, is a fadle process, but there are difficulties in controlling the amide bondforming reaction when the NCA technology is applied to heteropolymers. An additional problem is the fact that NCAs themselves are only accessible by less-than-straightforward routes. These often involve harsh reaction conditions, long reaction times with poor yields, and, not inconsequentially, the use of toxic reagents [821]. Comprehensive reviews on the preparation and reactions of NCAs have appeared in the literature [822, 823]. 

Polymerization of castor od, chemical or oxidative, results in higher viscosity or bodied ods that are more usehd in urethane coatings than the untreated castor od (87). Other castor derivatives used to prepare urethanes are amides prepared by reaction of castor od and alkanolamines, amides of ricinoleic acid with long-chain di- and triamines, and butanediol diricinoleate (88,89). 

The in-out bicyclic amines prepared by Simmons and Park bear a remarkable semblance to the cryptands but lack the binding sites in the bridges. As a result, these molecules interact with electrophiles in a fashion similar to other tertiary amines and generally do not exhibit strong interactions with alkali or alkaline earth metal ions. The in-out bicyclic amines are prepared by reaction of the appropriate acid chlorides and amines in two stages to yield the macrobicyclic amine after reduction of the amidic linkages. A typical amine is shown above as compound 18. 

Tetrahydroharman, m.p. 179-80°, has been prepared by a number of workers by a modification of this reaction, viz., by the interaction of tryptamine (3-)5-aminoethylindole) with acetaldehyde or paraldehyde and Hahn et al. have obtained a series of derivatives of tetrahydronorharman by the use of other aldehydes and a-ketonic acids under biological conditions of pH and temperature, while Asahina and Osada, by the action of aromatic acid chlorides on the same amine, have prepared a series of amides from which the corresponding substituted dihydronorharmans have been made by effecting ring closure with phosphorus pentoxide in xylene solution. 

Nickel peroxide is a solid, insoluble oxidant prepared by reaction of nickel (II) salts with hypochlorite or ozone in aqueous alkaline solution. This reagent when used in nonpolar medium is similar to, but more reactive than, activated manganese dioxide in selectively oxidizing allylic or acetylenic alcohols. It also reacts rapidly with amines, phenols, hydrazones and sulfides so that selective oxidation of allylic alcohols in the presence of these functionalities may not be possible. In basic media the oxidizing power of nickel peroxide is increased and saturated primary alcohols can be oxidized directly to carboxylic acids. In the presence of ammonia at —20°, primary allylic alcohols give amides while at elevated temperatures nitriles are formed. At elevated temperatures efficient cleavage of a-glycols, a-ketols... 

Amides are usually prepared by reaction of an acid chloride with an amine (Section 21.4). Ammonia monosubstituted amineS and disubstituted amines all undergo the reaction. 

Zinc borohydride, which is also a useful reagent,66 is prepared by reaction of ZnCl2 with NaBH4 in THF. Owing to the stronger Lewis acid character of Zn2+, Zn(BH4)2 is more reactive than NaBH4 toward esters and amides and reduces them to alcohols and amines, respectively.67 Zn(BH4)2 reduces carboxylic acids to primary alcohols.68 The reagent also smoothly reduces a-aminoacids to (3-aminoalcohols.69... 

In a detailed investigation, Turner and coworkers have described the preparation and application of solid-supported cyclohexane-1,3-dione as a so-called capture and release reagent for amide synthesis, as well as its use as a novel scavenger resin [125]. Their report included a three-step synthesis of polymer-bound cyclohexane-1,3-dione (CHD resin, Scheme 7.104) from inexpensive and readily available starting materials. The key step in this reaction was microwave-assisted complete hydrolysis of 3-methoxy-cyclohexen-l-one resin to the desired CHD resin. 

Aldonamides are readily prepared by reaction of lactones with liquid ammonia (86,99,100), with ammonium hydroxide (101,102), or by bubbling ammonia gas into alcoholic solutions of the sugar lactones (103-104). Aldonamides of the tetronic adds are stable in aqueous solution (105), but penton- or hexon-amides are hydrolyzed, as shown by the change of the optical rotation of the amide solutions (106). The hydrolysis is catalyzed by acids and bases, and the product was the ammonium salt of the aldonic acid. 

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