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Preparation of amides

Amides are readily prepared by acylation of ammonia and amines with acyl chlorides, anhydrides, or esters. [Pg.800]

Primary amines (RNH2) yield A-substituted amides (R CNHR). [Pg.800]

Secondary amines (R2NH) yield iV,fV-disubstituted amides (R CNR2). [Pg.801]

Examples illustrating these reactions may be found in Tables 20.2, 20.3, and 20.6. [Pg.801]

Two molar equivalents of amine are required in the reaction with acyl chlorides and acid anhydrides one molecule of amine acts as a nucleophile, the second as a Br0n-sted base. [Pg.801]

Amides are most commonly prepared by reaction of an acyl chloride or an anhydride with ammonia or an amine. Because the by-products of these reactions are acidic, base must also be added to the reaction. An excess of the amine can be employed as the base if it is inexpensive, or the reaction may be done in the presence of sodium hydroxide or some other base. Following are several examples. [Pg.824]

By using the reactions described in Sections 19.2 through 19.6, it is possible to convert one carboxylic acid derivative to any other carboxylic acid derivative. Now let s examine the reactions of these compounds with hydride and organometallic nucleophiles. In these cases the products are no longer carboxylic acid derivatives. [Pg.824]

Show all of the steps in the mechanism for this reaction and explain why the indicated product is formed and the other is not  [Pg.825]

Suggest reactions that could be used to convert this amide to the methyl ester  [Pg.825]

Any carboxylic acid derivative can be converted to any other using one or more of the reactions discussed in the previous sections. If the conversion requires going from a less reactive derivative to a more reactive one, then an indirect route may be necessary. Remember that any derivative can be hydrolyzed to a carboxylic acid using water and acid or base. Also remember that the carboxylic acid can be converted to the acyl chloride with thionyl chloride, providing access to the other derivatives. [Pg.825]

Amides can be prepared by the reaction of ammonia, primary amines or secondary amines with acid anhydrides, esters or acyl chloride. [Pg.205]

Amides with an acyl group derived from acetic acid are called acetamides. Acetamides are generally produced from the reactions of acetic anhydride with amines. [Pg.206]

SECTION 77 AMIDES FROM ACIDS AND ACID DERIVATIVES [Pg.225]

BBDl = l-/-butoxy-2-BOC-l,2-dihydroisoquinoline Saito,Y. Ouchi, H. Takahata, H. Tetrahedron 2008, 64, 11129. [Pg.226]

Mizuhara, T. Hioki, K. Yamada, M. Sasaki, H. Morisaki, D. Kunishima, M. Chem. Lett. 2008, 37, 1190. [Pg.226]

Poondra, R.R. Turner, N.J. Org. Lett. 2005, 7, 863. CO2H Boc20,NaN3,THF [Pg.227]

Conjugate reductions of unsaturated amides are listed in Section 74D (Conjugate Reduction of a,p-Unsaturated Carbonyl Compounds and Nitriles). [Pg.231]

A great deal of work has been done on the in situ activation of carboxylic acids toward nucleophilic substitution by amines. This type of reaction is fundamental for synthesis of polypeptides (see also Section 13.3.1). Dicyclohexylcarbodiimide [Pg.252]

The (V-hydroxysuccinimide that is liberated is easily removed because of its solubility in dilute base. The relative stability of the anion of A-hydroxysuccinimide is also responsible for the acyl derivative being reactive toward nucleophilic attack by an [Pg.253]

Similarly, photolabels, such as 4-azidobenzoylglycine can be attached to peptides and used to detect binding sites in proteins.137 [Pg.254]

1-Hydroxybenzotriazole is also useful in conjunction with DCCI.138 For example, Boc-protected leucine and the methyl ester of phenylalanine can be coupled in 88% yield with these reagents. [Pg.254]

Carboxylic acids can also be activated by the formation of mixed anhydrides with various phosphoric acid derivatives. Diphenyl phosphoryl azide, for example, is an effective reagent for conversion of amines to amides.140 The proposed mechanism involves formation of the acyl azide as a reactive intermediate. [Pg.254]

Another useful reagent for amide formation is compound 1. The reaction with this reagent also proceeds via a mixed carboxylic phosphoric anhydride. [Pg.153]

A recently developed method for converting esters to amides involves aluminum amides, which can be prepared from trimethylaluminum and the amine. These reagents convert esters directly to amides at room temperature. [Pg.155]

Preparations of amides and related compounds from esters have been described in Section 2C(2). [Pg.275]

Many amides have been prepared from pyrazinecarboxylic acid chlorides some are listed below with the relevant amines and references 2-chlorocarbonyl [MeNHj/ EtOAc (138) Me NH/EtOAc (138) BujNH etc/EtOAc (138) aniline/EtOAc (138, 1335) other aromatic and heterocyclic amines/EtOAc (138) sulfanilamide/ pyridine (1336) p-(2 -aminoethyl)benzenesulfonamide (1385) p-anisidine/benzene (1334) 4-hydroxypiperidine/benzene chloroform (1386) morpholine/DMF/20° (1387) 2-aminopyrimidine/benzene (1388) glycine/NaOH/ether (1201, cf. 1333, 1360)] 2-chlorocarbonyl-5-methyl [MeNHj/benzene (1337) MejNH/benzene (1337) 4-phenylpiperazine or diethanolamine/benzene-chloroform (1386) 2-chlorocarbonyl-3-phenyl (6-aminopenicillanic acid) (1024) 2-chloro-3-chloro-carbonyl (morpholine/benzene) (838) 2-chloro-5-chlorocarbonyl (NH4OH) (839) 2-chloro-6-chlorocarbonyl (Et2NH/benzene) (870, 1389) 2-chlorocarbonyl-5-hydroxy (aniline/benzene) (1055) 2-chlorocarbonyl-3-methoxy (morpholine/ benzene) (867) 2-chlorocarbonyl-5-methoxy (morpholine/benzene-chloroform) (1386) and 2-(l -chlorocarbonylethyI) (morpholine/benzene) (364). [Pg.275]

Amides have also been prepared from carboxylic acids as follows a mixture of 2-carboxypyrazine and triethylamine in methylene chloride treated with ethyl chloroformate and then morpholine gave 2-(A-morpholinocarbonyl)pyrazine (1351) 2-carboxy-5(and 6)-methylpyrazine in dioxane with tributylamine and ethyl chloroformate and then treated with ammonia gave 2-carbamoyl-5(and 6)-methylpyrazine (673), and 2-carbamoyl-5(and 6)-ethylpyrazine were prepared [Pg.275]

2- Carboxy-3-hydroxypyrazine refluxed with phosphorus tri(Af-methylanilide) in toluene gave 2-hydroxy-3-(A -methyl-A -phenyl)carbamoylpyrazine, and 2-hydroxy- [Pg.276]

3- (fV-methyl-A -p-tolyl)carbamoylpyrazine was prepared similarly (1055). 2,3-Dicarboxypyrazine heated with urea at 210° gave 2-carbamoylpyrazine (1390). [Pg.276]

No Additional Examples SECTION 77 Amides from Acid Derivatives [Pg.98]

Related Methods Amides from Amines (Section 82) [Pg.99]

SECTION 80 Amides from Alkyl, Methylenes, and Aryls [Pg.100]

Majchand-Brynaert, J.Moya-Portuguez, M., Huber, I.j Ghosez, [Pg.101]

Benneche, T. Undheim, K. Acta Chem. Scand. B., 1993, 47, 1141 [Pg.103]

Callier, A.-C. Quiclet-Sire, B. Zard. S.Z. Tetrahedron Lett., 1994, 35, 6109 [Pg.105]

Bumell-Curty, C. Roskamn. E.J. Synlett, 1993 g Q [Pg.110]

Alcaide. B. Rodn guez-Ranera, C. Rodn gucz-Vicente, A. Tetrahedron Lett., 2001, 42, 3081. [Pg.234]

Rosingana, M. Di.scordia, R.P. Soundararajan, N. Polnia,szek, R. [Pg.247]

Vauthey, I. Valot, F. Gozzi, C. Fache, F. Lemaue. M. Tetrahedron Lett., 2000, 41, 6347. [Pg.249]

Sanchez. R. Vest, G. Despres, L. Synth. Commun., 1989, 19, 2909. SECTION 78 AMIDES FROM ALCOHOLS AND THIOLS [Pg.123]

Nikifurov. A. Jirovetz. L. Buchbauer, G. Liebigs Ann. Chem., 1989, 489. SECTION 79 AMIDES FROM ALDEHYDES [Pg.124]

Melnick. M.J. Freyer, A.J. Weinreb. S.M. Tetrahedron Lett., 1988,29, 3891. PhaAs CHgCONHiBr Bf  [Pg.124]

SECTION 80 AMIDES FROM ALKYLS, METHYLENES AND ARYLS [Pg.124]

By far the most common method for preparation of amides is the reaction of ammonia or a primary or secondary amine with one of the reactive reagents described in Section 3.4.1. When acyl halides are used, some provision for neutralizing the hydrogen halide is necessary, because it will otherwise react with the reagent amine to form the corresponding salt. Acid anhydrides give rapid acylation of most amines and are convenient if available. The Schotten-Bauman conditions, which involve shaking an amine with excess anhydride or acyl chloride and an alkaline aqueous solution, provide a very satisfactory method for preparation of simple amides. [Pg.172]

CHAPTER 3 FUNCTIONAL GROUP INTERCONVERSION BY NUCLEOPHILIC SUBSTITUTION [Pg.174]

Wunsch andF. Drees, Chem. Ber. 99 110 (1966) E. Wunsch, A. Zwick, andG. Wendlberger, Chem. Ber. 100 173 (1967). [Pg.174]

A -hydroxysuccinimides can be isolated and purified, but they react rapidly with free amino groups. [Pg.175]

A great deal of work has been done on the in situ activation of carboxylic acids toward nucleophilic substitution by amines. This type of reaction forms the backbone of the methods for synthesis of peptides and proteins. (See also Section 13.6). DCC is very widely used for coupling carboxylic acids and amines to give amides. Because amines are better nucleophiles than alcohols, the leaving group in the acylation reagent need not be as reactive as is necessary for alcohols. The -nitrophenyl and 2,4,5-trichlorophenyl  [Pg.172]

CH3CH=CHCH=CHC02H -------- CH3CH=CHCH=CHCS [Pg.173]

SECTION 3.4. SYNTHETIC INTERCONVERSION OF CARBOXYLIC ACID DERIVATIVES [Pg.127]

The cyano group is at the carboxylic acid oxidation level so nitriles are potential precursors of primary amides. Partial hydrolysis is sometimes possible.A milder [Pg.129]

Give the products which would be expected to be formed under the specified reaction conditions. Be sure to specify all aspects of stereochemistry. [Pg.129]

Kawaguchi, M. Hamaoka, S. Mori. M. Tetrahedron Lett., 1993, 34, 6907 CgHi H2, ISO-C.Bamin 0 [Pg.100]

Shibata, T. Zhou, D.-Y. Onitsuka, K. Takahashi. S. Tetrahedron Lett. 2004,45,3211. [Pg.151]

Nagata, K. Kurihara, A. Miyazaki, M. Ohsawa. A. Tetrahedron Lett. 2002, 43, 3105. [Pg.154]

Bhattacharvva. S. Rana, S. Gooding, O.W. Labadie, J. Tetrahedron Lett. 2003, 44,4951. [Pg.154]

Balanarsaiah, ERaghavendra, S. Tetrahedron Lett. 2002,45,5105. [Pg.158]

Thionyl chloride is a lachrymator. Measure this material in a hood and do not inhale its vapors. Wear latex gloves when handling this chemical. [Pg.887]

Acid chlorides release hydrochloric acid upon hydrolysis, so avoid contact of such reagents with your skin. If contact occurs, immediately flood the area with water and rinse it with 5% sodium bicarbonate solution. Wear latex gloves when handling acid chlorides. [Pg.887]

Preparation Sign in at www.cengage.coin/login to read the MSDSs for the chemicals used or produced in this procedure. [Pg.888]

Amides. Use 0.5 g of the carboxylic acid to prepare the acid chloride. At the hood, pour the mixture containing the acid chloride and unchanged thionyl chloride into 15 mL of ice-cold, concentrated ammonium hydroxide solution. Be very careful when performing this addition, because the reaction is quite exothermic. Collect the precipitated amide derivative by vacuum filtration, and recrystallize the crude product from water or aqueous ethanol. [Pg.888]

Neutralize all filtrates and then flush them down the drain. [Pg.888]

BusSnH, cat. AIBN (addn over 4 h) degassed cyclohexane [Pg.105]

Ph2NH heating after 2. leads to keienes [Pg.117]

Masuda, R, Hoio. M. Ichi, T. Sasano, S. Kobayashi, T. Kuroda, C. Tetrahedron Lett., 1991, 32, 1195. [Pg.122]

Ishihashi. H. Nakamura, N. Sato, T. Takeuchi, M. Ikeda. M. Tetrahedron Lett., 1991, 32,1725. [Pg.122]

Khalafl-Nezhad. A, Mokhtari, BRad, M.N.S. Tetrahedron Lett. 2003,44,7325. [Pg.152]

Yasuda.M. Kojima, R. Tsutsui,H. Utsunomiya, D. Ishii.K. Jinnouchi.K. Shiragami.T. Yamashita.T. J. Org.Chem.2003,68,1618. [Pg.155]


Ketone formation can also be avoided if one of the functional acyl halogens ia phosgene is blocked. Carbamyl chlorides, readily obtained by the reaction of phosgene with ammonia or amines, are suitable reagents for the preparation of amides ia direct Friedel-Crafts acylation of aromatics. The resulting amides can be hydroly2ed to the corresponding acids (134) ... [Pg.560]

The hydrogenolysis of hydroxamic acids (22) and hydra2ides (23) has also been used to synthesi2e amides. One of the earliest methods for the preparation of amides consists of treating acid chlorides with dry ammonia or an amine (24). [Pg.183]

N-Methyllauramide, N-methyhnyristamide, and N-methyl-pelargonamide can be prepared in 95-98% yield by adaptation of the method used by Roe, Scanlan, and Swern for the preparation of amides of oleic and 9,10-dihydroxystearic acids. [Pg.49]

This is a very general and mild method for the preparation of amides, applicable to large structural variations in both the acid and the amine. A variety of chloro-formates can be employed, but isobutyl chloroformate is used most often. The solvent is not critical, but generally, THE is used. [Pg.443]

Although, the enzymatic reaction of esters with amines or ammonia have been well documented, the corresponding aminolysis with carboxylic acids are rarer, because of the tendency of the reactants to form unreactive salts. For this reason some different strategies have been used to avoid this problem. Normally, this reaction has been used for the preparation of amides of industrial interest, for instance, one of the most important amides used in the polymer industry like oleamide has been produced by enzymatic amidation of oleic acid with ammonia and CALB in different organic solvents [10]. [Pg.174]

The treatment of acyl halides with ammonia or amines is a very general reaction for the preparation of amides.The reaction is highly exothermic and must be carefully controlled, usually by cooling or dilution. Ammonia gives unsubstituted amides, primary amines give A-substituted amides, and secondary amines give N,N-disubstituted amides. Arylamines can be similarly acylated. In some cases aqueous... [Pg.506]

The mixed carbonic anhydride procedure8-7 has been useful in the preparation of amide linkages and thiol esters. Mixed carbonic anhydrides have successfully acylated, under very mild conditions, the carb-anions derived from diethyl ethylmalonate and diethylcadmium.8 The latter gives as a product the corresponding ketone. Mixed anhydrides derived from acetic and acetylsalicylic acids give results similar to those described here.8... [Pg.12]

The total syntheses of these pepper alkaloids are not those of pyrrolidines but rather syntheses of their acid parts. Thus dihydrowisanidine (137) has been prepared by a series of reactions, the key step of which is the formation of the carbon-carbon double bond by a Wittig-Homer reaction (217, 218). Schemes 41 and 42 summarize two syntheses of okolasine from sesamolmethyl ether (279) of course, routes to okolasine also yield the corresponding piperidine alkaloid wisanine. Molybdenum-catalyzed elimination of allylic acetate (149) yielded (E,E)-diene ester 150 en route to trichonine (220) worthy of note is the use of an aluminum amide in the preparation of amide 143 from ester 150 (Scheme 43). [Pg.326]

The reagent is prepared1 by reaction of phosgene with 3,5-dioxo-4-methyl-l,2,4-oxadiazolidine in refluxing toluene (82% yield). It serves as a coupling reagent for esterification and preparation of amides and carbamates. [Pg.73]

The use of acid chlorides in the preparation of amides has been reviewed.7 The diethylamine was distilled from calcium hydride prior to use. [Pg.84]

Ritter reaction org chem A procedure for the preparation of amides by reacting alkenes or tertiary alcohols with nitriles in an acidic medium. rid-ar re,ak-sh3n ) Ritz s combination principie spect The empirical rule that sums and differences of the frequencies of spectral lines often equal other observed frequencies. Also known as combination principle. rit-soz, kam-b3 na-sh3n. prin-sa-pal )... [Pg.328]

Benzotriazoles are neutral acylating agents, successfully used for the preparation of amides, oxamides and hydrazides The acylbenzotriazoles 95a-d are prepared from carboxylic acids 94a-d by reaction with l-methanesulfonyl-l//-benzotriazole (Scheme 51). Reaction of 1-benzoyl-l//-benzotriazole with hydroxylamine hydrochloride in the... [Pg.189]

The preparation of amides directly from alkyl esters is also feasible but is usually too slow for preparative convenience. Entries 4 and 5 in Scheme 3.6 are successftd examples. The reactivity of ethyl cyanoacetate (entry 4) is higher than that of unsubstituted aliphatic esters because of the inductive effect of the cyano group. [Pg.177]

Fig. 12 Synthesis route for preparation of amide surfactants. MsCl, EtsN, THF and DCM stand for mesyl chloride, triethylamine, tetrahydrofuran and dichloromethane, respectively... Fig. 12 Synthesis route for preparation of amide surfactants. MsCl, EtsN, THF and DCM stand for mesyl chloride, triethylamine, tetrahydrofuran and dichloromethane, respectively...
Preparation of amides Ammonia, 1° and 2° amines react with carboxylic acids to produce, respectively, 1°, 2° and 3° amides, through a nucleophilic acyl substitution reaction. The reaction of ammonia and a carhoxylic acid initially forms a carhoxylate anion and an ammonium cation. Normally the... [Pg.250]

Preparation of amides Ammonia and 1° and 2° amines react with acid chlorides and acid anhydrides to give 1°, 2° and 3° amides, respectively, in the presence of excess pyridine (C5H5N) or triethylamine (Et3N). In the case of acid anhydride, two molar equivalents of ammonia or amines are required. [Pg.252]

The treatment of acyl halides with ammonia or amines is a very general reaction for the preparation of amides.843 The reaction is highly exothermic and must be carefully controlled,... [Pg.417]

Support-bound phenols, oximes, and related compounds yield, upon acylation, esters that are highly susceptible to nucleophilic cleavage. These esters are often used as insoluble acylating agents for the preparation of amides or esters, but only occasionally as linkers for carboxylic acids [113]. These linkers are considered in Sections 3.3.3 and 3.5.1. [Pg.50]


See other pages where Preparation of amides is mentioned: [Pg.859]    [Pg.859]    [Pg.859]    [Pg.859]    [Pg.814]    [Pg.176]    [Pg.176]    [Pg.100]    [Pg.528]    [Pg.252]    [Pg.252]    [Pg.256]    [Pg.181]    [Pg.178]    [Pg.289]    [Pg.319]    [Pg.355]    [Pg.145]    [Pg.245]    [Pg.245]    [Pg.245]    [Pg.307]    [Pg.146]    [Pg.150]    [Pg.172]    [Pg.269]    [Pg.100]    [Pg.175]   
See also in sourсe #XX -- [ Pg.1006 ]




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Amides, preparation

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