Acetamide, hydrolysis

A certain amount of hydrolysis of the original acetamide to acid and ammonia always occurs, and the final amine always contains traces of ammonia. This is separated by extracting the mixed anhydrous hydrochlorides with absolute ethanol, which dissolves the amine hydrochloride but not the ammonium chloride filtration of the hot ethanolic extract removes the ammonium chloride, whilst the amine hydrochloride crystallises readily from the filtrate on cooling. 

An excess of acetic acid is usually added before heating in order to repress the hydrolysis (and also the thermal dissociation) of the ammonium acetate, thus preventing the escape of ammonia. The excess of acetic acid, together with the water, is removed by slow fractional distillation. The method is rarely used except for the preparation of acetamide. 

By the action of concentrate aqueous ammonia solution upon esters. This process is spoken of as ammonolysls of the ester, by analogy with hydrolysis applied to a similar reaction with water. If the amide is soluble in water, e.g., acetamide, it may be isolated by distillation, for example ... 

Water hydroly2es pure diketene only slowly to give acetoacetic acid [541-50-4] which quickly decomposes to acetone and carbon dioxide, but increasing the pH or adding catalysts (amines, palladium compounds) increases the rate of hydrolysis. The solvolysis of diketene in ammonia results in aceto acetamide [5977-14-0] if used in stoichiometric amounts (99), and P-arninocrotonarnide [15846-25-0] if used in excess (100). 

Adamantylamine is prepared from the corresponding alcohol or bromide by bridgehead cation generation in the presence of acetonitrile (49). Selective hydrolysis of the resultant acetamide to the rigid cycloahphatic amine by acid or base is difficult. 

Isomer separation beyond physical fractional crystallization has been accompHshed by derivatization using methyl formate to make /V-formyl derivatives and acetic anhydride to prepare the corresponding acetamides (1). Alkaline hydrolysis regenerates the analytically pure amine configurational isomers. 

Solubility. Poly(vinyl alcohol) is only soluble in highly polar solvents, such as water, dimethyl sulfoxide, acetamide, glycols, and dimethylformamide. The solubiUty in water is a function of degree of polymerization (DP) and hydrolysis (Fig. 4). Fully hydrolyzed poly(vinyl alcohol) is only completely soluble in hot to boiling water. However, once in solution, it remains soluble even at room temperature. Partially hydrolyzed grades are soluble at room temperature, although grades with a hydrolysis of 70—80% are only soluble at water temperatures of 10—40°C. Above 40°C, the solution first becomes cloudy (cloud point), followed by precipitation of poly(vinyl alcohol). 

The chloroacetamide can also be cleaved by first converting it to the pyridinium-acetamide (Pyr, 90°, 1 h, 70-90% yield) followed by mild basic hydrolysis (0.1 7/NaOH, 25°). ... 

If ki = ki, p7/min = U2 pA" . This is an unusual condition it has been observed in the hydrolysis of acetamide at 100°C. Since pA" = 12.32 at 100°C, the minimum rate in this reaction occurs at pH 6.16. For ester hydrolyses, ki is usually greater than ki, and the minimum is observed near pH 5-6 (at room temperature). Equation (6-57) is used in the construction of a calculated pH-rate profile, when it allows... 

This boronate was developed to confer added stability toward hydrolysis. It was shown to be substantially more stable to hydrolysis than the simple phenyl boronate because of coordination of the the ortho acetamide to the boronate. ... 

In a diacetamide, one acetamide is easily cleaved by hydrolysis with NaOMe and MeOH, which is consistent with the use of A,A-diacetyl-aminoquinazoUne, 2-trifluoromethyl-A, A-diacetylanihne, and A-methoxydi-acetamide as amidating agents. ... 

Figure 6.14 Enzymatic side chain cleavage of penicillins. 6-Aminopenicillanic acid, a valuable intermediate for the production of various semi-synthetic penicillins, can be obtained through enzyme-mediated hydrolysis of the phenylacety group of penicillin G or the phenoxyacetyl group of penicillin V. The active site of the enzyme recognises the aromatic side chain and the amide linkage, rather than the penidllin nucleus. Chemical entitles other than penicillins are therefore often good substrates, as long as they contain the aromatic acetamide moiety.

Aminotrimethanephosphonic acid is formed from formamide, acetamide, urea, or alkanenitriles with phosphorous acid [296]. By reaction of monoalkyl phosphite or P406 with glacial acetic acid or the corresponding anhydride ethane-1 -hydroxy-1,1-diphosphonic acid is formed after hydrolysis [297,298]. P406 can be obtained from P4 and 02 in a high yield of 85-90% [299]. 

The tendency for N-nitrosamides to undergo hydrolysis by a nucleophilic catalysed pathway has been confirmed by studies of N-alkylnitroso acetamides (22) Results summarised in Table I for N -n-butyl-JJ -nitroso acetamide show that its decomposition is also subject to steric constraints (2,6-lutidinestrong nucleophiles (eg. imidazole, thiols) irrespective of their base strength (pK ). Further, the second order dependence on [Imidazole] is more clearly defined for the decomposit-... 

Whereas under the conditions specified above JV-acetylpyrrole, like a typical acetamide, is not detectably hydrolyzed in neutral aqueous medium, the half-life of N-acetylpyrazole is 908 min, and that of A-acetylimidazole is reduced to 41 min for 1-acetyl-1,2,4-triazole and for the isomeric 1-acetyl-1,2,3-triazole, half-lives of 6.4 and 26.6 min, respectively, were observed (for an explanation of the different reactivities of the two pairs of isomers see above). Hydrolysis of TV-acetyltetrazole under the same conditions occurs too rapidly to be measured with conventional spectroscopic techniques. The reaction enthalpy AH was determined for A-acetylimidazole to be — 4.83 kcal/mol for the corresponding 1,2,4-triazolide the value was — 7.29, and for the tetra-zolide — 10.31 kcal/mol. 111... 

Kostic el al. discovered that Pd11 complexes, when attached to tryptophan residues, can rapidly cleave peptides in acetone solutions to which a stoichiometric amount of water is added, for hydrolysis.436 The indole tautomer in which a hydrogen has moved from the nitrogen to C(3) is named indolenine. Its palladium(II) complexes that are coordinated via the nitrogen atom have been characterized by X-ray crystallography and spectroscopic methods.451 Binuclear dimeric complexes between palladium(II) and indole-3-acetate involve cyclopalladation.452 Bidentate coordination to palladium(II) through the N(l) and the C(2) atoms occurs in binuclear complexes.453 Reactions of palladium(II) complexes with indole-3-acetamide and its derivatives produced new complexes of unusual structure. Various NMR, UV, IR, and mass spectral analyses have revealed bidentate coordination via the indole carbon C(3) and the amide oxygen.437... 

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