Benzamide, hydrolysis reactions

Reaction 12, the acid-catalyzed hydrolysis of substituted benzamides, has p = — 0.22, so the reaction is modestly facilitated by electron-donating groups. This suggests that protonation of the amide is kinetically important ... 

Acid anhydride-diol reaction, 65 Acid anhydride-epoxy reaction, 85 Acid binders, 155, 157 Acid catalysis, of PET, 548-549 Acid-catalyzed hydrolysis of nylon-6, 567-568 of nylon-6,6, 568 Acid chloride, poly(p-benzamide) synthesis from, 188-189 Acid chloride-alcohol reaction, 75-77 Acid chloride-alkali metal diphenol salt interfacial reactions, 77 Acid chloride polymerization, of polyamides, 155-157 Acid chloride-terminated polyesters, reaction with hydroxy-terminated polyethers, 89 Acid-etch tests, 245 Acid number, 94 Acidolysis, 74 of nylon-6,6, 568... 

These reactions involve a diazonium ion (see 12-47) and are much faster than ordinary hydrolysis for benzamide the nitrous acid reaction took place 2.5 x lo times faster than ordinary hydrolysis. Another procedure for difficult cases involves treatment with aqueous sodium peroxide. In still another method, the amide is treated with water and f-BuOK at room temperature. " The strong base removes the proton from 107, thus preventing the reaction marked k j. A kinetic study has been done on the alkaline hydrolyses of A-trifluoroacetyl aniline derivatives. Amide hydrolysis can also be catalyzed by nucleophiles (see p. 427). 

Now that steric parameters have been introduced in this way, the treatment can be extended to include the reactions of o-substituted benzene derivatives as well. Thus for the acid-catalysed hydrolysis of o-substituted benzamides (43), the value of 8 is found to be 0-81 so this reaction is apparently slightly less susceptible to the steric... 

Capon et al., 1978. No reference bimolecular reaction is available, but o-cyanobenzoic acid is hydrolysed over 10 times faster than phthalamic acid (A.3.9), although benzonitrile is less reactive than benzamide towards acid hydrolysis. [Rate constants for hydrolysis are (1-2) x 10 s for benzonitrile in 1 M acid (Hyland and O Connor, 1973) and 3.5 x 10-4 dm3 mol-1 s 1 for benzamide (Bender et al., 1958), both measured at 100°]... 

Benzamides 565 without any substituent at the para position reacted with lithium and a catalytic amount of naphthalene under Barbier-type reaction conditions (in the presence of a carbonyl compound) in THF at —78 °C to give, after hydrolysis, the corresponding dearomatized products 566 (Scheme 151). When 567 was used as starting material with a 4-ferf-butyl group in p-position, and using 3-pentanone as electrophile and under the same reaction conditions, the fraw -product 568 was the only one isolated . 

The methoxyketene 297, coordinated to Cr carbonyl, is formed from methoxy-carbene easily by insertion of CO under irradiation [90]. An ester is formed by the reaction of ketene with alcohol. The aminocarbene complex 298 was prepared from benzamide and converted to phenylalanine ester 300 under irradiation of sunlight in alcohol via ketene 299 [91]. The eight-membered lactone 304 was prepared in high yield by the reaction of the alkyne 301 having the OH group in a tether with Cr carbene without irradiation. The vinylcarbene 302 is formed at first and converted to the vinylketene intermediate 303 as expected. The keto lactone 304 is formed from 303 by intramolecular reaction with the OH group and hydrolysis [92],... 

The analogues [menthyloxy(tosyloxy)iodo]benzenes, with both (+) and (-) forms of menthol, in their reactions with non-symmetric sulphides caused considerable asymmetric induction hydrolysis of their salts afforded sulphoxides of high optical purity [52]. By using A-phenyliodonio tosylates of benzamide (and some other similar derivatives from different amides, Section 7.4.1) dimethyl sulphide was converted into amidosulphonium tosylates which can serve as the precursors of sulphilimines [51] ... 

After converting A -Phth-protected amines into the corresponding 2-(pyrrolidinocarbon-yl)benzamide derivative, Dieckmann reactions, ester hydrolysis, and transesterfication can be carried out. This strategy of pyrrolidine-based deactivation of phthaloyl-protected anoines followed by reclosure of the phthaloyl group has successfully been applied in the synthesis of (3-lactam antibiotics.P l... 

A vast amount of research has shown that the Hammett relationship holds for hundreds of sets of reactions. (Ionization of 40-odd p-substituted benzoic acids, for example, is one set.) By use of just two tables—one of a constants and one of p constants— we can calculate the relative Keq s or relative rates for thousands of individual reactions. For example, from the a value for W-NO2 ( + 0.710) and the p value for ionization of benzoic acids in water at 25" (+1.000), we can calculate that Ka for m-nitrobenzoic acid is 5.13 times as big as the Ka for benzoic acid. Using the same acid-catalyzed hydrolysis of benzamides in 60% ethanol at 80° (-0.298), we can calculate that m-nitrobenzamide will be hydrolyzed only 0.615 as fast as benzamide. 

The dramatic increases in reaction rates that occur in enzyme-catalyzed reactions can be seen for representative systems in the data given in Table 2.2.4 The hydrolysis of the representative amide benzamide by acid or base yields second-order rate constants that are over six orders of magnitude lower than that measured for ben-zoyl-L-tyrosinamide in the presence of the enzyme a-chymotrypsin. An even more dramatic rate enhancement is observed for the hydrolysis of urea The acid-catalyzed hydrolysis is nearly 13 orders of magnitude slower than hydrolysis with the enzyme urease. The disprotionation of hydrogen peroxide into water and molecular oxygen is enhanced by a factor of 1 million in the presence of catalase. 

Roberts and Whiting developed a method for effecting the anhydrous hydrolysis of esters and nitriles in DMSO. A solution of sodium methylsulfinylmethide is prepared from sodium hydride and DMSO and titrated with a solution of an appropriate amount of water in DMSO, using triphenylmethane as indicator. This produces a fine suspension of sodium hydroxide which hydrolyzes ethyl benzoate very rapidly at room temperature. As compared with reactions in hydroxylic solvents, rates are enhanced by a factor of 10 -10 . Benzonitrile is hydrolyzed to benzamide. Methyl and ethyl mesitoates are hydrolyzed readily at 25°. 

The formation of the tetracovalent intermediate appears to be the rate-determining step. On the other hand the hydroxide ion-catalysed hydrolysis of benzamide (Bender and Ginger, 1955) is accompanied by oxygen exchange with solvent (see Table 6). In basic solution, the reaction proceeds via the symmetrical intermediate. 

---