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Can. J. Chem. 55,640 (1977).The hydrolysis of the amide linkage of 2'-phosphonobenzanilide, 1, occurs with nucleophilic assistance from the adjacent phosphonic acid moiety. The basic component of buffers in acidic solutions provides additional rate acceleration. A Bransted plot yields a straight line for buffers of phosphoric acid, cyanoacetic acid, chloroacetic acid, and dichloroacetic acid with P 2 1.0.It is suggested that the second acidic group of the phosphonic acid of 1 dissociates upon formation of an addition intermediate, leading to a zwitterion (TI). This zwitterionic intermediate decomposes in the rate-determining step, with added base or water removing a proton from a hydroxyl group of the intermediate. The product is a mixed phosphonic-carboxylic anhydride which hydrolyzes rapidly. It is concluded that a phosphoric acid derivative is a particularly good catalyst for this type of reaction since a stabilized intermediate can be internally generated along the reaction coordinate.RONALD KLUGER et C.-H. LAM. Can. J. Chem. 55, 640 (1977).L'hydrolyse du lien amide du phosphono-2' benzanilide 1 se produit avec I'aide de l'acide phosphonique adjacent agissant comme nucli.ophile. Le composant basique des tampons, en solutions acides, fournit une autre accileration de vitesse. Une courbe de Bronsted conduit a une ligne droite pour des tampons d'acide phosphorique, d'acide cyanoacetique, d'acide chloroacktique et d'acide dichloroacCtique avec une valeur de = 1.0. On suggkre que le second groupe acide de l'acide phosphonique de 1 se dissocie lors de la formation d'un intermediaire d'addition qui conduit a un zwitterion (T'). Ce zwitterion intermediaire se decompose dans ]'&tape determinant la vitesse de la rCaction alors que les bases ajoutees ou l'eau enlevent un proton du groupe hydroxyle de I'intermediaire. Le produit est un anhydride mixte phosphonique-carboxylique qui s'hydrolyse rapidenient. On en conclut qu'un derive d'acide phosphorique est un catalyseur qui est particulikrement bon pour ce type de reaction puisqu'un intermediaire stabilise peut ktre gCnCre d'une faqon interne au cours de la reaction.[Traduit par le journal]Covalent interactions of amides and phosphates are of particular interest because of their potential significance in aggregates of proteins and nucleotides. We have been studying these interactions in model compounds containing the two functionalities in reactive proximity using hydrolysis rates as a probe (1-3). Evidence that a phosphate derivative can undergo addition to an amide includes our observation that a neighboring phosphonic acid markedly accelerates the hydrolysis of an amide (2). We have examined the mechanism of this catalytic interaction in detail in order to obtain an understanding of the stepwise processes involved. Although analogies can be drawn to situations in which carboxylic acids participate in the hydrolysis of amides, contrasts provide important information about the details of both types of interactions. In this report, we present evidence that external Bran...

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