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Reactivity of a tetrahedral intermediate in hydrolysis of N ‐acetylpyrrole
Author(s) -
Cipiciani Antonio,
Savelli Gianfranco,
Bunton Clifford A.
Publication year - 1984
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570210409
Subject(s) - chemistry , tetrahedral carbonyl addition compound , deprotonation , reactivity (psychology) , equilibrium constant , aqueous solution , hydrolysis , medicinal chemistry , reaction rate constant , hydrolysis constant , base (topology) , computational chemistry , organic chemistry , kinetics , catalysis , nucleophile , medicine , ion , mathematical analysis , physics , alternative medicine , mathematics , pathology , quantum mechanics
Base hydrolysis of N ‐acetylpyrrole ( 1a ) involves formation of an anionic tetrahedral intermediate ( 2a ). The equilibrium constant between these two species can be estimated by extrapolation based on the equilibrium constants for hydration of N ‐trichloroacetyl‐ and N ‐trifluoroacetylpyrrole and the estimated p K a for deprotonation of the hydrates of these compounds. Inductive effects upon hydration and deprotonation of the hydrates were estimated by analogy with inductive effects upon the equilibrium reactions of chloral and acetaldehyde. The free energies of activation for formation and return of 2a are approximately 16 and 12.5 Kcal mole −1 respectively and for conversion of 2a to products 11 Kcal mole −1 in aqueous 1 M OH − .