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Kinetic studies of the reactions of phthalimide with ammonia and pyrrolidine
Author(s) -
Khan M. Niyaz,
Ohayagha J. E.
Publication year - 1994
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.610070908
Subject(s) - pyrrolidine , chemistry , phthalimide , nucleophile , catalysis , intramolecular force , medicinal chemistry , ammonia , base (topology) , organic chemistry , mathematical analysis , mathematics
The kinetics of the nucleophilic cleavage of phthalimide (PTH) in buffer solutions of ammonia and pyrrolidine were determined. The reaction rates for ammonolysis of PTH revealed a buffer‐catalysed second‐order term in the rate law, but the reaction rates for pyrrolidinolysis of PTH showed buffer‐catalysed second‐ and third‐order terms in the rate law. Both ammonia and pyrrolidine revealed nucleophilic reactivity towards ionized PTH (S − ) only within the pH range of the present study. This is attributed to the occurrence of intramolecular general base–acid catalysis. General base catalysis is detected in the reactions of pyrrolidine with both non‐ionized PTH (SH) and S − . The general base‐catalysed third‐order rate constant for pyrrolidinolysis of SH is nearly 28 times larger than that of S − .