Hydrolyses of 2- and 4-fluoro N-heterocycles. 3. Nucleophilic catalysis by buffer bases in the general acid catalyzed hydrolysis of 4-fluoroquinaldine

Journal Article · Fri Jan 06 04:00:00 EST 1989 · J. Org. Chem.; (United States)

DOI:https://doi.org/10.1021/jo00262a037· OSTI ID:6085172

Muscio, Jr, O J; Theobald, P G; Rutherford, D R

Pseudo-first-order rate constants and catalytic rate constants are reported for the buffer-catalyzed hydrolysis of 4-fluoroquinaldine (1) in carboxylic acid and phosphoric acid buffers. The buffer catalysis is consistent with specific acid, general base catalysis. Hydrolyses in 99% /sup 18/O-labeled acetate, indicate that the predominant catalytic mode for the acetic acid/acetate buffer system is nucleophilic catalysis by the acetate anion coupled with specific acid catalysis. The other buffers presumably react in a similar manner. A Broensted-type plot of the catalytic rate constants for hydrolysis of protonated 1 has a slope of 0.57, with formate deviating positively from the line determined by acetate, chloroacetate, monohydrogen phosphate, and water. This Broensted slope is less than that found for hydrolysis of the 2-fluoro-1-methylpyridinium ion, 2, but is still within the range expected for aromatic nucleophilic substitution. Rate constants and /sup 18/O-labeling results for hydrolysis in acetate buffer are also reported for 4-acetoxyquinaldine (3), the proposed intermediate in the acetate-catalyzed hydrolysis of 1. 15 references, 5 figures, 3 tables.

• Research Organization: Murray State Univ., KY (USA)
• OSTI ID: 6085172
• Journal Information: J. Org. Chem.; (United States), Journal Name: J. Org. Chem.; (United States) Vol. 54:1; ISSN JOCEA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
400202 -- Isotope Effects
Isotope Exchange
& Isotope Separation
ACETATES
AROMATICS
AZAARENES
AZINES
CARBOXYLIC ACID SALTS
CHEMICAL REACTIONS
DATA
DECOMPOSITION
EVEN-EVEN NUCLEI
EXPERIMENTAL DATA
HETEROCYCLIC COMPOUNDS
HYDROGEN COMPOUNDS
HYDROLYSIS
INFORMATION
ISOTOPES
LABELLED COMPOUNDS
LIGHT NUCLEI
LYSIS
NUCLEI
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN 18
OXYGEN COMPOUNDS
OXYGEN ISOTOPES
PYRIDINES
QUINALDINE
QUINOLINES
SOLVOLYSIS
STABLE ISOTOPES
WATER