Reversible formation of intermediates during H/sub 3/O/sup +/-catalyzed hydrolysis of amides. Observation of substantial /sup 18/O exchange accompanying the hydrolysis of acetanilide and N-cyclohexylacetamide
Careful mass spectrometric analysis of the /sup 18/O content of approx. 50% enriched acetanilide (2) and N-cyclohexylacetamide (3) recovered from acidic media during the course of hydrolysis reveals that both species suffer /sup 18/O loss. The percent of /sup 18/O exchange per t/sub 1/2/ of hydrolysis increases as (H/sub 3/O/sup +/) decreases. For 2 at 72/sup 0/C the amount of exchange increases from 0.5 +/- 0.5% (per t/sub 1/2/) in 1 M HCl to 9.4 +/- 0.5% in glycine buffer, (H/sub 3/O/sup +/) = 0.003 M. For 3 at 100/sup 0/C the exchange is 1.05 +/- 0.3% (per t/sub 1/2/) at 1 M HCl and 9.0 +/- 0.4% in 0.01 M HCl. When these data are used to compute k/sub ex/ (the exchange rate constant), it shows a first-order dependence on (H/sub 3/O/sup +/) followed by a plateau at high (H/sub 3/O/sup +/) for both 2 and 3.
- Research Organization:
- Univ. of Alberta, Edmonton
- OSTI ID:
- 6086040
- Journal Information:
- J. Am. Chem. Soc.; (United States), Vol. 109:15
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
AMIDES
HYDROLYSIS
HYDROCHLORIC ACID
CATALYTIC EFFECTS
CATALYSIS
OXYGEN 18
ISOTOPIC EXCHANGE
CHEMICAL REACTION KINETICS
EXPERIMENTAL DATA
MASS SPECTROSCOPY
MEDIUM TEMPERATURE
PH VALUE
CHEMICAL REACTIONS
DATA
DECOMPOSITION
EVEN-EVEN NUCLEI
HYDROGEN COMPOUNDS
INFORMATION
INORGANIC ACIDS
ISOTOPES
KINETICS
LIGHT NUCLEI
LYSIS
NUCLEI
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN ISOTOPES
REACTION KINETICS
SOLVOLYSIS
SPECTROSCOPY
STABLE ISOTOPES
400201* - Chemical & Physicochemical Properties
400202 - Isotope Effects
Isotope Exchange
& Isotope Separation