Determination of the acid dissociation constants of barbiturates by an accurate method of pH measurement. II. Correlations between normal and N-methylated barbiturates | Health & Environmental Research Online (HERO)

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Citation
Tags

HERO ID

1621433

Reference Type

Journal Article

Title

Determination of the acid dissociation constants of barbiturates by an accurate method of pH measurement. II. Correlations between normal and N-methylated barbiturates

Author(s)

Doornbos, DA; De Zeeuw, RA

Year

1971

Is Peer Reviewed?

Journal

Pharmaceutisch Weekblad
ISSN: 0031-6911

Report Number

IPA/73/069337

Volume

Weekbl

Issue

REF 5

Page Numbers

134-141

Abstract

IPA COPYRIGHT: ASHP The potentiometric determination of the ""proton lost'' dissociation constant of six N-methylated barbiturates was carried out. The constants are tabulated as association constants KH1 for an ionic strength mu=0.10 and t=20.0DGC. The influence of substituents at N1 and C5 on the acid strength is discussed. From the determination of the ""proton gained'' dissociation constants in strongly acid medium it could not be concluded how many protons can be bound. The 6 barbiturates studied were: 1-methyl-5,5-dipropyl-; 1,5-dimethyl-5-isopropyl-; 1,5-dimethyl-5-ethyl-; 1-methyl-5-ethyl-5-butyl-; 1-methyl-5,5-diallyl-; and 1-methyl-5-propyl-5-isopropylbarbituric acid.

Keywords

Barbiturates; dissociation constants; N-methylated compounds; Potentiometry; N-methylated; N-methylated