Solvolysis of pyridoxal hydrochloride in alcohols

Yoshiko Itoh, R. Yoda, Y. Matsushima

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

HPLC, 1H-NMR, MS and product analysis showed that pyridoxal hydrochloride was solvolyzed in methanol to form pyridoxal monomethylacetal. The reaction followed first order kinetics with the rate constant of 1.45 x 10-4 s-1 at 40 °C. The rate was not appreciably enhanced in the presence of an excess amount of HCl. The reaction was greatly retarded by addition of an equimolar amount of KOH. The results showed that the pyridinium-phenol species of pyridoxal hemiacetal is reactive. The reaction is responsible for the 'aging' of alcoholic solutions of pyridoxal, which has caused poor reproducibility of the kinetic data for the formation of Schiff bases with amino acids.

Original languageEnglish
Pages (from-to)1019-1022
Number of pages4
JournalChemical and Pharmaceutical Bulletin
Volume41
Issue number6
Publication statusPublished - 1993

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Pyridoxal
Alcohols
Kinetics
Schiff Bases
Phenol
Methanol
Rate constants
Aging of materials
High Pressure Liquid Chromatography
Nuclear magnetic resonance
Amino Acids

ASJC Scopus subject areas

  • Chemistry(all)
  • Organic Chemistry
  • Drug Discovery
  • Pharmacology

Cite this

Solvolysis of pyridoxal hydrochloride in alcohols. / Itoh, Yoshiko; Yoda, R.; Matsushima, Y.

In: Chemical and Pharmaceutical Bulletin, Vol. 41, No. 6, 1993, p. 1019-1022.

Research output: Contribution to journalArticle

Itoh, Y, Yoda, R & Matsushima, Y 1993, 'Solvolysis of pyridoxal hydrochloride in alcohols', Chemical and Pharmaceutical Bulletin, vol. 41, no. 6, pp. 1019-1022.
Itoh, Yoshiko ; Yoda, R. ; Matsushima, Y. / Solvolysis of pyridoxal hydrochloride in alcohols. In: Chemical and Pharmaceutical Bulletin. 1993 ; Vol. 41, No. 6. pp. 1019-1022.
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N2 - HPLC, 1H-NMR, MS and product analysis showed that pyridoxal hydrochloride was solvolyzed in methanol to form pyridoxal monomethylacetal. The reaction followed first order kinetics with the rate constant of 1.45 x 10-4 s-1 at 40 °C. The rate was not appreciably enhanced in the presence of an excess amount of HCl. The reaction was greatly retarded by addition of an equimolar amount of KOH. The results showed that the pyridinium-phenol species of pyridoxal hemiacetal is reactive. The reaction is responsible for the 'aging' of alcoholic solutions of pyridoxal, which has caused poor reproducibility of the kinetic data for the formation of Schiff bases with amino acids.

AB - HPLC, 1H-NMR, MS and product analysis showed that pyridoxal hydrochloride was solvolyzed in methanol to form pyridoxal monomethylacetal. The reaction followed first order kinetics with the rate constant of 1.45 x 10-4 s-1 at 40 °C. The rate was not appreciably enhanced in the presence of an excess amount of HCl. The reaction was greatly retarded by addition of an equimolar amount of KOH. The results showed that the pyridinium-phenol species of pyridoxal hemiacetal is reactive. The reaction is responsible for the 'aging' of alcoholic solutions of pyridoxal, which has caused poor reproducibility of the kinetic data for the formation of Schiff bases with amino acids.

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