Issue 11, 1993

Simultaneous C- and N-nitrosation of synephrine. A kinetic study

Abstract

A kinetic study of the initial step of the nitrosation of synephrine, N-acetylsynephrine and ephedrine by sodium nitrite has been carried out in acid medium at 310 K and ionic strength 0.36 mol dm–1. In order to simplify the reaction, [nitrite] > [amine] has been used. The absorbance changes at 300 nm (synephrine and N-acetylsynephrine) and at 332/323 nm (ephedrine) were measured and then analysed according to the initial rate procedure. The results are interpreted on the basis of a simultaneous nitrosation of the amine and phenolic groups in synephrine. Unlike the early reports the global constants for N-nitrosation (0.142 dm6 mol–2 s–1) and C-nitrosation (3.6 × 10–4 dm3 mol–1 s–1) obtained at pH 3 in unbuffered medium indicate that the rate of nitrosation of the amino group is one order of magnitude larger than that for the phenolic group.

Article information

Article type
Paper

J. Chem. Soc., Perkin Trans. 2, 1993, 2265-2273

Simultaneous C- and N-nitrosation of synephrine. A kinetic study

M. P. Fernández-Liencres, F. Carazo, M. C. Cabeza, B. Quintero, J. Thomas and J. M. Alvarez, J. Chem. Soc., Perkin Trans. 2, 1993, 2265 DOI: 10.1039/P29930002265

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