Issue 20, 2021

How is vitamin B1 oxidized to thiochrome? Elementary processes revealed by a DFT study

Abstract

The oxidation reaction of thiamine (vitamin B1) to thiochrome was investigated by DFT calculations. Three reaction systems, [A] thiamine + methyl peroxy radical + (H2O)8, [B] thiamine + cyanogen bromide + HO(H2O)8 and [C] thiamine + mercury(II) chloride + HO(H2O)8, were investigated. wB97X-D/6-311+G** for [A] and [B] and wB97X-D/SDD&6-311(+)G** for [C] geometry optimizations were carried out with the solvent effect (water). The effect is of the self-consistent reaction field (SCRF) with the polarizable continuum model (PCM). In [A], the H3C–O2˙ adduct of thiamine undergoes simultaneous cleavage of the C–H and O–O bonds, leading to a very stable 2(3H)-thiazolone intermediate. The same intermediate was obtained after the cleavage of the C–H and O–H bonds of the HO adduct of thiamine in [B] and [C]. After the formation of the key intermediate, the N-protonated thiochrome was afforded via three steps. In reflection of the water-soluble character of vitamin B1, proton transfers along hydrogen bonds of the water cluster enhance those steps.

Graphical abstract: How is vitamin B1 oxidized to thiochrome? Elementary processes revealed by a DFT study

Supplementary files

Article information

Article type
Paper
Submitted
07 avr. 2021
Accepted
23 avr. 2021
First published
26 avr. 2021

Org. Biomol. Chem., 2021,19, 4529-4536

How is vitamin B1 oxidized to thiochrome? Elementary processes revealed by a DFT study

S. Yamabe, N. Tsuchida and S. Yamazaki, Org. Biomol. Chem., 2021, 19, 4529 DOI: 10.1039/D1OB00677K

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements