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Oligomerization Products from Thiamin in Methanol

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Title:Oligomerization Products from Thiamin in Methanol
Authors:Nishida, Clinton
Contributors:Chemistry (department)
Date Issued:15 Jan 2014
Publisher:University of Hawaii at Manoa
Abstract:In 1974, Shimahara, et al. [1 ] discovered that thiamin (vitamin B1 ) monochloride decomposes in alcohol solution, a reaction which cannot be accounted for solely on the basis of the known instability of thiamin in alkaline solution [2]. Of methanol, ethanol, and propanol, reaction in methanol led to the fastest decomposition rate. Reaction temperature, pH of the solution, and thiamin concentration affected the rate of reaction. For all alcohols, one of the products was determined by IR and NMR spectroscopy to be 5-(2-hydroxyethyl)-4-methyl-thiazole, the thiazole moiety of thiamin. The other product was a crystalline compound designated compound (X), or compound (X') if converted to the nitrate using silver nitrate. Initially believed to be the pentamer nitrate, penta-methi(1 ,4-dihydro-4-imino- 2-methyl-pyrimidinylen-1 ,5-amer nitrate (Fig. 1 a), based on NMR and mass spectral data, compound (X') has since been determined, via single crystal x-ray diffraction, to be the cyclic hexamer (Fig. 1 b, 2) by the Cramer group [4]. The cyclic tetramer has since been isolated and characterized as well (Fig. 1b) [5].
Pages/Duration:ix, 92 pages
Rights:All UHM Honors Projects are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.
Appears in Collections: Honors Projects for Chemistry

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