- Conversion of 5-hydroxymethylfurfural into 6-(hydroxymethyl)pyridin-3-ol: A pathway for the formation of pyridin-3-ols in honey and model systems
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The formation of 6-(hydroxymethyl)pyridin-3-ol by ring expansion of 5-(hydroxymethyl)furfural (HMF) in the presence of ammonia-producing compounds was studied to determine the routes of formation of pyridin-3-ols in foods. 6-(Hydroxymethyl)pyridin-3-ol was produced from HMF in model systems, mostly at neutral pH values, as a function of reaction times and temperature and with an activation energy (Ea) of 74 ± 3 kJ/mol, which was higher than that of HMF disappearance (43 ± 4 kJ/mol). A reaction pathway is proposed, which is general for the formation of pyridin-3-ols from 2-oxofurans. Thus, it explains the conversions of furfural into pyridin-3-ol and of 2-acetylfuran into 2-methylpyridin-3-ol, which were also studied. When honey and sugarcane honey were heated, they produced different pyridin-3-ols, although 6-(hydroxymethyl)pyridin-3-ol was the pyridine-3-ol produced to the highest extent. Obtained results suggest that formation of pyridin-3-ols in foods is unavoidable when 2-oxofurans are submitted to thermal heating and ammonia (or ammonia-producing compounds) is present.
- Hidalgo, Francisco J.,Lavado-Tena, Cristina M.,Zamora, Rosario
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p. 5448 - 5454
(2020/06/08)
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- Tetrabutylammonium phthalimide-N-oxyl: An efficient organocatalyst for trimethylsilylation of alcohols and phenols with hexamethyldisilazane
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Tetrabutylammonium phthalimide-N-oxyl (TBAPINO) was found to be an effective organocatalyst for rapid, simple and chemoselective protection of the hydroxyl group of alcohols and phenols using hexamethyldisilazane (HMDS) under mild conditions. The low catalyst loading, high to quantitative yields and simple removal of the catalyst from the reaction mixture illustrate the other attractive features of this protocol.
- Dekamin,Yazdaninia,Mokhtari,Naimi-Jamal
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experimental part
p. 537 - 544
(2012/06/18)
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- Silica sulfate, an efficient catalyst for the trimethylsilylation of alcohols
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An easy method for the preparation of trimethylsilyl ethers from alcohols and 1,1,1,3,3,3-hexamethyl-disilazane (HMDS) using silica sulfate as a catalyst under mild conditions in excellent yields is described. Copyright Taylor & Francis Group, LLC.
- Jin, Tong-Shou,Tian, Ruo-Fei,Liu, Li-Bin,Zhao, Ying,Li, Tong-Shuang
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p. 1823 - 1828
(2007/10/03)
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- Phosphomolybdic acid, an efficient catalyst for the trimethylsilylation of alcohols
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An easy method for the preparation of trimethylsilyl ethers of alcohols with 1,1,1,3,3,3-hexamethyl- disilazane (HMDS) catalysed by phosphomolybdic acid (PMA) under mild conditions has been carried out in excellent yields.
- Jin, Tong-Shou,Li, Yan-Wei,Sun, Guang,Li, Tong-Shuang
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p. 456 - 458
(2007/10/03)
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