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Author: Subject: Preparation of Crude 2-Hydroxy-5-Methoxybenzaldehyde. Methanol?
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biggrin.gif posted on 11-6-2021 at 12:50
Preparation of Crude 2-Hydroxy-5-Methoxybenzaldehyde. Methanol?


Hi, this about patent
https://patents.google.com/patent/US6670510B2/en
“ Example 1 Preparation of Crude 2-Hydroxy-5-Methoxybenzaldehyde.
A mixture of 600 g of acetonitrile, 186.2 g of 4-methoxyphenol (1.5 moles) and 214 g (2.25 moles) of anhydrous magnesium chloride was warmed to 45° C. and 227.4 g (2.25 moles) of triethylamine was added dropwise at that temperature. Paraformaldehyde (150 g, 4.75 moles) was then added and the reaction was heated to reflux. Methanol was removed over 3 hours by distillation, using a 10-inch column packed with Penn-State packing. “

Where does methanol come from? Of the reaction? Forgot to add it at the beginning?

De donde sale el metanol? De la reacción? Se han olvidado añadirlo al principio?.

Thanks
Joaquin
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[*] posted on 11-6-2021 at 12:56


Reduction of the formaldehyde, I suppose.
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[*] posted on 11-6-2021 at 13:57


This looks like a similar reaction to the Casiraghi formylation, whose mechanism and scope are detailed here:
https://sci-hub.se/10.1039/P19800001862

If that link doesn't work directly, the paper is Selective reactions between phenols and formaldehyde. A novel route to salicylaldehydes. Journal of the Chemical Society, Perkin Transactions 1, 1862. doi:10.1039/p19800001862
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