Vanillin Synthesis from 4-Hydroxybenzaldehyde

Abstract

A simple and safe preparation of vanillin from 4-hydroxybenzaldehyde is described. This synthesis is appropriate for undergraduate organic chemistry laboratory courses.

Synthesis and elucidation of deuterated vanillylamine hydrochloride and capsaicin

“…Overall yield of [ 2 H 3 ]vanillylamine hydrochloride ( 5 ) from ( 2 ) was about 9.6%. 3‐Bromo‐4‐hydroxybenzaldehyde ( 2 ) was prepared from 4‐hydroxybenzaldehyde ( 1 ) using a reported procedure 7. It was found that the optimum reaction time for this bromination was 30 s to 1 min.…”

“…It was found that the optimum reaction time for this bromination was 30 s to 1 min. Longer reaction times resulted in the formation of 3,5‐dibromo‐4‐hydroxybenzaldehyde or conversion back to starting material 7. Conveniently, the crude reaction mixture could be used immediately in the next step.…”

Unprecedented Formation of 2,5‐Diaminoquinones from the Reaction of Vanillin with Secondary Amines in Aerobic Conditions

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Vanillin is widely used as a flavoring agent in foods, perfumes and in several other applications. Vanillin is commonly synthesized using guaiacol, eugenol [2][3][4] or 4-hydroxybenzaldehyde [5] as starting materials or can be also easily prepared starting from different molecules (often from ferulic acid or eugenol), following different enzymatic/microbial routes, [6,7] allowing to fulfil the market demand. In this context, we observed the formation of orange to red crystalline compounds Vanillin (4-hydroxy-3-methoxybenzaldehyde) is one of the most important flavoring compounds used in foods, beverages, food supplements, perfumes and pharmaceuticals.

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“…However, being the extraction very expensive and covering just a little percentage of the market request, synthetic vanillin (or more recently "ethylvanillin", 3-ethoxy-4-hydroxybenzaldeyde, "bourbonal", characterized by a stronger and persistent aroma) is nowadays the most used by industry. Vanillin is commonly synthesized using guaiacol, eugenol [2][3][4] or 4-hydroxybenzaldehyde [5] as starting materials or can be also easily prepared starting from different molecules (often from ferulic acid or eugenol), following different enzymatic/microbial routes, [6,7] allowing to fulfil the market demand. The annual worldwide consumption of vanillin exceeds 16,000 tons, even if the estimation of consumed vanillin originated from vanilla pods is only about 0.25 %.…”

Salicylaldehyde Hydrazones: Buttressing of Outer-Sphere Hydrogen-Bonding and Copper Extraction Properties

“…[50] The methoxysubstituted salicylaldehyde (5) was prepared from its bromo analogue 4 by a modification of the literature method. [51] In the case of 3-methyl-salicylaldehyde (2), the synthesis exploited the modified Duff reaction [52] starting with 4-tert-butyl-2-methylphenol, since it was commercially available and it would be difficult to methylate 1 by Friedel-Crafts or related reactions. X-ray structure determinations of L6 and L10 (Figure 4) reveal that, as expected, the phenolic group acts as an intramolecular bond donor, O-H···N, to the imine nitrogen atom and as an intermolecular hydrogen bond acceptor from a hydrazone NH group in a neighbouring molecule.…”