The mechanism and the final outcome of the Knoevenagel-Doebner reaction are discussed. The condensation reaction between different hydroxy-substituted aromatic aldehydes and malonic acid is performed using piperidine as organocatalyst. The key role of the catalyst is clearly pointed out during the decarboxylation of ferulic acid, without the use of a strong decarboxylating agent, leading to a 4-vinylphenol derivative. Based on the results obtained, the studied pathway may be important in the understanding of vinylphenol production during malting and brewing of wheat and barley grains. Finally, changing the solvent of the reaction from pyridine to water in the Knoevenagel-Doebner reaction of 4-hydroxybenzaldehydes, dimerization of resulting styrene derivatives is observed. These results can be of interest also in the field of food chemistry, since cinnamic acids are frequently found in fruits and vegetables used for human consumption

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The enzymatic reduction of prochiral heterocyclic ketones by carrot (Daucus carota) root in water afforded the corresponding S-alcohols in accordance with the Prelog's rule. The reaction was performed under various conditions in order to optimize the procedure of bioreduction regarding reaction time, yield, and optimal mass of carrot. The optimized procedure was used to test the ability of other plants to carry out the reaction. In the latter experiment, it was observed that, with regard to stereospecificity, most vegetables tested were poorer reducing agents compared to D. carota.

The crystal structure of divainillin (systematic name: 6,6′-dihydroxy-5,5′-dimethoxy-[1,1′-biphenyl]-3,3′-dicarbaldehyde), C16H14O6, was determined from laboratory powder X-ray diffraction data using the software EXPO2013 (direct methods) and WinPSSP (direct-space approach). Divanillin molecules crystallize in the orthorhombic space group Pba2 (No. 32), with two molecules per unit cell (Z′ = 1 \over 2). Each divanillin molecule, with twofold symmetry, is linked through strong alcohol–aldehyde hydrogen bonds to four equivalent molecules, defining a three-dimensional hydrogen-bonding network, with rings made up of six divanillin units (a diamond-like arrangement). Each molecule is also connected through π–π interactions to a translation-equivalent molecule along c. Four consecutive molecules stacked along [001] belong to four different three-dimensional hydrogen-bonding networks defining a quadruple array of interpenetrating networks. This complex hydrogen-bonding array is proposed as an explanation for the aging process experienced by divanillin powders.