Synthesis Of Cinnamate Research Articles

Molecular volume-controlled shape-selective catalysis for synthesis of cinnamate over microporous zeolites

On account of the safety and environmental problems arose from the inorganic acids use in the traditional cinnamate synthesis technology, developing eco-friendly solid-acid catalysts with low cost, high efficiency and recyclability is indispensable in cinnamate synthesis. Due to the unique shape-selective catalysis and diverse acidic properties of microporous zeolites, three different solid acid formulations including H-ZSM-5, H-Y and H-β are selected as catalysts and applied in catalytic synthesis of cinnamate. The effect of acidic property and pore structure on the performance of esterification of cinnamic acid with alcohols is emphatically investigated for three different zeolites after optimizing the catalytic reaction conditions. H-β zeolite exhibits the highest catalytic activity among three zeolites in the esterification of cinnamic acid with ethanol, owing to its strongest acidic property and largest pore channel. Taking account of the different structural properties of three microporous zeolites, it is considered that the pore size plays a dominant role in the synthesis of cinnamate. Furthermore, H-β zeolite always shows the highest catalytic activity coupled with the outstanding recyclability and regeneration efficiency, even in the condition of different alcohols used in cinnamate esterification reaction. It is found that the conversion of cinnamic acid is closely related to the molecular volume of intermediates and product molecules from experiment data and theoretical calculation. Specifically, the smaller molecular volume of intermediates and product molecules inclines to obtain the higher conversion of cinnamic acid and vice versa, which can be well explained from the perspective of mass transfer efficiency. It demonstrates that the activity of esterification reaction for cinnamic acid over H-β zeolite is dominantly associated with molecular volume of intermediates and product molecules. The research work provides a successful paradigm for microporous zeolite in shape-selective catalytic synthesis of cinnamate controlled by molecular volume.

Molecular Volume-Controlled Shape-Selective Catalysis for Synthesis of Cinnamate Over Microporous Zeolites

Molecular Volume-Controlled Shape-Selective Catalysis for Synthesis of Cinnamate Over Microporous Zeolites

ChemInform Abstract: An Efficient Sequential One‐Pot Base‐Mediated C—O and Pd‐Mediated C—C Bond Formation: Synthesis of Functionalized Cinnamates and Isochromenes.

AbstractThe one‐pot synthesis of cinnamates (III) from ortho‐bromobenzyl alcohols and olefins (II) involves sequential oxy‐Michael addition and intramolecular Heck coupling.

Depigmenting activity of new kojic acid derivative obtained as a side product in the synthesis of cinnamate of kojic acid

We synthesized cinnamate derivatives of kojic acid for use as depigmenting agents by various esterification methods. The cinnamate of 5-position of kojic acid (6) was obtained by EDC coupling, DCC coupling, acid chloride, and mixed anhydride methods. To obtain the cinnamate of the 2-position of kojic acid (7), we carried out the nucleophilic addition of the potassium salt of cinnamic acid to kojyl chloride. In this reaction, we discovered the occurrence of a side reaction and identified the structure of the side product thus formed. We evaluated the depigmenting activities of both the side product and the cinnamate derivatives of kojic acid. Interestingly, the side product (11) showed more potent depigmenting activity (IC50=23.51μM) than compound 7 (IC50>100μM) which is the mother compound of the side product. However, it has no tyrosinase inhibitory activity. Compound 6, the cinnamate of 5-position of kojic acid, also showed moderate depigmenting activity (IC50=46.64μM) without tyrosinase inhibitory activity. Production of this side product (11) may have originated from the proton exchange between the potassium salt of cinnamic acid and kojyl chloride. We then efficiently reduced the yield of the side product by controlling the equilibrium of the potassium salt of cinnamic acid. The addition of cinnamic acid greatly reduced the amount of the side product produced.

Gem-Dibromomethyl Aromatics: Efficient Aldehyde Equivalents in the Knoevenagel-Doebner Reaction

A valuable variation of the Knoevenagel-Doebner reaction for the efficient synthesis of cinnamic esters is described. This reaction provides cinnamic esters in a single step from gem-dibromomethyl aromatics, which otherwise require the hydrolytic conversion of gem-dibromides into aldehydes, and demonstrates the use of an alternative reagent for noncommercial and expensive aldehydes. Further, the reaction of gem-dibromomethyl aromatics with malonic acid and di-tert-butyl dicarbonate for the one-pot synthesis of tert-butyl cinnamates is also described.

Metabolisme des composes phenoliques chez le petunia v. utilisation de la phenylalanine par des chloroplastes isoles

The involvement of plastids in phenolic metabolism has been studied in Petunia after an isolation method of pure and physiologically intact chloroplasts has been adapted. Feeding experiments with [ 14C] phenylalanine demonstrated in these isolated organelles: the synthesis of cinnamate and benzoate derivatives which, with the exception of the first term of each serie, are o-hydroxylated ( o-coumaric acid, coumarin and salicylic and gentisic acids); the lack of formation of labelled p-hydroxylated derivatives and flavanoids. The results are in agreement with the characterization, in the plastids of specific enzymes (PAL, cinnamate-2-hydroxylase) and the absence of cinnamate-4-hydroxylase. All these data suggest that the formation of p-hydroxylated derivatives, esters and flavonoids often characterized in chloroplasts may involve a cooperation between different organelles.