4- Hydroxy cinnamic acid

Propenoio acid, 3-(3-hydroxy-4-methoxyphenyl)- cinnamic acid, 3-hydroxy-4-methoxy- ferulic acid The following numerous reports describe the identification of the cis- or trans- isomers of ferulic add 3712 ... 

Coumarin is usually prepared by heating salicylaldehyde with acetic anhydride and sodium acetate (i.e., the Perkin cinnamic acid synthesis, p. 23 6), whereby the 0" hydroxy-cinnamic acid (I) undergoes cyclisation to coumarin. Coumarins having substituents in the benzene ring can often be similarly prepared. 

Another potentially valuable method for the preparation of cinnamic acid involves treatment of benzaldehyde with ketene (12). The initially formed oligomer of P-hydroxy-P-phenylpropionic acid is thermally decomposed at 100—250°C in the presence of an acid or base catalyst. 

Hydrolysis. The lactone is easily hydroly2ed by alkaUes to the corresponding salts of coumarinic acid or o-hydroxy-i j -cinnamic acid [495-79 ]. Coumarinic acid salts are odorless. Coumarinic acid and salts revert to coumarin upon acidification with inorganic acids. Alkaline fusion of coumarin yields salts of sahcyhc and acetic acids. 

Recent scientific investigations of natural polyphenols have demonstrated their powerful antioxidant property (Niki et al, 1995). Several classes of polyphenols have been chemically identified. Some of these are grape polyphenols, tea polyphenols, soy polyphenols, oligomeric proanthocyanidines (OPA) and other natural polyphenols of the flavone class. Rice bran polyphenols are different from the above in that they are p-hydroxy cinnamic acid derivatives such as p-coumaric acid, ferulic acid and p-sinapic acid. Tricin, a flavone derivative, has also been isolated from rice bran. 

RsHt Cinnamic Acid Rz 0Ht p- Hydroxy -cinnamic Acid (p -Coumanc Acid)... 

For PMMA/additive dissolutions, it was not possible to identify any additive characteristic mass peaks, either by direct laser desorption or with matrix-assistance (dithranol, DHBA or sinapinic acid, 4-hydroxy-3,5-dimethoxy-cinnamic acid). This has again been ascribed to very strong interaction between PMMA and additives, which suppresses desorption of additive molecules. Also, partial depolymerisation of pho-tolytically labile PMMA by laser irradiation may play a role, which leads to saturation of the detector by PMMA fragment-ions and disappearance of additive mass peaks below noise level. Meyer-Dulheuer [55] has also reported MALDI-TOFMS analysis of a coating/2-ethylhexyldiphenylphosphate sample. Quantitative determination of the additives by means of MALDI-ToFMS proved impossible. Possibly the development of reproducible (automated) sample handling procedures or thin films might overcome this problem. 

The benzoic acid, the acid moiety found in cocaine (98), is also derived from phenylalanine (141). Feeding of [4-3H]phenylalanine to E. coca led to the benzoyl moiety, where 96% of the 3H was located at the para position (138). The intermediacy of cinnamic, 3-hydroxy-3-phenylpropionic, and benzoylacetic acid in the formation of benzoic acid has been suggested (138). 

Hydroxy cinnamic acids are included in the phenylpropanoid group (C6-C3). They are formed with an aromatic ring and a three-carbon chain. There are four basic structures the coumaric acids, caffeic acids, ferulic acids, and sinapic acids. In nature, they are usually associated with other compounds such as chlorogenic acid, which is the link between caffeic acid and quinic acid. 

Murga R, Sanz MT, Beltran S and Cabezas JL. 2003. Solubility of three hydroxy cinnamic acids in supercritical carbon dioxide. J Supercrit Fluids 27(3) 239-245. 

Hexadiyne-l,6-dioic acid, 2094 4-Hydroxy-/rans-cinnamic acid, 3136 4-Hydroxy-3,5-dinitrobenzenearsonic acid, 2220 /V-Hvdroxvdithiocarbamic acid, 0454... 

Matrix assisted laser desorption ionization time-of-flight (MALDI-TOE) mass spectrometry was carried out with a PerSeptive Biosystems Voyager-DE-RP MALDl-TOF mass spectrometer. A 337-nm UV nitrogen laser producing 3-ns pulses was used in the reflectron mode. The samples were prepared by mixing 10 pi of a 0.1 M HAc solution of the sample with 20 pi of a solution of 3 mg/1 a-cyano-4-hydroxy cinnamic acid in wafer. One pi of that solution was loaded on the gold-sample plate. 

Hexadienal, 2383 t Hydrogen cyanide, 0380 4-Hydroxy-iranx-cinnamic acid, 3136 A-Hydroxymethylacrylamide, 1571 Methacrylic acid, 1530 I Methyl acrylate, 1531 I 2-Methylaziridine, Acids, 1257 I Methyl methacrylate, Propionaldehyde, 1915 3-Methyl-2-penten-4-yn-l-ol, 2384... 

There are several examples in the literature where similar cis-trans isomerizations of o-hydroxy cinnamic acid derivatives have been used to deliver fragrances. For example, ester 76, which was absorbed into cloth and exposed to sunlight, released its fragrant alcohol moiety, whereas samples that were stored in the dark did not... 

CS133 Imperato, F. N-P-coumarylglutamic acid, an unusual hydroxy cinnamic acid-aminoacid derivative from black CS143 tea. Chem Ind (London) 1980 388. 

DC040 Sarkar, S., and C. T. Phan. Some hydroxy-cinnamic acids of the carrot root. Plant Sci Lett 1974 2 41. 

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