2.4- Dihydroxy cinnamic acid

Caffeic acid (3,4-dihydroxy cinnamic acid) +0.4 glassy carbon 268 85... 

Ananas comosus (L.) Merrill Feng Li (leaf) Ergosterol peroxide, ananasic acid, 5 -stigmautena-3 (3,7d-diol, 3,4-dihydroxy cinnamic acid, 4-hydroxycinnamic acid, bromelin, vitamins.57 Antioxidant activity, for digestion, lower blood pressure, anticancer. 

The high activity observed for caffeic acid was further investigated by studying the activity of a number of related compounds, in order to determine structure-activity relationships. Table II compares the activities of mono-hydroxycinnamic acids to caffeic acid (3,4-dihydroxy-cinnamic acid). All of the mono-hydroxy acids were more active than caffeic acid. o-Hydroxycinnamic (o-coumaric) acid was the most active and gave 91% inhibition of fungal growth at only 62.5 ppm. 

Synonyms Benzenepropanoic acid, a-[[3-(3,4-dihydroxyphenyl)-1 -oxo-2-propenyl] oxy]-3,4-dihydroxy- Benzenepropanoic acid, o-[[(3,4-dihydroxyphenyl)-1 -oxo-2-propenyl] oxy]-3,4-dihydroxy- Cinnamic acid, 3,4-dihydroxy-, 2-ester with 3-(3,4-dihydroxyphenyl) lactic acid 3,4-Dihydroxycinnamic acid 2-ester with 3-(3,4-dihydroxyphenyl) lactic acid R-(+)-2-(3,4-Dihydroxycinnamoyloxy)-3-(3,4-dihydroxyphenyl) propionic acid a-[[(3,4-Dihydroxyphenyl)-1-oxo-2-propenyl] oxy]-3,4-dihydroxybenzenepropanoic acid Rosemary acid Rosmarinate Classification Naturally occurring polyphenolic compd. 

Kaneko et al. [79] have prepared hyperbranched structures from the copolymerization of 4-hydroxycinnamic acid with 3,4-dihydroxy cinnamic acid i.e. monomers bearing some resemblance to lignin structural units). These... 

Esters of 4-hydroxy- and 3,4-dihydroxy-cinnamic acid have been found in two new D-glucosides isolated from the leaves of Nandina domestica Thunb. The synthesis of optically active derivatives of truxinic acids by photolysis of cinnamoyl esters of D-mannitol is reported in Chapter 28. 

Figure 14.6 Structures of some commonly used MALDI matrices (a) 2,5-dihydroxy benzoic acid (DHB), (b) a-cyano-4-hydroxy-cinnamic acid, and (c) sinapinic acid (SA). Combination of these acidic MALDI matrices with organic bases leads to the formation of ionic liquid matrices.

The olive mesocarp contains a number of phenolic and polyphenolic compounds and their esters, small amounts of which are present in olive oil (35, 43, 44). These include monohydroxy- and dihydroxy-phenylethanol, including tyrosol and other phenols and a series of carboxy-phenols, including caffeic, o-coumaric, p-coumaric, cinnamic, ferulic, gallic, p-hydroxybenzoic, protocatechuic, sinapic, syringic, and vanillic acids. Benzoic and cinnamic acids are produced by hydrolysis of flavonoids. The hydroxyphenyl-ethanols arise from hydrolysis of oleoeuropein. Their esters are responsible for the bitterness and pepperlike sensation occasionally dominant in the taste of olive oils. 

Certain crystal structures, however, that appear to fit the criteria just listed for a or /3 cinnamic acids do not, in fact, produce photodimers. For example, 3,4-dihydroxy-traras-cinnamic acid is photostable.It is suggested that this is because symmetry-related molecules are held together by strong hydrogen bonding which does not permit the molecular flexibility that requires the 4.0 A interaction to be reduced to approximately 1.5 A. It appears that there needs to be sufficient space in the crystal reaction cavity for the reaction to take place, and sufficient flexibility in the overall crystal packing for the required atomic spatial reorganization to occur. 

Garcia-Granda, S., Beurskens, G., Beurskens, P. T., Krishna, T. S. R., and Desiraju, G. R. Structure of 3,4-dihydroxy-frnns-cinnamic acid (caffeic acid) and its lack of solid-state topochemical reactivity. Acta Cryst. C43, 683-685 (1987). 

Sinapinic acid Alpha-c ano-4-hydroxy 2,5-dihydroxy MW 224.07 amu cinnamic acid benzoic acid... 

Cinnamic acid, 3,4-dihydroxy- caffeic acid 49. Phenol, 2-methyl- o-cresol... 

Phenolic acid derivatives (cinnamic acids) and degradation products of flavonoids (phenylpropionic and phenylacetic acids) suffer transformations by caecal bacteria. The following transformations have been observed dehydroxylation of 3,4-dihydroxy derivatives to give 3-hydroxy compounds, demethylation of o-hydroxy-methoxyphenolic acids, reduction of the double bonds of cinnamic acids to yield the corresponding phenylpropionic acids, decarboxylation of cinnamic and phenylacetic acids (only when 4-hydroxyl is present), hydroxylation of... 

Norwood et al. (1980) chlorinated a considerable number of phenolic acids of both benzoic and cinnamic acid types and looked for haloform production. Concentrations were from 0.5-6 mM and approximately a twofold excess of chlorine was added. For most of the acids tested, except those with 1,3-dihydroxy (resorcinol-type) substituents, chloroform yields were low (0-4 7o) except in the case of 3-methoxy-4-hydroxycinnamic acid (ferulic acid, 10), where about an 11% yield was... 

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