3.4- Dihydroxycinnamate

On the basis of the obtained results and the literature[17-18], we assume that during the oxidative decomposition of p-coumaric acid 1, three kind of reaction can happen before the opening of the aromatic ring (Scheme 1) cleavage of the very reactive exocyclic double bond to give p-hydroxybenzaldehyde 2, hydroxylation of the aromatic ring to yield 3,4-dihydroxycinnamic acid 3 and oxidation of aldehydes to carboxylic acids such as oxidation of 2 to p-hydroxybenzoic acid 4. Compound 2 can be hydroxylated to yield 3,4- dihydroxybenzaldehyde 6. and Compound 4 can also be hydroxylated to yield 3,4-dihydroxybenzoic acid 5. 

Coumaric acid (or 4-hydroxycinnamic acid) R = H Caffeic acid (or 3,4-dihydroxycinnamic acid) R = OH Cinnamaldehyde... 

Ananas comosus (L.) Merrill China Ergosterol peroxide, ananasic acid, 5-stigmautena-3(3,7d-diol, 3,4-dihydroxycinnamic acid, 4-hydroxycinnamic acid, bromelin, vitamins.57 Antioxdant activity, for digestion, lower blood pressure, anticancer. 

The most common cinnamic acids are caffeic (3,4-dihydroxycinnamic acid), ferulic (3-methoxy-4-hydroxy), sinapic (3,5-dimethoxy-4-hydroxy) and p-coumaric (4-hydroxy) acid, Table 4 [13]. 

The phenolic acids of interest here [caffeic acid (3,4-dihydroxycinnamic acid), ferulic acid (4-hydroxy-3-methoxycinnamic acid), p-coumaric acid (p-hydroxycinnamic acid), protocatechuic acid (3,4-dihydroxybenzoic acid), sinapic acid (3,5-dimethoxy-4-hydroxyxinnamic acid), p-hydroxybenzoic acid, syringic acid (4-hydroxy-3,5-methoxybenzoic acid), and vanillic acid (4-hydroxy-3-methoxybenzoic acid)] (Fig. 3.1) all have been identified as potential allelopathic agents.8,32,34 The primary allelopathic effects of these phenolic acids on plant processes are phytotoxic (i.e., inhibitory) they reduce hydraulic conductivity and net nutrient uptake by roots.1 Reduced rates of photosynthesis and carbon allocation to roots, increased abscisic acid levels, and reduced rates of transpiration and leaf expansion appear to be secondary effects. Most of these effects, however, are readily reversible once phenolic acids have been depleted from the rhizosphere and rhizoplane.4,6 Finally, soil solution concentrations of... 

New drimane sesquiterpenoids include 6p-acetoxyisodrimenin (74), capsico-dendrin, a partially characterized tetramer of cinnamodial (63),45 albicanyl 3,4-dihydroxycinnamate (75), albicanyl 2,4-dihydroxycinnamate (76) (both liverwort constituents),48 and polyveoline (77), an indolosesquiterpenoid.47 Full details of the isolation and structural determination of pebrolide (78) and its congeners (79) and (80) have been published.48 The biosynthesis of pebrolide... 

Synonyms 3,4-Dihydroxycinnamic acid 3,4-Dihydroxybenzeneacrylic acid Source Murga, R. Sanz, M.T. Beltran,S. ... 

Soils also contain a number of low-molecular-mass water-soluble aromatic acids including benzoic, 4-hydroxybenzoic, cinnamic, coumaric (4-hydroxydnnamic), caffeic (3,4-dihydroxycinnamic), ferulic (3-methoxy-4-hydroxydnnamic), and vanillic (3-methoxy-4-hydroxybenzoic) acids. It has been shown that at plausible concentrations of these (< 100 gg/1) and at pH 5.6, there is competition between these and 2,4-dichlorophenol for sorption sites on soil organic matter (Xing and Pignatello 1998). 

The structure was proved by synthesis of a reference sample obtained by catalytic hydrogenation of dihydroxystyrene, itself prepared by decarboxylation of 3,4-dihydroxycinnamic acid (caffeic acid) according to Reichstein (1932). 

From the results of a study in which Kentucky reference IRl cigarettes were spiked with increasing levels of chlorogenic acid (the 3-ester of 3,4-dihydroxycinnamic acid with... 

Rubescine, also from A. rubescens, is the 3,4-dihydroxycinnamate of vincoside lactam, where the extra acyl residue is at the 3-position of the glucose unit. 

The ability of oxidation products of 3,4-dihydroxycinnamic acid to prevent the binding of TSH to human... 

Auf mkolk M, Amir SM, Kubota K, et al. The active principles of plant extracts with antithyrotropic activity oxidation products of derivatives of 3,4-dihydroxycinnamic acid. Endocrinology 1985 116 1677-1686. 

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