E-methyl ferulate

The mode of fragmentation of the original propenoidic chain was further investigated using an ester of ferulic acid, e.g. E-methyl ferulate 11, as the starting material in the same reaction sequence. The oxidation was repeated at room temperature in methanol using R = 10, Pdioxygen= t = 72 h the reaction... 

The oxidation of E-methyl ferulate 11 was faster in chloroform than in methanol. In pyridine a very slow reaction was observed (Table II). 

Table L Product Yields % in the Reaction of E-Ferulic Acid 1 and E-Methyl Ferulate 11 with Co(II)salen-dioxygen. ...

Table IL Conversion vs Time in the Oxidation of E-Methyl Ferulate 11 with ...

Figure 2. The EPR Signal in the Reaction of E-Methyl ferulate 11 in Chloroform.

The second p-5 dimer studied, the trans dimer 27, was obtained from E-methyl ferulate (23). The oxidation with dioxygen (10 bar) in methanol in the... 

The propenoidic phenols, E-methyl ferulate (1), E-4-hydroxycinnamic acid me yl ester (4) and E-3-chloro-4-hydroxycinnamic acid methyl ester (7), can be catalytically oxidized with dioxygen in the presence of [Co(salen)] (Figure 8) . The yields depend on the solvent and the phenyl substituents. EPR and electronic spectra suggest the involvement of a coordinated o-benzosemiquinone type radical as the active intermediate. 

Good reproducibility can be expected. Figure E3.4.3 shows chromatograms of acetic acid and methanol standards and a pectin sample. Additional peaks are observed in the HPLC traces (Figure E3.4.3C). These are presumably due to other alcohols and acids (e.g., ferulic acid Renard and Thibault, 1993) released by alkaline treatment. Table E3.4.2 shows the degrees of methylation and acetylation of pectin samples. 

Five transformants produced a major secreted protein band, with an estimated molecular weight of 40 kDa and no protein was detected in the control. The estimated molecular weight is greater than that predicted or observed from E. coli, which is likely due to post-translational modification. P6 and P10 transformants were retained to perform enzymatic assays. The culture supernatants were assays for activity against methyl caffeate (MCA) and methyl ferulate (MFA). The recombinant proteins were shown to be active as a feruloyl esterase and show the characteristics of a type B ferulic acid esterase.6 Feruloyl esterase activity is reported in Table 1. 

Occurrence in the Solanaceae. p-Coumaric acid, caffeic acid, methyl caffeate, and methyl ferulate as well as certain of their 2,3-dihydro derivatives have been identified as constituents of the leaves of Cestrum parqui L Herit. with good phytotoxic activity against different species (D Abrosca et al. 2004). Family-specific phenylpropanoid acids like tropic acid or 2-hydroxytropic acid as acyl moieties of tropane alkaloids are synthesized via phenylalanine -> phenylpyruvic acid (l )-3-phenyllactic acid (Fig. 3.14 Table 3.1 (T5-T7-B)]. Tropic acid may occur as a metabolite of, e.g., hyoscyamine, but the free acid is not synthesized as such (for details see Sect. 3.4). 

A series of subsequent reactions after PAL first introduces a hydroxyl at the 4-position of the ring of cinnamic acid to form p- or 4-coumaric acid (i.e., 4-hydroxycinnamic acid). Addition of a second hydroxyl at the 3-position yields caffeic acid, whereas O-methylation of this hydroxyl group produces ferulic acid (see Fig. 3.3). Two additional enzymatic reactions are necessary to produce sinapic acid. These hy-drocinnamic acids are not found in significant amounts in plant tissue because they are rapidly converted to coenzyme A esters, or glucose esters. These activated intermediates form an important branch point because they can participate in a wide range of subsequent reactions. 

Propenoic acid, homopolymer, ammonium salt. See Ammonium polyacrylate 2-Propenoic acid, homopolymer, sodium salt. See Sodium polyacrylate 2-Propenoic acid, 2-hydroxyethyl ester. See 2-Hydroxyethyl acrylate 2-Propenoic acid, 3-(4-hydroxy-3-methoxyphenyl)-. See Ferulic acid 2-Propenoic acid-2-(hydroxymethyl)-2-(((1 -oxo-2-propenyl) oxy) methyl)-1,3-propanediyl ester. See Pentaerythrityl triacrylate 2-Propenoic acid, 3-(2-hydroxyphenyl)-, (E)-. 

Veratraldehyde 3 and veratric acid methyl ester 4 were isolated from vanillic aldehyde 5 and vanillic acid methyl ester 6 in the original reaction mixture. Silica gel chromatography of this reaction mixture was used to isolate small amounts of these primary oxidation products. These compounds had lost two carbon atoms from the origind propenoidic chain. A further component isolated from the methylated mixture was 2-methoxyhomoveratric aldehyde 7, which suggested the presence of 2-hydroxyhomoveratric aldehyde 8 in the oxidation reaction mixture. Its structure was confirmed by independent synthesis. Treatment of the reaction mixture from the catalytic oxidation of E-ferulic acid 1 with 1,3-dithiane followed by methylation formed the thioketal 9, which was also prepared by reaction of veratraldehyde 3 with 1,3-dithiane carbanion 10 followed by methylation. 

Conversion Studies The appropriate amount of catalyst was added to 50 mL of a 10"2 M solution of E-Ferulic acid 1 in methanol and the resulting solution was put in a 250 ml autoclave which was then charged with 10 bar of dioxygen. After 72 h at room temperature, the suspension was filtered and the solvent was evaporated under reduced pressure at room temperature. The residue was dissolved in 10 mL of methanol, methylated with excess ethereal diazomethane, filtered on a silica gel column and analyzed in GC using biphenyl as the internal standard. 

The action of catechol O-methyl transferase might be a central metabolic event after the absorption of free caffeic acid or some of its metabolites with a still intact catechol moiety, such as dihydrocaffeic acid or protocatechuic acid. In most studies administering chlorogenic acid or preparations rich in caffeic acid derivatives (i.e., coffee), only 0-methylated metabolites but no metabolites with an intact catechol group were detected in urine, supporting the central role of 0-methylation of caffeic acid post absorption [6,17,18]. Studying the O-methylation of caffeic acid in vitro by using rat or rabbit liver slices or preparations of liver, both possible O-methylation products, ferulic and iso-femlic acids, were formed, and a meta/para ratio of 2.8 1 was recorded [13]. In addition, the ability to reduce the residual double bond was also observed in vitro with rat or rabbit liver slices [10]. 

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