Hedyotis diffusa Willd/Widespread in plants, e.g. peel of black cherry (Prunus serotina), lentil seeds and from red clover (Trifolium pratense) and Daviesia latifolia. Occurs as many glycosides. Found by Bate-Smith in 48% of investigated dicotyledonous and 55% of monocotyledon
4-Hydroxy cinnamic acid/(2E)-3-(4-Hydroxyphenyl)acrylic acid/trans-p-Cumaric Acid/3-(4-Hydroxy-phenyl)-acrylic acid/trans-p-Coumaric Acid/2-propenoic acid, 3-(4-hydroxyphenyl)-/E-4-Hydroxycinnamic Acid/(E)-3-(4-Hydroxyphenyl)acrylic acid/2-Propenoic acid, 3-(4-hydroxyphenyl)-, (2E)-/4-Coumaric acid/trans-4-Hydroxycinnamic Acid/p-Hydroxycinnamic acid,predominantly trans/4-Hydroxycinnamic acid
p-Coumaric acid is the abundant isomer of cinnamic acid which has antitumor and anti-mutagenic activities.
346.1±17.0 °C at 760 mmHg
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provides coniferyl ferulate(CAS#:501-98-4) MSDS, density, melting point, boiling point, structure, formula, molecular weight etc. Articles of coniferyl ferulate are included as well.>> amp version: coniferyl ferulate
The low-lying excited singlet states of trans-p-coumaric acid (CA) and trans-p-coumaric thio acid (CTA) are investigated in view of characterizing the chromophore of the photoactive yellow protein (PYP), with particular regard to the impact of sulfur on the chromophore’s electronic structure. The comparative ab initio study, performed with the highly accurate EOM-CCSD method, shows that the electronic state ordering upon vertical excitation and following in-plane geometry relaxation indeed depends in a very sensitive fashion on the presence of either sulfur or oxygen. The study identifies three relevant excited singlet states, two of which are of pi-pi type while the third state is of n-pi character. The study highlights the role of the latter n-pi state which is shown to be the lowest-lying excited state of CTA at all in-plane geometries under consideration, whereas this is not the case for CA.
Impact of sulfur vs oxygen on the low-lying excited states of trans-p-coumaric acid and trans-p-coumaric thio acid.
Gromov EV1, Burghardt I, Koppel H, Cederbaum LS.
2005 May 26
The photoisomerization of trans-p-coumaric acid (trans-CA) triggers a photocycle in photoactive yellow protein that ultimately mediates a phototactic response to blue light in certain purple bacteria. We have used fluorescence excitation and dispersed emission methods in a supersonic jet to investigate the nature of the electronic excited states involved in the initial photoexcitation and subsequent photoisomerization of trans-CA. We observed three distinct regions in the fluorescence excitation spectrum of trans-CA. Region I is characterized by sharp features that upon excitation exhibit trans-CA S(1) emission. In region II, features increase in width and decrease in intensity with increasing excitation energy. Upon excitation, we observed dual emission from the S(1) state of trans-CA and what may be the S(1) state of cis-CA. The onset of dual emission corresponds to an isomerization barrier of about 3.4 kcal/mol. Finally, the extremely broad absorption feature in region III is excitation to the S(2) electronic excited state and excitation results in trans-CA S(1) emission. Furthermore, we collected CA from the molecular beam after laser excitation in each of the three regions as further evidence of the photoisomerization process. The relative amounts of trans- and cis-CA in the collected molecules were measured with high-pressure liquid chromatography. Although trans-CA was excited in all three regions, a significant cis-CA peak appeared only in region II, though a small cis peak was observed in region III.
Gas-phase photochemistry of the photoactive yellow protein chromophore trans-p-coumaric acid.
Ryan WL1, Gordon DJ, Levy DH.
2002 May 29