23790-80-9Relevant articles and documents
Human cellular retinaldehyde-binding protein has secondary thermal 9-cis-retinal isomerase activity
Bolze, Christin S.,Helbling, Rachel E.,Owen, Robin L.,Pearson, Arwen R.,Pompidor, Guillaume,Dworkowski, Florian,Fuchs, Martin R.,Furrer, Julien,Golczak, Marcin,Palczewski, Krzysztof,Cascella, Michele,Stocker, Achim
, p. 137 - 146 (2014)
Cellular retinaldehyde-binding protein (CRALBP) chaperones 11-cis-retinal to convert opsin receptor molecules into photosensitive retinoid pigments of the eye. We report a thermal secondary isomerase activity of CRALBP when bound to 9-cis-retinal. UV/vis and 1H NMR spectroscopy were used to characterize the product as 9,13-dicis-retinal. The X-ray structure of the CRALBP mutant R234W:9-cis-retinal complex at 1.9 A resolution revealed a niche in the binding pocket for 9-cis-aldehyde different from that reported for 11-cis-retinal. Combined computational, kinetic, and structural data lead us to propose an isomerization mechanism catalyzed by a network of buried waters. Our findings highlight a specific role of water molecules in both CRALBP-assisted specificity toward 9-cis-retinal and its thermal isomerase activity yielding 9,13-dicis-retinal. Kinetic data from two point mutants of CRALBP support an essential role of Glu202 as the initial proton donor in this isomerization reaction.
PHOTOISOMERIZATION OF THE C18 KETONE IN THE VITAMIN A SERIES. SOLVENT EFFECT ON PHOTOISOMERIZATION OF COMPOUNDS RELATED TO RETINAL
Ramamurthy, V.,Denny, M.,Liu, R. S. H.
, p. 2463 - 2466 (1981)
The directions of photoisomerization of polyenals and polyenones are believed to be controlled by the relative ordering of n,?* and ?,?* states.
Vinyltin acetals in terpenic and nor-terpenic synthesis
Launay, Valerie,Beaudet, Isabelle,Quintard, Jean-Paul
, p. 937 - 946 (2007/10/03)
Vinyltin acetals obtained by stannylmetallation of homopropargyl acetals with Bu3SnMgMe/CuCN (E configuration) or by titanation of the corresponding alkyltin acetals (Z configuration) have been proved to be efficient storable precursors for the stereoselective synthesis of terpenoids, under mild experimental conditions.Due to the presence of a nucleophilic centre (Csp2-Sn bond) and of a protected electrophilic centre, they are also useful intermediates for an iterative synthesis of retinal and nor-retinoids. - Keywords: vinyltin; acetal; vinyllithium; monoterpenoid; retinal; nor-retinoid
Palladium-catalysed vinylation of tertiary allylic alcohols: A new protocol for the synthesis of isoprenoid aldehydes.
Bienayme,Yezeguelian
, p. 3389 - 3396 (2007/10/02)
Heck vinylation of tertiary allylic alcohols with iodo-acetal Ic, followed by an acid catalysed acetal hydrolysis-dehydration reaction, furnished isoprenoid aldehydes regioselectively in high yields.
Retinal, derivatives and their therapeutic use
-
, (2008/06/13)
Therapeutic as well as preventive measures to improve cosmetic conditions and to alleviate the symptoms of dermatologic disorders with retinal and its derivatives is disclosed. Cosmetic conditions and dermatologic disorders in humans and domestic animals in which retinal and its derivatives may be useful include age spots, wrinkles, warts, eczema, seborrheic keratoses, acne, oily skin, psoriasis, dandruff, xerosis, inflammatory and pruritic skin, disturbed keratinization skin changes associated with aging and possibly viral infections. Retinal and its derivatives include their stereoisomers, for example, all-trans, 13-cis, 11-cis, 9-cis, 7-cis, 11,13-cis and 9,13-cis vitamin A aldehydes, their hydrate, hemiacetal and acetal forms, and their adduct compounds. Compositions containing retinal or its derivative may be administered systemically such as orally, or topically to the affected areas of the skin.
A new prenylation method using the lithium enolate of prenal. Reaction with polyunsaturated aldehydes. A short access to retinal
Duhamel, Lucette,Guillemont, Jerome,Poirier, Jean-Marie,Chabardes, Pierre
, p. 4499 - 4500 (2007/10/02)
The enolate of prenal 1 prepared from the corresponding silyl enol ether 2 or enol acetate 3 led to a γ-regiospecific reaction with polyunsaturated aldehydes 4 yielding dihydropyrans 5 leading after hydrolysis to polyenals 7. This process allows the introduction of the isoprenyl skeleton. A synthesis of retinal, from β-ionylidenacetaldehyde is reported.
Photoisomerization of Hindered Poly-cis Isomers of Retinal. Regioselectivity And One -Photon-Multiple-Bond Isomerization.
Ganapathy, Srinivasan,Liu, Robert S. H.
, p. 6957 - 6960 (2007/10/02)
Direct irradiation of five dicis (7,9, 7,11, 7,13, 9,11 and 9,13) and one tricis (7,9,11) isomers of retinal led to regioselective isomerization at the 13,14 bond as well as multiple-bond isomerization.
Sensitized photoisomerization of all-trans- and 11-cis-retinal
Jensen,Wilbrandt,Bensasson
, p. 7877 - 7888 (2007/10/02)
The photoisomerization of all-trans-retinal (all-trans) and 11-cis-retinal (11-cis) sensitized by a range of sensitizers (porphyrins, Zn-porphyrins, naphthacene and a Zn-phthalocyanine) with varying triplet energies above and below the vertical triplet energy of all-trans-retinal (E(T) = 149 kJ/mol) has been investigated by continuous illumination and HPLC analysis of the products. The composition of the photostationary states, the relative isomerization quantum yields of all-trans and 11-cis, and the primary product ratios are reported. One photon-one bond isomerizations are dominant. With Zn-TPP as sensitizer it is shown that 11-cis and possibly all-trans undergoes one photon-two bond isomerizations as well. The quantum yields of photoisomerization of 11-cis sensitized by biphenyl (E(T) = 275 kJ/mol) and anthracene (E(T) = 178 kJ/mol) were found to be identical. Absolute measurements allowed evaluation of the overall triplet isomerization quantum yield of 11-cis, Φ(iso)(T)(11-cis→) = 1.0 ± 0.2, from which the corresponding quantity for all-trans, Φ(iso)(T)(trans-→) = 0.15 ± 0.05, was obtained. The overall photoisomerization quantum yield of 11-cis with direct excitation at 254 nm was determined as Φ(iso)(d)(11-cis→) = 0.42 ± 0.05 assuming all-trans and 13-cis to be the primary products. Quenching rate constants of several of the sensitizer triplet states by retinal were measured by laser flash photolysis. Possible mechanisms that could account for the experimental results are discussed, and it is concluded that the photoisomerizations most likely involve the retinal triplet states as intermediates. Within this model the observed sensitizer triplet energy dependence of the primary product ratios suggests that the triplet states of the different retinal isomers are different mixtures of triplet excited species, and that the composition of these mixtures depends on the starting isomers as well as on the sensitizer triplet energy for energies below the vertical triplet energy of all-trans-retinal. In the light of a review of the existing literature on the direct and the sensitized photoisomerization of retinals these conclusions suggest substantial corrections to the accepted picture of retinal photochemistry.