564-88-5Relevant articles and documents
Selective isomerization of retinal upon two-photon excitation
Sashima, Tokutake,Hashimoto, Hideki,Koshihara, Shin-ya
, p. 380 - 385 (2007/10/03)
The products of photo-isomerization when excited directly up to the two-photon-allowed 1Ag- excited state of alltrans and five cis isomers of retinal were determined. The composition of the isomers at the photo-stationary state was drastically changed as compared to one-photon excitation. The production of the 13-cis isomer was selectively increased, and the production of the dicis isomers was observed in the case of a direct excitation upon the 31Ag- state, although they were hard to be produced by one-photon excitation in n-hexane solution. These results clearly evidenced that there exist isomerization pathways via two-photon-allowed excited 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
Retinal, derivatives and their therapeutic use
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, (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.
Thermal Sigmatropic Rearrangements of Vinylallenes Leading to 11-cis-Retinoids and the Novel Properties of 9-cis,11-cis,13-cis-Retinal and 11-cis,13-cis-Retinal
Knudsen, Christopher G.,Chandraratna, Roshantha A. S.,Walkeapaeae, Leslie P.,Chauhan, Yeshpal S.,Carey, Stephen C.,et al.
, p. 1626 - 1631 (2007/10/02)
The thermally induced sigmatropic hydrogen shift of vinylallene 5 provided a route to highly hindered 11-cis-retinoids.The coupling ot the hetero cuprate 14 with the propargyl benzoate 13b gave the vinylallene 5, which upon heating (69 deg C, 2 h) gave three geometrically isomeric retinoids: 11-sis (8), 11-cis,13-cis (9), and 9-cis,11-cis,13-cis (11).The fourth possible geometric isomer, 9-cis,11-cis (10), was unstable to the conditions of thermolysis and underwent further electrocyclizations to the tricyclic compound 22.The thermal rearramgement of 9,10-allene 5, though highly specific for the formation of 11-cis-retinoids, exhibits no selectivity in the formation of Δ9 and Δ13 double bonds.The highly hindered 11-cis,13-cis- and 9-cis,11-cis,13-cis-retinals, 9b and 11b, exhibit extraordinary electronic absorption spectra in that they exhibit their main maxima (302 nm) actually to the blue of the corresponding alcohols.The retinals 9b and 11b were thermally unstable and underwent clean isomerization to 13-cis-retinal and 9-cis,13-cis-retinal, respectively.
Transient Phenomena in the Pulse Radiolysis of Retinyl Polyenes. 1. Radical Anions
Raghavan, N.V.,Das, P.K.,Bobrowski, K.
, p. 4569 - 4573 (2007/10/02)
The spectra and kinetics of formation and decay of radical anions of a number of retinyl polyenes have been studied in methanol and 2-propanol at room temperature, using pulse radiolysis and kinetic spectrophotometry.The bimolecular rate constants for the attachment of solvated electrons, e-MeOH, to the retinyl polyenes are in the diffusion-controlled limit (8.6 x 109-1.6 x 1010 M-1 s-1).The radical anions of retinol and retinol acetate have their spectral maxima at 370-390 nm, and undergo decay very slowly with second-order kinetics.On the other hand, the radical anions of retinal, retinal n-butylamine Schiff base, and retinoic acid/ester have spectral maxima at 430-510 nm, and decay by first-order kinetics in methanol with rate constants in the range 1 x 104-1 x 106 s-1.The decay rates of radical anions of retinal and retinoic acid/ester become considerably longer on going from methanol to less acidic alcohol, 2-propanol, suggesting that protonation by solvent is the major mode of their decay in protic media.In the case of retinal Schiff base, an additional slow process with bimolecular rate constant 9.0 x 107 M-1 s-1 im methanol is observed for the formation of radical anion and is ascribed to the electron-transfer reaction from the methanol radical, .CH2OH.
