15356-72-6Relevant articles and documents
Photocatalytic e → Z Isomerization of β-Ionyl Derivatives
Livingstone, Keith,Tenberge, Marius,Pape, Felix,Daniliuc, Constantin G.,Jamieson, Craig,Gilmour, Ryan
, p. 9677 - 9680 (2019/11/29)
An operationally simple E → Z isomerization of activated dienes, based on the β-ionyl motif intrinsic to retinal, is reported using inexpensive (-)-riboflavin (vitamin B2) under irradiation at 402 nm. Selective energy transfer from photoexcited (-)-riboflavin to the starting E-isomer enables geometrical isomerization. Since the analogous process with the Z-isomer is inefficient, microscopic reversibility is circumvented, thereby enabling a directional isomerization to generate the contra-thermodynamic product (up to 99% yield, up to 99:1 Z/E). Prudent choice of photocatalyst enables chemoselective isomerization to be achieved in both inter- and intramolecular systems. The principles established from this study, together with a molecular editing approach, have facilitated the development of a regioselective isomerization of a truncated triene based on the retinal scaffold.
β-Carotene autoxidation: Oxygen copolymerization, non-vitamin A products, and immunological activity
Burton, Graham W.,Daroszewski, Janusz,Nickerson, James G.,Johnston, James B.,Mogg, Trevor J.,Nikiforov, Grigory B.
supporting information, p. 305 - 316 (2014/05/06)
Carotenoids are reported to have immunological effects independent of vitamin A activity. Although antioxidant activity has been suggested as a basis of action, the ability of carotenoids to autoxidize to numerous non-vitamin A products with immunological activity is an alternative yet to be fully explored. We have undertaken a systematic study of β-carotene autoxidation and tested the product mixture for immunological activity. Autoxidation proceeds predominantly by oxygen copolymerization, leading to a defined, reproducible product corresponding to net uptake of almost 8 molar equivalents of oxygen. The product, termed OxC-beta, empirical formula C40H60O 15 versus C40H56 for β-carotene, contains more than 30% oxygen (w/w) and 85% β-carotene oxygen copolymers (w/w) as well as minor amounts of many C8-C18 norisoprenoid compounds. No vitamin A or higher molecular weight norisoprenoids are present. The predominance of polymeric products has not been reported previously. The polymer appears to be a less polymerized form of sporopollenin, a biopolymer found in exines of spores and pollen. Autoxidations of lycopene and canthaxanthin show a similar predominance of polymeric products. OxC-beta exhibits immunological activity in a PCR gene expression array, indicating that carotenoid oxidation produces non-vitamin A products with immunomodulatory potential.
OPSIN-BINDING LIGANDS, COMPOSITIONS AND METHODS OF USE
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, (2010/12/31)
Compounds and compositions of said compounds along with methods of use of compounds are disclosed for treating ophthalmic conditions related to mislocalization of opsin proteins, the misfolding of mutant opsin proteins and the production of toxic visual cycle products that accumulate in the eye. Compounds and compositions useful in the these methods, either alone or in combination with other therapeutic agents, are also described.
Synthesis, olfactory evaluation and determination of the absolute configuration of the β- and γ-Iralia isomers
Barakat, Assem,Brenna, Elisabetta,Fuganti, Claudio,Serra, Stefano
experimental part, p. 2316 - 2322 (2009/04/11)
The regioselective synthesis of the methyl-ionone isomers 6-9 is described. The enantiomers of the γ-isomers 8 and 9 are prepared by enzyme-mediated resolution of the corresponding 4-hydroxy derivatives followed by reductive elimination of the hydroxy group. The absolute configuration of the latter compound is determined by chemical correlation with the known α-isomers. Since all the isomers obtained are components of the artificial violet odourants sold under the trade name of Iralia, their odour properties are evaluated by professional perfumers.
Contribution of methyls in retinal side chain to regioselective photoisomerization of retinochromes
Tsujimoto, Kazuo,Sugiura, Jun'ichirou,Takemori, Nobuaki,Mizukami, Taku
, p. 1051 - 1052 (2007/10/03)
All-trans-9-demethyl-11-methylretinal was synthesized to elucidate the chromophoric interaction between hydrophobic part in retinochrome and 9-methyl substituent of retinal. Photoirradiation of its pigment efficiently gave the 11-cis-isomer in 90% regiose
A short and efficient regioselective approach to the C-6 to C-19 segment of bifurcaranes and a formal total synthesis of β-microbiotene, microbiotol and cyclocuparanol
Srikrishna,Anitha Nagamani
, p. 3393 - 3394 (2007/10/03)
Employing an epoxide rearrangement based ring contraction reaction, a short and efficient regioselective approach to the C-6 to C-19 segment of the toluquinol substituted diterpenes bifurcaranes, and its extension to a formal total synthesis of the sesquiterpenes (±)-β-microbiotene, (±)-microbiotol and (±)-cyclocuparanol are described. The Royal Society of Chemistry 1999.
Polyenylidene thiazolidine derivatives with retinoidal activities
Tashima, Toshihiko,Kagechika, Hiroyuki,Tsuji, Motonori,Fukasawa, Hiroshi,Kawachi, Emiko,Hashimoto, Yuichi,Shudo, Koichi
, p. 1805 - 1813 (2007/10/03)
Several polyenylidene thiazolidinedione or 2-thioxo-4-thiazolidinone derivatives were synthesized and their retinoidal activities were examined in terms of the differentiation-inducing ability towards human promyelocytic leukemia HL-60 cells and inhibitory effect on interleukin (IL)-1α-induced IL-6 production in MC3T3-E1 cells. Compounds containing a trimethylcyclohexenyl ring induced HL-60 cell differentiation with weaker activity than retinoic acid (1a) by one or two orders of magnitude. The thiazolidinedione derivatives (2, 5, 7) showed stronger activity than the corresponding 2-thioxo-4-thiazolidinone derivatives (3, 6, 8). The effects of a retinoid antagonist (LE540) and synergists (retinoid X receptor (RXR) agonists, HX600 or HX630) on the activities of thiazolidine derivatives indicate that these compounds elicit their activities through the nuclear retinoic acid receptors (RARs). All the thiazolidines examined also inhibited IL-1α-induced IL-6 production with IC50 values of 10nM order. The retinoidal activities of the thiazolidines are significant, considering that replacement of the carboxylic acid in retinoid structures with bioisosteric functional groups is generally ineffective, as seen in the structure-activity relationships of retinoidal benzoic acids.
NEW APPROACH TO THE CYCLIZATION OF TERPENOIDS
Kron, A. A.,Burdin, E. A.,Novikov, N. A.,Aul'chenko, I. S.
, p. 1901 - 1904 (2007/10/02)
The cyclization of pseudoionone, geranic acid, and its nitrile in the presence of catalytic amounts of acid at elevated temperature proceeds with high yield, while the corresponding cyclic products are formed predominantly as α-isomers.
Photochemische Reaktionen Zur Photochemie α,β-ungesaettigter γ,δ-Epoxyester I: Singulett- versus Triplettreaktivitaet
Alder, Alex Peter,Wolf, Hans Richard,Jeger, Oskar
, p. 1833 - 1855 (2007/10/02)
On triplet excitation (E)-2 isomerizes to (Z)-2 and reacts by cleavage of the C(γ),O-bond to isomeric δ-ketoester compounds (3 and 4) and 2,5-dihydrofuran compounds (5 and 19, s.Scheme 1). - On singulet excitation (E)-2 gives mainly isomers formed by clea
