18526-49-3Relevant academic research and scientific papers
C10 Dialdehyde, Synthetic Method Thereof, and Synthetic Method of Beta-Carotene Using the Same
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Page/Page column 8, (2008/12/04)
The novel intermediate compound which can be efficiently utilized in the synthesis of carotenoid compounds based on the sulfone chemistry, the preparation method of the same, and the practical synthetic process for preparing β-carotene by the use of the above novel compound are disclosed. The synthesis of β-carotene is characterized by the double elimination reactions of the C40 compound containing both the benzenesulfonyl group and the group X (either halogen or ether), which can be prepared by the coupling reaction of the novel C10 dialdehyde with two equivalents of the C15 allylic sulfone, followed by the functional group transformation of the resulting C40 diol either to the corresponding halide or to the ether, to produce the fully conjugated polyene chain.
Unique properties of the 11-cis and 11,11′-di-cis isomers of β-carotene as revealed by electronic absorption, resonance Raman and 1H and 13C NMR spectroscopy and by HPLC analysis of their thermal isomerization
Hu, Ying,Hashimoto, Hideki,Moine, Gerard,Hengartner, Urs,Koyama, Yasushi
, p. 2699 - 2710 (2007/10/03)
In comparison with the all-trans and other cis isomers of β-carotene, the 11-cis and 11,11′-di-cis isomers exhibited the following unique properties. (1) The wavelengths of the Bu+←Ag- (0-0) absorption of these
Kinetic Model for Studying the Isomerization of α- and β-Carotene during Heating and Illumination
Chen, B. H.,Chen, T. M.,Chien, J. T.
, p. 2391 - 2397 (2007/10/02)
The thermoisomerization and iodine-catalyzed photoisomerization of all-trans-α- and all-trans-β-carotene were kinetically studied using regression models. Carotene samples were heated at varied temperatures or exposed to a 20 W light for varied lengths of time. Isomerization and degradation reactions were monitored using HPLC with diode array detection. Four cis isomers of β-carotene and three cis isomers of α-carotene were separated and detected. The degradations of both carotenes under heating at 150 deg C or iodine/light treatment may fit the reversible first- order model. 9-cis and 13-cis were the major β-carotene isomers formed during heating, while 13,15-di-cis was favored during iodine-catalyzed photoisomerization. The formation of 9-cis and 13-cis form all-trans-α-carotene was dependent upon the extent of heat or iodine/light treatment, and the latter was formed in greater amount under either treatment. Keywords: α-Carotene; β-carotene; thermoisomerization; photoisomerization; kinetic study
Triplet-Sensitized and Thermal Isomerization of All-Trans, 7-Cis, 9-cis, 13-Cis, and 15-Cis Isomers of β-Carotene: Configurational dependence of the Quantum Yield of Isomerization via the T1 State
Kuki, Michitaka,Koyama, Yasushi,Nagae, Hiroyoshi
, p. 7171 - 7180 (2007/10/02)
The products of triplet-sensitized photoisomerization (excitation at 337 nm of the sensitizer, anthracene) and thermal isomerization of β-carotene in n-hexane, starting from the all-trans, 7-cis, 9-cis, 13-cis, and 15-cis isomers, were analyzed by HPLC.Direct photoisomerization (excitation at 488 and 337 nm) was also examined for comparison.Three different isomerization patterns were found in both triplet-sensitized and thermal isomerization: pattern A, cis to trans isomerization around each cis bond; pattern B, trans to cis isomerization in the central part of the conjugated chain; and pattern C, cis to another cis isomerization.In the T1 state, the pattern A isomerization was predominant even for the peripheral-cis (7-cis and 9-cis) isomers and its efficiency was extremly high for the central-cis (13-cis and 15-cis) isomers.In the S0 state, the pattern B isomerization, instead, was predominant for the peripheral-cis isomers, and the pattern A isomerization was predominant only for the central-cis isomers.The quantum yields of triplet-sensitized isomerization (decrease of the starting isomer per triplet species generated) were determined to be as follows: all-trans, 0.04; 7-cis, 0.12; 9-cis, 0.15; 13-cis, 0.87; and 15-cis, 0.98.In direct photoisomerization, the quantum yield of isomerization at 488-nnm (337 nm) excitation was 4 (3) orders of magnitude lower than the above values, the relative values among the isomers being similar to the above.Further, the overall isomerization patterns of direct photoexcitation were similar to those of triplet-sensitized isomerization, supporting the idea that isomerization takes place via the T1 state even in the case of direct photoexcitation.Carbon-carbon ? bond orders of model polyenes in the T1 and S0 states were calculated by using the Pariser-Parr-Pople CI theorie; bond lengths were optimized by using a bond order-bond length relationship.Isomerization characteristics in the T1 and S0 states observed were discussed based on the results of the calculations.
