Synthetic nitrogen carotenoids: optically active carotenoid amines (original) (raw)
Carotenoids: A novel biomolecules for potential device application
Indian Journal of Physics
The presence of various ad. ,.,b,d goo.. In...' tb, _Ioondue-t ion current of carotenoids. Among different carotenoids crocetin is the~s ensitive sensor for ethanol vapour. Thin film surface cell shows faster response and recovery. Very high photoconductive response is obtained for crocetinaldehyde and can be used for optical switching devices. Carotenoids are capable of forming charge-transfer complex with iodine. About seven order of current enhancement is observed for Iycopene-iodine CT complex. A Mg/lycopeneiodine CT complex/C solid state battery is developed. Battery parameters indicate its applicability for microgadget energizer.
Molecules, 2012
A listing of carotenoids with heteroatoms (X = F, Cl, Br, I, Si, N, S, Se, Fe) directly attached to the carotenoid carbon skeleton has been compiled. The 178 listed carotenoids with C,H,X atoms demonstrate that the classical division of carotenoids into hydrocarbon carotenoids (C,H) and xanthophylls (C,H,O) has become obsolete.
Synthetic sulfur carotenoids II: Optically active carotenoid thiols
Tetrahedron: Asymmetry, 1993
3R,S'R)-Zeaxanthin WBS reacted with thioacetic acid or with thiocyano acid in a Mitsunobu reaction to provide the corresponding thioacetates and thiocyanates with inverted configuration. Reduction or hydrolysis of these intermediates provided (3&3'S)-3'-mercaptog,fl-caroten-3-01 and (3S)-2',3'-didehydro-g$-carotene-3-thiol whose CD spectra are discussed.
Facile method for spectroscopic examination of radical ions of hydrophilic carotenoids
Physical Chemistry Chemical Physics, 2009
Hydrophilic carotenoids, unusual members of an intrinsically hydrophobic family, and their radical ions are important reactants. An all-optical method for generating singly charged radical ions of a hydrophilic carotenoid (Car) is described. It relies on photolyzing an aqueous mixture of Car and a photoionizable auxiliary solute (A), and making conditions conducive to the capture, by Car, of the hydrated electron (e À aq) or the positive hole in A + or both. When A is Trolox (TOH), only e À aq can be captured, since TOH + deprotonates too rapidly to be a hole donor; when A is Trolox methyl ether (TOMe), both Car À and Car + are formed, since TOMe + lives long enough to transfer its positive hole to Car; formation of Car À is prevented under aerobic conditions.
Carotenoids, 2017
Pigments can be divided into four categories: natural, nature-identical, synthetic, and inorganic colors. Artificial colorants are the most used in food and pharmaceutical industries because of their advantages related to color range, price, resistance to oxygen degradation, and solubility. However, many natural pigments present health-promoting activities that make them an interesting option for human use and consumption. Natural colorants are derived from sources such as plants, insects, and microorganisms. Carotenoids are natural pigments with important biological activities, such as antioxidant and pro-vitamin A activity, that can be either extracted from plants and algae or synthesized by various microorganisms, including bacteria, yeasts, filamentous fungi, and microalgae. Advantages of microbial production include the ability of microorganisms to use a wide variety of low cost substrates, the better control of cultivation, and the minimized production time. After fermentation, carotenoids are usually recovered by cell disruption, solvent extraction, and concentration. Subsequent purification steps are followed depending on the application. The most prominent industrial applications of carotenoids, considering their health benefits, are in the food, feed, and pharmaceutical industries.
The Photochemistry of Carotenoids: Some Photosynthetic and Photomedical Aspects
Annals of the New York Academy of Sciences, 1993
The occurrence of carotenoid polyenes in the human diet and the resulting healthrelated effects are a direct consequence of the fact that carotenoids are vital constituents of the photosynthetic apparatus of green plants and other organisms. Worldwide , immense quantities of these materials are biosynthesized each year, and they find their way into the food chains of animals and humans through a variety of pathways. Carotenoids were selected by the evolving photosynthetic apparatus because of their unique photophysical properties. Thus, consideration of these properties and the ways in which photosynthetic organisms make use of them can help us understand some of the health-related roles of carotenes. This article will briefly review the photosynthetic functions of carotenoids and show how they can be mimicked in properly designed synthetic molecular systems. Finally, an illustration of how the results of these model system studies may be used to design medically useful carotenoid-containing agents will be presented. Carotenoid Photophysics This discussion applies to the genre of carotenoid pigments having nine or more conjugated double bonds including oxy-and hydroxy-substituted compounds, although there are, of course, small differences between pigments. The most obvious property of carotenes is their intense orange color, which results from absorption of light in the 400-550-nm region. Carotenes typically have very high extinction coefficients (E,,,-lo5) in this region. This strongly electric dipole allowed transition is from the ground state (So) to the second excited singlet state, Sz , of the carotenoid. As one would expect for an upper excited singlet state, the Sz species has a very short lifetime (on the order of 100 fs).' Because of the short
The carotenoids as anti-oxidants — a review
Journal of Photochemistry and Photobiology B: Biology, 1997
Carotenoids are abundant in many fruit.,, and vegetables and they play diver~e roles in photobiology, photochemi~,try and medic;he. Thi~ review concerns the reactivity of carotenoidx with singlet oxygen and the interaction of carotenoids with a range of tree radical~. Mcchani~m.~ associated with the anti-and pro-oxidant behaviour of carotencids are discussed including carotenoid interactions v, ith other anti-oxidants. © 1997 Elsevier Science S.A.