Other Degraded Carotenoids

Other Degraded Carotenoids. A new synthesis of the fungal sex hormone ( )-(7 , 9 )-trisporic acid B methyl ester (114) utilized as the key step a Michael-aldol sequence on the /3-keto-ester (115) to yield the highly functionalized cyclo-hexenone (116). The latter underwent Wittig reaction with the phosphonium salt (117) to give (114). After basic alumina-catalysed hydrogen exchange in tritiated 

Kyushu Daigaku Nogakubu Gakugei Zasshi, 1976, 31, 49 (Chan. Abs., 1977, 87, 52 840). 

Syntheses have been reported for several other natural products related structurally to carotenoids, viz. dihydroactinidiolide (123) and tetrahydroactinidiolide (124), trans- and cis-a-damascone (125), dihydroedulans I and II, (51) and (52), bicyclodamascenones A and B, (53) and (54), the diastereoisomeric caparrapi oxides (126), ( )-a-chamigrene (127), and the novel passion-fruit ionone derivatives (47) and (48).  

Photochemical isomerization of trans- -ionol (128) in benzene gave the 1-cis-isomer in high yield. The photochemical behaviour of y,5- and S,e-unsaturated carbonyl compounds of the dihydroionone series has been studied in detail, and 

Lombardi, R. C. Cookson, H. P. Weber, W. Renold, A. Hauser, K. H. Schulte-Elte, B. Willhalm, W. Thommen, and G. Ohlofl, Helv. Chim. Acta, 1976, 59, 1158. 

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Other Degraded Carotenoids. The acetylenic diol (115), prepared by reaction of but-3-yn-2-ol dianion with 2,6,6-trimethyl-4,4-ethylenedioxycyclohex-2-en-l-one (116), afforded 3,5,5-trimethyl-4-(2-butenylidene)-cyclohex-2-en-l-one (117), a major constituent of Burley tobacco, on LiAlH4 reduction and hydrolysis.53... 

Other Degraded Carotenoids. The chemistry of abscisic acid (111) has been reviewed.In a stereoselective synthesis of (111), 2-c/5-3-methylpent-2-en-4-yl-l-ol (112) was used to introduce the 2-cis,4-trans geometry (abscisic acid... 

Other Degraded Carotenoids. Several syntheses of ionones and related compounds have been described. Some of these may prove useful for end-group construction in carotenoid synthesis. Thus 4-keto-j8-ionone (126) and 3,4-dehydro-jS-ionone (127) have been prepared by condensation of the sulphone (128) with propylene oxide, followed by elimination of phenylsulphinic acid and either oxidation or dehydration. A novel method utilizes a thermal acetylenic oxy-Cope rearrangement process to prepare the ionone compounds (129—131 R = Me) and analogues (R = Et or Pr ) from cyclohex-2-enylprop-2rynols (132). 

Other Degraded Carotenoids Carotenoid-Protein Complexes Physical Methods Separation and Assay N.M.R. Spectroscopy Electronic Absorption Spectroscopy Resonance Raman Spectroscopy X-Ray Structures Linear Dichroism... 

Tan, S. T., Wilkins, A. L., Holland, P. T., and McGhie, T. K. (1989). Extractives from New Zealand unifloral honeys. 2. Degraded carotenoids and other substances from heather honey. /. Agric. Food Chem. 37,1217-1221. 

The ahcycHc monoterpenic aldehyde safranal has a different biochemical origin, and is the main characteristic odorous component of saffron Crocus sativus, Iridaceae). Safranal is classified as a degraded carotenoid (apocarotenoid) as it is produced from zeaxanthin via hydrolysis of the bitter intermediate picrocrocin. Degradation of carotenoids produces a number of other aromatic compounds (see Section 9.9.5.2). A list of the names of major terpenoid aldehydes is shown in Table 8.11. 

The characteristic flavour component of raspberries Rubus idaeus ssp vulgatus, Rosaceae) 4-(4-hydroxyphenyl)butan-2-one is known as raspberry ketone (8-53). In addition to this compound, other important compounds include in particular methyl cinnamate, non-l-en-3-one, (Z)-hex-3-en-l-ol with a green flavour and degraded carotenoids, such as a-ionone, P-ionone and a-irone. 

A series of apocarotenoids (degraded carotenoids) was isolated from the species Aplysia kurodai whose origin was also the diet (Yamashita and Matsimo, 1990), and it appears that no other carotenoid has yet been isolated from any other species of the order Anaspidea. 

Abscisin II may be viewed as a monocyclic analog of these two anomalous sesquiterpenes. Alternatively, it may be one of a larger group of miscellaneous compounds which do not necessarily possess exactly 10 or 15 carbon atoms but may be looked upon formally (and perhaps actually) as degradation products of the carotenoids. This view is favored by the fact that the carotenoids are the only class of plant products in which cyclization of the type found in abscisin II is very common. Other examples of these compounds in-... 

Traditionally, dried or powdered plant material is used and extracts can be obtained by mixing the material with food-grade solvents like dichloromethane or acetone followed by washing, concentration, and solvent removal. The result is an oily product that may contain variable amounts of pheophytins and other chlorophyll degradation compounds usually accompanied by lipid-soluble substances like carotenoids (mainly lutein), carotenes, fats, waxes, and phospholipids, depending on the raw material and extraction techniques employed. This product is usually marketed as pheophytin after standardization with vegetable oils. 

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