8066-07-7

Upstream product

• 26927-07-1 9-cis-violaxanthin 
• 69350-47-6 (1R,3S,6S)-6-((1E,3Z)-5-Hydroxy-3-methyl-penta-1,3-dienyl)-1,5,5-trimethyl-7-oxa-bicyclo[4.1.0]heptan-3-ol 
• 10153-97-6 (15E,9'Z)-neoxanthin 
• 69297-03-6 (1'S,2'R,4'S,2Z,4E)-5-(1',2'-Epoxy-4'-hydroxy-2',6',6'-trimethylcyclohexyl)-3-methylpenta-2,4-diensaeure-methylester 
• 19041-17-9 methyl 4-bromo-3-methylbut-2-enoate 
• 51318-62-8 ethyl 4-bromo-3-methylcrotonate 
• 122346-85-4 (-)-(1S,2R)-1,2-Epoxy-4,4-(ethylendioxy)-2,6,6-trimethylcyclohexan-1-carbaldehyd 
• 122346-75-2 (+)-(1R,2R)-1,2-Epoxy-4,4-(ethylendioxy)-2,6,6-trimethylcyclohexan-1-methanol 
• 145065-03-8 C₁₉H₃₀O₆ 
• 122346-87-6 (1'S,2'R,2Z,4E)-5-<1',2'-Epoxy-4',4'-(ethylendioxy)-2',6',6'-trimethylcyclohexyl>-3-methylpenta-2,4-diensaeure-methylester 
• 136621-82-4 (2Z,4E)-4,4-Ethylenedioxy-1-(4-carbonyl-3-methyl-1,3-butadien-1-yl)-1,2-oxo-2,6,6-trimethylcyclohexane 
• 117940-44-0 4,4-Ethylenedioxy-1-(5,6-dihydro-2H-4-methyl-2-oxopyran-6-yl)-1,2-oxo-2,6,6-trimethylcyclohexane 
• 122346-88-7 (2Z,4E)-3-Methyl-5-((1S,6R)-2,2,6-trimethyl-4-oxo-7-oxa-bicyclo[4.1.0]hept-1-yl)-penta-2,4-dienoic acid methyl ester 
• 23069-07-0 4,4-(Ethylendioxy)-2,6,6-trimethyl-1-cyclohexen-1-methanol 

Downstream Products

• 142204-43-1 (9'Z)-15,15'-Didehydroneoxanthin 
• 142204-43-1 15,15'-Didehydroneoxanthin 

Relevant academic research and scientific papers

Stereocontrolled syntheses of carotenoid oxidative metabolites, (-)-loliolide, (-)-xanthoxin, and their stereoisomers

We achieved the stereocontrolled syntheses of (-)-loliolide, (-)-xanthoxin, and their stereoisomers from (+)- or (-)-3-alkoxy-6-hydroxymethyl-1,1,5-trimethylcyclohexene through the corresponding syn and anti-epoxides, respectively, which were obtained by utilizing the highly diastereoselective Sharpless asymmetric epoxidation or mCPBA oxidation.

(6R,9'Z)-Neoxanthin: Synthesis, physical properties, spectra, and calculations of its conformation in solution

The synthesis of pure and crystalline (9'Z)-neoxanthin (6) is described. MnO2 Oxidation of (9Z)-C15-alcohol 7 at room temperature produces a mixture 8/9 of (9Z)- and (9E)-aldehydes. Predominant formation of the required (9Z)-aldehyde 8 is achieved by performing the oxidation at -10°. Condensation of 8 with the mono-Li salt of the symmetrical C10-diphosphonate 10 gave the (9Z)-C25-monophosphonate 11. The Wittig-Horner condensation of 10 with the allenic C15-aldehyde 1b, under selected conditions allows the preparation of pure and crystalline (9'Z)-15,15'-didehydroneoxanthin (12) and, after subsequent semireduction, of crystalline (15Z,9'Z)-neoxanthin (13). Thermal isomerisation of a AcOEt solution of 13 at 95° yields preferentially (9'Z)-neoxanthin (6). Our crystalline sample shows the highest ε-values in the UV/VIS spectra ever recorded. The CD spectra display a pronounced similarity with those of corresponding violaxanthin isomers. In contrast to the (all-E)-isomer 5, (9'Z)-neoxanthin undergoes very little isomerisation when heated to its melting point. For comparison purposes, a crystalline probe of 6 is also isolated from lawn mowings. Extensive 1H- and 13C-NMR investigations at 600 MHz of a (D6)benzene solution using 2D-experiments such as COSY, TOCSY, ROESY, HMBC, and HMQC techniques permit the unambiguous assignment of all signals. Force-field calculations of a model system of 6 indicate the presence of several interconverting conformers of the violaxanthin end group, 66% of which possess a pseudoequatorial and 34% a pseudoaxial OH-C(3'). The torsion angle (ω1) around the C(6')-C(7') bond, known to be of prime importance for the shape of the CD spectra, varies with values of 87° for 55% and 263° for 45% of the molecules. Therefore, the molecules clearly display a preference for the 'syn'-position of the C(7') = C(8') bond and the epoxy group. Unexpectedly, the double bonds of C(7') = C(8') and C(9') = C(10') are not coplanar. The deviation amounts to ± 20°, both in the 'syn'- and the 'anti'-conformation.

Convenient Syntheses of Optically Active Abscisic Acid and Xanthoxin

The Reformatzky reaction of 3-(bromomethyl)crotonate with an optically active epoxycyclohexane aldehyde derivative (3), followed by dehydration, gave the chiral dienoic acid (6) stereospecifically.The product was derived to optically active abscisic acid (1) and xanthoxin (2) successfully.

Synthesis of (6R,all-E)-Neoxanthin and Related Allenic Carotenoids

We present the first synthesis of enantiomerically pure neoxanthin (1) by a Wittig-Horner condensation between the ylide from the novel diethyl 12'-apo-15,15'-didehydroviolaxanthin-12'-phosphonate (35) and the allenic C15-aldehyde 31 (Scheme 4) via the crystalline 15,15'-didehydroneoxanthin (36; 70percent yield).After partial hydrogenation of the triple bond of 36 and isomerisation of the (15Z)-intermediate 37, neoxanthin (1) was obtained in good yield.Similar syntheses gave (15Z,9'Z)-neoxanthin (45; Scheme 5) and (9Z)-15,15'-didehydroneoxanthin (47; Scheme 6).Comparison of the physical data of synthetic 1 with those of a freshly isolated sample of neoxanthin from the flowers of Trollius europaeus confirmed their identity.The unusually low melting point of 1 is caused by a very easy thermal isomerisation into a mixture of the neochromes 4 and 5 (Scheme 1).Such a thermal rearrangement is not observed with 15,15'-didehydroneoxanthin (36).To explain this, we assume a zwitterionic excited state of the allenic group that induces the rearrangement of the violaxanthin end group into the furanoid epoxide (Scheme 7).

CAROTENOID METABOLISM AND THE BIOSYNTHESIS OF ABSCISIC ACID

The conversion of all-trans-violaxanthin to 9'-cis-neoxanthin was shown to occur in fluridone-treated etiolated Lycopersicon and Phaseolus seedlings, following exposure to light.The results of deuterium oxide labelling experiments supported this precursor/product relationship, and provided further evidence for the origin of abscisic acid.Several apo-carotenoids, putative by-products of abscisic acid biosynthesis, were synthesised by chemical oxidation but were not detected in plant extracts.In vitro, lipoxygenase cleaved neoxanthin and violaxanthin down to small (/=C13) fragments.It may be that in vivo any apo-carotenoids formed by the specific cleavage of 9'-cis-neoxanthin, during abscisic acid biosynthesis, are rapidly metabolized by lipoxygenase or similar enzymes.