Total Synthesis of C31-Methyl Ketone Apocarotenoids 2: The First Total Synthesis of (3R)-Triophaxanthin.

Stereoselective total synthesis of the acetylenic carotenoids alloxanthin and triophaxanthin

“…23 Its spectral data were in good accordance with those reported. 19 Although the circular dichroism (CD) spectrum of the prepared compound (Fig. 3) showed weak Cotton effects, it was similar to that of reported natural product.…”

“…Completely synthetic triophaxanthin (2: Scheme 2) has been obtained only once previously by Haugan, 19 who noted that using the C 15 -acetylenic aldehyde was selected for the synthesis of 2 to avoid the formation of the 9Z isomer. However, that synthesis was achieved over 13 linear steps from (−)-actinol (3) through a C 15 + C 10 + C 5 + C 1 = C 31 strategy, in which the stereoselectivity of the two Wittig condensations remained to be improved.…”

“…Its spectral data were in agreement with those reported. 19 [((1R,1′R)-(3E,5E,7E,9E,11E,13E,15E)-3,7,12,16-Tetramethyloctadeca-3,5,7,9,11,13,15-heptaen-1,17-diyne-1,18diyl)bis(3,5,5-trimethylcyclohex-3-ene-4,1-diyl)bisoxy]bis-(triethylsilane) (23) NaOMe (1 M in MeOH; 2.0 mL, 2.0 mmol) was added to a solution of the phosphonium salt 12 (960 mg, 1.72 mmol) and C 10dialdehyde 20 (65 mg, 0.40 mmol) in CH 2 Cl 2 (10 mL) at rt. After being stirred at rt for 1.5 h, the mixture was poured into saturated aq.…”

Synthesis, Characterization, Anti-Inflammatory and in Vitro Antimicrobial Activity of Some Novel Alkyl/Aryl Substituted Tertiary Alcohols

“…The chalcone derivatives were prepared in a single step by the Claisen-Schmidt condensation of 3-hydroxy-acetophenone with suitably substituted benzaldehydes; the synthesis and characterization data has been reported earlier [ 21 ]. The tertiary alcohols 1-10 were synthesized by the nucleophilic addition of freshly prepared Grignard reagents to the carbonyl carbon of the suitably substituted chalcones [ 22 ]. The physical constants of the synthesized tertiary alcohols 1-10 are presented in the Experimental section.…”

Absolute configurational assignment of 3-hydroxycarotenoids

“…The compounds used in the present studies (Fig. 1) ranged from polyene 3-hydroxycarotenoids such as zeaxanthin 8 18 to more complex structures containing allenes as in paracentrone 12, 19 triple bonds as in the apocarotenoid 9, 20 triophaxanthin 10, 21 apohopkinsiaxanthin 11 22 and tetradehydroastaxanthin 15, 23 ketones in 11, 22 astaxanthin 13, 24 tetrahydrozeaxanthin-8,8Ј-dione 14 25 and 15 and a Z-double bond in 11. In some cases the compounds had opposite chirality or two different chiral hydroxys as in astaxanthin 13 and lutein 16.…”