The synthesis of (−)-kessane, starting from natural (+)-aromadendrene-II

Antimalarial (+)-trans-Hexahydrodibenzopyran Derivatives from Machaerium multiflorum

“…Mixture A was further separated by another CPTLC (2 mm silica gel rotors), using n-hexane-CH2-Cl2 (9:1) as eluant, to give (-)-kessane as a pale yellow oil (36 mg; [R]D -1.7°; lit. 11 [R]D -6.1°], followed by a mixture of 1 and 2 (300 mg). A portion of the mixture (50 mg) was separated by semipreparative RP-HPLC (column: ODS prodigy 10µ, 250 × 10 mm; detector: UV-254 nm), using 95% MeCN-H2O as solvent, which afforded 1 [16 mg; Rf 0.73, silica gel, solvent: n-hexane-CH2Cl2 (8:2)], followed by 2 (16 mg; Rf 0.70).…”

“…The spectral data of (-)-kessane were in agreement with those reported in the literature. 11 Machaeriol A (6aR,7,8,9 ,10,10a -Hexahydro-6,6,9-trimethyl-3-phenylethylene-6H-dibenzo[b,d]pyran-1-ol) ( Antimalarial/Parasite LDH Assay. The in vitro antimalarial assay procedure 12 utilized at the NCNPR, University of Mississippi, is an adaptation of the parasite lactate dehydrogenase (pLDH) assay developed by Makler et al, 23,24 using a 96-well microplate assay protocol with two P. falciparum clones [Sierra Leone D6 (chloroquine-sensitive) and Indochina W2 (chloroquine-resistant)].…”

“…Centrifugal preparative TLC, followed by reversed-phase HPLC (see Experimental Section) of the n-hexane fraction, resulted in the isolation of two HHDBPs (1 and 2), as well as (-)-kessane, 11 a sesquiterpene oxide previously isolated from Valeriana officinalis. 13 The molecular formula C 24 H 28 O 2 for 1 was established by positive-ion ESI-HRMS.…”

Crystal and molecular structure of (+)-[1aR-(1a?,3a?,7?,7a?,7b?)]-decahydro-3a-hydroxy-1,1,7-trimethyl-1H-cyclopropa-[a]naphthalen-4-one, C14H22O2

“…(+)-Aromadendrene (2) is a sesquiterpene, which occurs in large quantities in the oil of Eucalyptus globulus and is a potential raw material for the synthesis of other sesquiterpenes (Gijsen et al, 1990(Gijsen et al, , 1991(Gijsen et al, , 1992. The ~-hydroxy ketone (1) can be synthesized from (-)apoaromadendrone (3) in three steps in almost quantitative yield and might be used in the synthesis of related sesquiterpenes with a maaliane, aristolane or eudesmane skeleton (Gijsen et al, 1993).…”

ELECTROPHILE MEDIATED HETEROATOM CYCLIZATIONS ONTO C-C Π-Bonds. PART 2: METAL ION MEDIATED CYCLIZATION

“…Treatment of the diol 255 with mercuric acetate followed by reduction afforded the tricycle 256 which was readily converted in high yield to the natural product 257. 83 …”