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Accueil du site → Doctorat → États-Unis → 1973 → CHEMICAL CONSTITUENTS OF ARTEMISIA FILIFOLIA (TORR.)

University of Arizona (1973)


Torrance, Sterling Jay


Auteur : Torrance, Sterling Jay

Université de soutenance : University of Arizona

Grade : Doctor of Philosophy (PhD) 1973

The western sand sage Artemisia filifolia Torr. has been examined in order to determine the nature of its secondary metabolites. The steam volatile oil of A. fili folia was analyzed by fractional distillation and preparative GLC and was found to contain ten monoterpenes. Of these, four had been previously reported to be constituents of A. filifolia. This group consists of isophorone, 1,8-cineole, (-)-camphor, and (-)-filifolone. The remaining six mono terpenes of A. filifolia have not been reported as constitu ents of this plant. Four of the latter are of known structure and were found to be piperitenone, borneol, (-)-verbenone, and 3,5,5-trimethylcyclohex-2-en-l,4-dione. The last two unreported monoterpenes of A. filifolia are new compounds, shown by independent synthesis to be 1(S), 5(S) — (—)— 5— hydroxy-2,2,4-trimethylcyclohex-3-ene-l-carboxylic acid Y^lactone, and 1(R), 3(R)-(+)-3-hydroxy-2,2,4-trimethyl cyclohex’-4-ene’-l-carboxylic acid’ y-lactone. Some synthetic preparations toward the structure proof of these 2 lactones led to three other new monoterpenes. These are 2-hydroxy a,a,3-trimethylcyclopent-3-ene-l-acetic acid y-lactone, cis, v cis-3,4-dihydroxy-2,2,4-trimethylcyclohexane-l-carboxylic acid 5-lactone, and cis-4-hydroxy-trans-3-iodo-2,2,4-tri methylcyclohexane-l-carboxylic acid 6-lactone. Artemisia filifolia was also extracted with chloro form. The sodium hydroxide extract of the chloroform extract of the plant provided two acidic compounds. These were found to be the known flavone acacetin (5,7-dihydroxy 4 *-methoxy-flavone) and the new monoterpene-1(S)-(+)-5-keto 2,2,4-trimethylcyclohex-3-ene-l-carboxylic acid. The latter structure was proved by independent preparation. Column chromatography of the neutral chloroform extract of A. filifolia resulted in the isolation of one sesquiterpene lactone, shown to be the known colartin. Biosynthetic pathways are proposed for all compounds isolated from Artemisia filifolia.


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