James A. Armstrong

Coumarins and their taxonomic value in the genus Phebalium

Abstract An examination of the aerial parts of 15 taxa (14 species, two subspecies) of Phebalium (Rutaceae) has confirmed the ubiquitous occurrence of coumarins in the genus. In total 34 coumarins were isolated, of which 28 are new to the genus and seven appear to be novel natural products. The latter have been identified as 7-[( E )-7-hydroxy-3,7-dimethylocta-2,5-dienyloxy]-coumarin, 5-methoxymarmesin, 2′3′-dehydromarmesin, 1′2′-epoxycasegravol-4′-isovalerate {7-methoxy-8-[1,2-epoxy-3-hydroxy-3-methyl-4-(isovaleroyl)-butyl]-coumarin}, murrangatin-′-acetate [7-methoxy-8-(1-acetoxy-2-hydroxy-3-methylbut-3-enyl)-coumarin], 3′,4′-dehydromurranganon acetate [7-methoxy-8-(1-acetoxy-2-oxo-3-methylbut-3-enyl)-coumarin], and 3′,4′-dehydroisomurranganon acetate [7-methoxy-8-(2-acetoxy-1-oxo-3-methylbut-3-enyl)-coumarin]. Earlier comments on the chemotaxonomic value of coumarins of Phebalium are updated in the light of these results.

Novel O-prenylated flavonoids from two varieties of Boronia coerulescens

Abstract The aerial parts of Boronia coerulescens ssp. spicata Rutaceae yielded nine flavonoids which were identified on the basis of detailed spectrosc

Alkaloids, flavonols and coumarins from Drummondita hassellii and C. calida

Abstract The aerial parts of both Drummondita hassellii and D. calida have yielded a number of simple furoquinoline alkaloids and polymethoxylated flavonols. Of the latter 3,5,6,7,8,4′-hexamethoxyflavonol (auranetin-5-methyl ether) and 3,5,7,8,4′-pentamethoxyflavonol (flindulatin-5-methyl ether), both isolated from D. calida, appear to be novel. In addition both species produced dihydrocinnamic acid derivatives, including the previously unrecorded trans-avicennic acid [6-(3-methylbut-1-(E)-3-dienyl)-5, 7-dimethoxy-2,2-dimethylbenzopyran-8-propanoic acid]. Finally, three novel coumarins were isolated from D. hassellii and identified as 6,7-di(3,3-dimethylallyloxy)-5-methoxycoumarin, 6,7-di-(3,3-dimethylallyloxy)-5-hydroxycoumarin and 7-(3,3-dimethylallyloxy)-6-hydroxy-5-methoxycoumarin. No coumarins were detected in D. calida. The systematic value of these findings is briefly discussed.

Tetra− and pentacyclic 6-c-monoterpenyl-5,7-dioxycoumarins from Eriostemon brucei and e. Brucei subspecies cinereus

Abstract An investigation of the aerial parts of Eriostemon brucei ssp. brucei and E. brucei ssp. cinereus revealed the presence, in one or both, of the coumarins eriobrucinol and 5′β-hydroxyeriobrucinol and five further 6- C -monoterpenyl-5,7-dioxycoumarins which are reported as natural products for the first time. These were, from the type subspecies, trace amounts of the two eriobrucinol regioisomers, which had previously been synthesized, and from E. brucei ssp. cinereus 4′β-hydroxyeriobrucinol and two tetracyclic coumarins which have been assigned the trivial names pseudobruceol-I and pseudobruceol-II. In addition the type subspecies yielded 5,7-dihydroxy-2-( n -nonaeicosanyl) chromone, which is also novel. All compounds were identified by means of comprehensive analysis of NMR spectra.

Pyranocoumarins as chemotaxonomic markers in Eriostemon coccineus and Philotheca citrina

Abstract Examination of the aerial parts of Eriostemon coccineus and Philotheca citrina has shown both to contain the unusual pyranocoumarins avicennol, avicennin and cis -avicennol. Three minor coumarins isolated from P. citrina have been identified as avicennol methyl ether, cis -avicennol methyl ether and avicennol ethyl ether. Philotheca citrina also yielded another pyranocoumarin, dipetalolactone, and the common lignan sesamin. Eriostemon coccineus , in addition to coumarins, gave the furoquinoline alkaloids maculosidine and γ-fagarine and two dihydrocinnanic acid derivatives, eriostoic acid and a new compound with a substitution pattern comparable to cis -avicennin and which has been assigned the trivial name cis -avicennic acid. The co-occurrence of these rare pyranocoumarins supports the contention that Philotheca is closely allied to certain taxa currently placed in Eriostemon sect. Nigrostipulae.

Sesquiterpenyl coumarins and geranyl benzaldehyde derivatives from the aerial parts of Eriostemon myoporoides

Abstract Examination of the aerial parts of Eriostemon myoporoides has led to the isolation of fifteen compounds including eight novel coumarins: (-)2′β-(2ξ,3-epoxy-3-methyl-1-oxobutyl)-2′-deoxybruceol, (-)2′β-(3-methyl-1-oxobut-2-enyl)-2′-deoxybruceol, (-)2′-{( E )-3-hydroxy-3-methylbut-1-enyl}-2′-deoxybruceol, (-)2′β-{( E )-3-hydroperoxy-3-methylbut-1-enyl}-2′-deoxybruceol, (-)2′β-(3-methyl-1ξ,2ξ,3-trihydroxybutyl)-2′-deoxybruceol, (-)2′β-(2ξ-hydroperoxy-3-methylbut-3-enyl)-2′-deoxybruceol, (-)2′β-(2ξ-hydroxy-3-methyl-1-oxobutyl)-2′-deoxybruceol and 8-geranyl-5,7-dihydroxycoumarin; three novel geranyl substituted benzaldehydes: 3-(6ξ-hydroperoxy-3,7-dimethylocta-2,7-dienyl)-4-hydroxybenzaldehyde, ( E )-3-(7-hydroperoxy-3,7-dimethylocta-2,5-dienyl)-4-hydroxybenzaldehyde and ( Z )-3-(7-hydroperoxy-3,7-dimethylocta-2,5-dienyl)-4-hydroxybenzaldehyde; two known coumarins: scopoletin and scoparone; a dihydrocinnamic acid derivative eriostemoic acid and a simple dial: 4-hydroxy-1,3-benzenedicarboxaldehyde. The chemotaxonomic significance of the sesquiterpenyl coumarins in the genus Eriostemon is discussed.

Pyranocoumarins from Eriostemon apiculatus

Abstract An examination of the aerial parts of Eriostemon apiculatus has shown it to contain the uncommon pyranocoumarins avicennol, cis -avicennol, dipetalolactone, avicennin and cis -avicennin. The last of these appears to be novel. The simple coumarin umbelliferone and the dihydrocinnamic acid derivative eriostemoic acid were also isolated. The occurrence of these pyranocoumarins supports the placement of this taxon close to Eriostemon coccineus in Eriostemon sect. Nigrostipulae-A.

An alkaloid, coumarins and a triterpene from Boronia algida

Abstract Examination of the aerial parts of Boronia algida has led to the isolation of six coumarins, an alkaloid and a triterpene. The coumarins were identified as ( + )-marmesin, 7-demethylsuberosin, 5-deoxyprotobruceol-II hydroperoxide, a mixture of the diastereomers of 5-deoxyprotobruceol-III 3′ξ-hydroperoxide and 3′-hydroxyxanthyletin; the alkaloid as 1-methyl-2-pentadecyl-4(1H)-quinolone and the dammarane triterpene as (E)-25-hydroperoxy-3β-hydroxydammar-20,23-diene. The latter compound and 3′-hydroxyxanthyletin are novel natural products. The chemotaxonomic significance of these isolates in the genus Boronia is discussed.

Terpenoids, alkaloids and coumarins from Boronia inornata and Boronia gracilipes

Abstract Aerial parts and roots of Boronia inornata yielded the sesquiterpenes spathulenol and 1 (10),5-germacradien-4-ol, the triterpenes moronic acid, moronic aldehyde (novel), betulonic acid and lupeol, the alkaloids dictamnine, evolitrine, isodictamnine and hordenine, and 8-(3,7-dimethyl-2,6-octadienyl)-7-hydroxycoumarin. A second sample of B. inornata gave the protolimonoids niloticin and piscidinol-A in addition to all those compounds noted above. A sample B. gracilipes yielded spathulenol, rutin and the triterpenes betulonic acid, betulonic aldehyde, oleanonic acid,3-epioleanonic acid and oleanonic aldehyde. Results are now available for investigations of species belonging to all three of the sections of Boronia and the distribution of compounds is discussed.

Dihydrochalcones from the aerial parts of Boronia inconspicua

Abstract From the aerial parts of Boronia inconspicua two novel dihydrochalcones, 2′,4,4′,6′-tetrahydroxy-5-( E -3,7-dimethylocta-2,6-dienyl)-3-(3-methylbut-2-enyl)dihydrochalcone and 2′,4,4′,6′-tetrahydroxy-3,5-di(3-methylbut-2-enyl)dihydrochalcone have been isolated and identified.