Pr Jefferies

Poly-3-hydroxyalkanoates from marine and freshwater cyanobacteria

Abstract Polyesters of ( R )-3-hydroxybutanoic and ( R )-3-hydroxypentanoic acids have been isolated from Aphanothece species, a freshwater cyanobacteri

Labdane diterpenes from an acacia species

Abstract Two new diterpenes, (13 E )-labd-13-ene-3β,8α,15-triol and (13 E )-3β,8α-dihydroxylabd-13-en-15-oic acid have been isolated from an unclassified Acacia sp. Chemical and spectroscopic evidence for their structure is presented. The known labdanes, sclareol, 13- epi -sclareol and (13 E )-labd-13-ene-8α,15-diol were also isolated.

Metabolites of the green algae, Caulerpa species

Abstract Five Caulerpa species available in Western Australia have been investigated for the presence of terpenoid metabolites. A new bicyclic diterpene, containing a labd-7-ene skeleton and a 1,4-diacetoxybutadiene moiety, has been isolated from C. trifaria. C. brownii, C. flexilis, C. peltata and C. racemosa lacked significant quantities of terpenes and only caulerpin could be isolated from C. peltata and C. racemosa .

The chemistry of the euphorbiaceae—XI: The diterpenes of ricinocarpus muricatus and the stereochemistry of eperuic acid☆☆☆

Abstract The isolation of three new diterpenes from Ricinocarpus muricatus Muell. Arg. is described. Their structures have been established as eperuane-8β,15-diol (Ia), eperuane-8β,15,18-triol (VIa) and 15,16-dihydroxyeperu-8(20)-en-18-oic acid (VIIIa). Eperuic acid(III) has been shown to be antipodal to labd-8(20)-en-15-oic acid at all points except C-13.

The chemistry of Dodonaea SPP—IV : Diterpene and flavonoid components of D. attenuata☆

Abstract Further details are given for the assignment of absolute stereochemistry to the acetoxyhydroxy-acid (1) from D. attenuata and the lactone (6) from the var. linearis. The latter also provided a diene-acid shown to have structure 28. Reductive cyclisation of the tosylate of the latter gives a cyclopropane derivative (31). A flavone from the var. linearis is shown to be 5,7-dihydroxy-3,4′,6-trimethoxyflavone (32).

Serrulatane diterpenes from Eremophila spp.

Abstract Nine new serrulatane diterpenes have been isolated from various Eremophila species. Chemical and spectroscopic evidence for their structure is presented.

Isoprenoid dihydroquinones from a brown alga, Cystophora sp.

Abstract The lipids-soluble extract of the brown alga Cystophora sp. has yielded three new derivatives of geranyltoluquinol.

Structure and stereochemistry of bertyadionol

Abstract The structure of bertyadionol, a member of a new class of diterpenes, has been elucidated by chemical and physical methods. The absolute configuration of the cyclopropane ring was determined by degradation of bertyadionol to (−)- cis -homocaronic acid dimethyl ester. Application of Nuclear Magnetic Double Resonance techniques, INDOR and NOE measurements, allowed the determination of the absolute stereochemistry of two of its derivatives.

The chemistry of the euphorbiaceae—XIII : Flavones and minor diterpenes from ricinocarpus muricatus☆

Abstract The new diterpene acids, eperu-8(20)-en-15,18-dioic acid (IIIa), 15-hydroxyeperu-8(20)-ene-18-oic acid (IIId) and the Δαβ-butenolide (Va) have been isolated from Ricinocarpus muricatus, which has also yielded the new flavone pigments 5,3′,4′-trihydroxy-3,7,8-trimethoxyflavone (IXc) and 5,7,3′,4′-tetrahydroxy-3,8-dimethoxyflavone (IXd).

The chemistry of the Western Australian rutaceae—VI : Two novel coumarins from Eriostemon brucei☆

Abstract Eriobrucinol (1) has been related to hydroxyeriobrucinol (4) by oxidation of the methyl ether of the latter to a ketone (8) and desulphurisation of the derived thioketal. The structures of the coumarins are derived from chemical and spectroscopic arguments. Assignment of the all cis configuration for the alicyclic system is supported by evidence for conformational inversion in the 1′ hydroxy derivative (11).