Prenylflavonoids and prenyl/alkyl-phloroacetophenones: synthesis and antitumour biological evaluation.

Several prenylflavonoids have been synthesised and tested against human tumour cell lines. The prenyl unit has been geranyl or a labdane diterpene. These labdane-flavonoids have been synthesised for the first time. The antitumour activity increase with the prenylation at C-8 position. Twenty-three C and O-prenylated acylphloroglucinols have been synthesised as well. In this case the C-alkylation products have resulted, in general, more active.

Synthesis of novel antitumoural analogues of dysidiolide from ent-halimic acid.

Several sesterterpenolides analogues of dysidiolide have been synthesized and their in vitro antitumoural activity against human HeLa, A549, HT-29 and HL-60 carcinoma cells is presented. The proliferation inhibition data showed a significant antitumour activity of the compounds 1b, 2a, 2b, 3a, 3b, 4a, 4b, 5, inhibiting proliferation of distinct cancer cell types with an IC(50) in the low micromolar range.

Synthesis of three marine natural sesterterpenolides from methyl isoanticopalate. First enantioselective synthesis of luffolide.

[Reaction: see text]. The synthesis of three marine sponge metabolites, luffolide (4), 5, and 6, are described for the first time, establishing the absolute configuration of these compounds. The key intermediate, aldehyde 17, was obtained from methyl isoanticopalate, 11. The addition of 3-furyllithium to 17 and subsequent photochemical oxidation give the gamma-hydroxybutenolide 5 and its epimer at C-16. Sesterterpenolide 6 is obtained by dehydration of 5. From the key aldehyde 17, luffolide (4) was obtained in six steps.

Microbial hydroxylation of sclareol by Rhizopus stolonifer.

Incubation of sclareol with Rhizopus stolonifer affords in high yield a mixture of triols with 18-hydroxy-sclareol as the main component.

1-Hydroxymethyl-4-phenylsulfonybutadiene, a versatile building block for the synthesis of 2,3,4-trisusbtituted tetrahydrothiophenes.

A method to synthesize chiral 2,3,4-trisusbtituted tetrahydrothiophenes in both enantiomerically pure forms starting from 1-hydroxymethyl-4-phenylsulfonylbutadiene is described.

Chemistry of epoxysulfones: straightforward synthesis of versatile chiral building blocks.

[reaction: see text] Several chiral building blocks have been obtained easily in large quantities from an epoxysulfone (9) that could be obtained in both enantiomeric forms from accessible starting materials.

Synthesis of bioactive sesterterpenolides from ent-halimic acid. 15-epi-ent-Cladocoran A and B.

The bioactive sesterterpenoid gamma-hydroxybutenolides 15,18-bisepi-ent-Cladocoran A and B, 1 and 2, and 15-epi-ent-Cladocoran A and B, 57 and 55, were synthesized from ent-halimic acid. The synthesized sesterterpenolids 2, 55, 57, and 59 inhibited cellular proliferation (IC(50) congruent with 2 micro M) of a number of human leukaemic and solid tumor cell lines.

Stereocontrolled synthesis of cyclopropanol amino acids from allylic sulfones: conformationally restricted building blocks.

[reaction: see text] A new amino acid methyl ester with a cyclopropanol has been synthesized starting from the allyl sulfone 10. The starting material, 10, could be obtained in both enantiomeric forms. The stereoselectivity of the cyclopropane formation has been studied by molecular modeling.