J.G. Urones

Triterpenes from Euphorbia broteri

The triterpenes have been investigated in the aerial part and the latex of Euphorbia broteri. The aerial part contains two new triterpenes, 25,26,27-trisnor-3β-hydroxy-24-dimethoxycycloartane and 3,4-seco-4(23),14-taraxeradien-3-oic acid, and eleven other triterpenes identified as cycloartenol, butyrospermol, 24-methylenecycloartanol, cycloart-25-ene-3β,24-diol, euphan-8,25-diene-3β,24-diol, 3β-hydroxycycloart-25-ene-24-one, obtusifoliol, 3,4-seco-4(23),20(30)-lupadien-3-oic acid (canaric acid), betulin, cycloart-23-ene-3β,25-diol and the C-24 diastereomers of cycloartane-3β,24,25-triol. The latex contains a new triterpene, 24,25-epoxycycloartanol (C-24 diastereomers), and nine other compounds identified as euphol acetate, cycloartenyl acetate, butyrospermyl acetate, 24-methylenecycloartanyl acetate, euphol, cycloartenol, butyrospermol, 24-methylenecycloartanol and obtusifoliol.

Diterpenoids from Nepeta tuberosa subsp. reticulata

Abstract Three new diterpene compounds have been isolated from Nepeta tuberosa subsp. reticulata and their structures elucidated by spectroscopic methods. They were identified as diisopimaryl malonate isopimarylmalonic acid and 7-oxo-isopimara-8,15-dien-18-ol. We have also isolated 4aα,7α,7aβ-nepetalactone, 4aα,7α,7aα-nepetalactone, 3α-hydroxy-4α,4aα,7α 4α,4aα,7α,7aα-dihydronepetalactone, isopimaryl acetate, isopimarol, isopimaric acid, 8(14),15-isopimaradien-7α,18-diol, myrceocomunic acid and α-tocopheryl quinone.

Pyrrolizidine alkaloids from Senecio gallicus and S. Adonidifolius

Abstract Four alkaloids, ligularizine, senkirkine and senecionine N-oxide, were isolated from S. gallicus. Apart from florosenine, a new alkaloid was isolated from S. adonidifolius and identified as 12,13,19-trihydroxy-15,20-epoxy-15,20-dihydro(12S,15R,20R senecionan-11,16-dione. Two dimensional spectroscopic correlation experiments (1H1H and 13C1H) were performed, permitting the unequivocal assignation of the 1H and 13C NMR spectra of the alkaloids and enabling us to correct some of the data appearing in the literature.

Meroterpenes from Cystoseira usneoides II

Abstract Two new meroterpenes, usneoidols Z and E, have been isolated from the brown seaweed Cystoseira usneoides . Their structures were established by means of 2D NMR experiments: 1 H/ 1 H (COSY) and 1 H/ 13 C one bond and long range (HCCORR) correlations. Both compounds exhibit antitumoural and antiviral activities.

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.

Meroterpenes fromCystoseira usneoides

Abstract Two new meroterpenes have been isolated from the brown seaweed Cystoseira usneoides usneoidone E and usneoidone Z. Their structures were established mainly by means of 2D NMR experiments: 1 H/ 1 H (COSY) and 1 H/ 13 C one bond and long range (HCCORR) correlations. Both compounds exhibit antitumoural and antiviral activities.

Ent-isolariciresinol in Reseda suffruticosa

Abstract A new lignan, ent-isolariciresinol, has been isolated from the ethanolic extract of the aerial parts of Reseda suffruticosa together with sitosterol glucoside.

Functionalization at C-12 in labdanic diterpenes: synthesis of the natural diterpenic lactones isolated from Cistus ladaniferus L.

Abstract Oxidative cyclization of Labdanediol (XII) and methyl Labdanolate (Ib) with Pb(OAc)4, and subsequent oxidation with reagents as RuO4, O3, CrO3, or (But)2 CrO4 affords, in excellent yield, the natural diterpenic lactones II, III, VII, VIII, XI and XIII, isolated from Cistus ladaniferus L.

Labdane diterpenoids from Cistus ladaniferus

Abstract Three new diterpenic acids have been isolated from Cistus ladaniferus : 6,8(17) labdadien-15-oic, 7-oxo-8-labden-15-oic and 6β-acetoxy-7-oxo-8-labden-15-oic acids, beside labdanolic, 6-oxocativic,7α-hydroxy-8(17)-labden-15-oic, 8α-methoxy-labda-15-oic and 8α-hydroxy-13( E )-labden-15-oic acids.

Terpenoids from Nepeta tuberosa subsp.reticulata (II)

Abstract Four new diterpenoid compounds have been isolated from Nepeta tuberosa subsp. reticulata and their structures elucidated by spectroscopic methods and chemical correlations as abietatrien-3β-ol, isopimara-8,15-dien-7β,18-diol, isopimara-8,15-dien-7α,18-diol and 7α-hydroxy-isopimara-8(14), 15-dien-18-yl malonate. We have also isolated the known terpenoids acetyl isocupressic acid, isopimara-8(14),15-dien-7α,18-diol, phytol, ursolic acid, and the steroids sitosterol and sitosterol glucoside.