Aurora Bellino

New diterpenes from Sideritis sicula

Abstract Two new diterpenes have been isolated from Sideritis sicula : sideripol, ent -18-acetoxy-7α-hydroxykaur-15-ene and epoxysideritriol, ent -15β,16β-epoxykauran-7α,17,18-triol. The previously known diterpene eubol, ent -7α-acetoxykaur-16-en-15β,18 diol has also been obtained from the same source.

Eubotriol and eubol, new diterpenes fromSideritis euboea

2 new diterpenes Eubotriol (ent-kaur-16-ene-7α, 15β, 18triol) (I), and eubol (ent-kaur-16-ene-7α-acetoxy-15β, 18 diol) (II) have been isolated from Sideritis euboea Helder.

Coumarins from Seseli bocconi

Abstract A new khellactone, bocconin, in addition to known compounds, have been isolated from Seseli bocconi subsp. bocconi and subsp. praecox Gamisans . Their structures were elucidated on the basis of spectral analyses and hydrolytic studies.

Siderone, a diterpene from Sideritis syriaca

Abstract Siderone, a new keto-diterpene, has been isolated from the petrol extract of the inflorescence of Sideritis syriaca . Its structure and stereochemis

Ucriol, an epoxy-diterpene from Sideritis syriaca

Abstract The isolation of a new epoxy-diterpene from the inflorescence of Sideritis syriaca (S. sicula Ucria) is described. Its structure and stereochemistry were established by spectroscopy and partial synthesis.

A diterpene, distanol, from Sideritis distans

Abstract A new diterpene, distanol, has been isolated from the petrol extract of the aerial part of Sideritis distans Wild. Its structure stereochemistry has been assigned by spectroscopic methods.

Carbon-13 Nuclear Magnetic Resonance Spectra of 2-Arylidene-3(2H)-benzofuranones

Etude de la structure des arylidene-2(2H) benzofuranones-3 substitues a partir des spectres RMN de 13 C, et discussion sur les effets substituants

Partial synthesis of ent-kaur-16-ene-15β,18-diol and ent-kaur-16-ene-7α,15β,18-triol

Treatment of ent-15β,16β-epoxykauran-18-ol (V) with boron trifluoride–ether complex in dimethyl sulphoxide or direct photo-oxygenation of ent-kaur-15-en-18-ol (IV) gave the expected ent-kaur-16-ene-15β,18-diol (I). This product is suggested to be identical with natural candidiol. Treatment of ent-15β,16β-epoxykaurane-7α,18-diol (VIII)(natural sideroxol) with boron trifluoride–ether complex in dimethyl sulphoxide or photo-oxygenation of ent-kaur-15-ene-7α,18-diol (II)(natural sideridiol) gave ent-kaur-16-ene-7α,15β,18-triol (VII).

Further reactions of sideridiol [(–)-kaur-15-ene-7β,19-diol]

The secondary hydroxy-group of sideridiol [(–)-kaur-15-ene-7β,19-diol](I) has been confirmed as being in the 7- rather than the 12-position. Bromination of methyl (–)-7-oxokauran-19-oate (IXb) gives methyl (–)-6β-bromo-7-oxokauran-19-oate (Xb); treatment of the latter with base gives (–)-7-oxokaur-5-en-19,6-olide (XII) mainly. Better yields of lactone (XII) are obtained by heating a solution of bromo-ester (Xb) in dimethyl sulphoxide under reflux. The n.m.r., o.r.d., and c.d. data for the bromo-ester (Xb) are discussed.