Rosa M. Rabanal

The synthesis of (-)-anamarine

Abstract The enantiospecific total synthesis of (-)-anamarine, starting from D-glucose, has been carried out.

The synthesis of D-asperlin

The synthesis of the D-enantiomer of asperlin has been carried out. The stereochemistry of the epoxide ring has been assigned as 6R,7S for this D-enantiomer.

13C NMR substituent effects in tetracyclic diterpenoids

Abstract The 13 C NMR chemical shifts of ent -beyer-15-ene, and one hydroxy and four acetoxy derivatives are reported. The substituent effects of the acetoxy groups upon the saturated and olefinic carbon atoms are discussed. Conformational aspects of the molecules are considered in the light of these effects.

Diterpenoids from Salvia oxyodon and Salvia lavandulifolia

Abstract Three new diterpenoids have been detected in Salvia oxyodon and identified as 3β-hydroxy-dehydroabietic acid, 3β-acetoxy-abieta-8(14)-en-18-oic acid 9α,13α-endoperoxide and 3β-hydroxy-abieta-8(14)-en-18-oic acid 9α,13α-endoperoxide. Salvia lavandulifolia yielded two known compounds ursolic acid and galdosol.

Two terpenoids from salvia bicolor

Abstract Two new terpenoids, 20( S ),24( R )-epoxy-dammar-12,25-diol-3-one and 12-methoxy-11,7-dihydroxydehydroabietane, were isolated from the roots of Salvia bicolor .

Chrysoeriol 7-(2″-O-β-d-allopyranosyl)-β-d-glucopyranoside from Sideritis grandiflora

Abstract The aerial parts of Sideritis grandiflora yielded a new flavone glycoside, identified as chrysoeriol 7-(2″-allosylglucoside).

A dimer of d-pinocarvone from Cedronella canariensis

Abstract From the aerial parts of Cedronella canariensis a dimer of d -pinocarvone, cedronellone, has been isolated, together with large amounts of d -pinocarvone and ursolic acid. The structure of cedronellone was established by chemical and spectroscopic means.

Reactions of abietic acid methyl ester with m-chloroperbenzoic acid

Abstract Abietic acid methyl ester reacts regioselectively with m-chloro-perbenzoic acid, in the presence of water to yield a mixture of the two epimeric 13,14-monoepoxides. These epoxides further react affording a mixture of 1,2- and 1, 4-unsaturated diols, The overall yield of the reaction is acceptably good (70–80%). The formation of these and other products are discussed.

A synthetic approach to olguine: a model study

Abstract A model study for a synthetic approach to the α,β-unsaturated δ-lactone olguine is reported starting from 1,2:3,4-di- O -isopropylidene-α- d - galacto -hexodialdo-1,5-pyranose by Wittig reaction with (1,3-dioxolan-2-ylmethyl)triphenyl-phosphonium bromide and epoxidation of the resulting olefins. The crystal and molecular structures of the intermediate epoxide 6,7-anhydro-1,2:3,4-di- O -isopropylidene-α- l - erythro - d - galacto -octopyranose have been determined.

Regioselective reactions of abietic acid methyl ester

Abstract Ozonolysis of abietic acid methyl ester 1 in the presence of mercuric acetate afforded the 13,14-seco-derivative in fair yield (50%). Selenium dioxide oxidation of 1 in t -butanol gave 9-α-hydroxy-abietic acid methyl ester 6 , dehydroabietic acid methyl ester 4 and its 7α-hydroxy-derivative 4b .