Z. Tanee Fomum

Prenylated isoflavonoids from Erythrina sensegalensis

Abstract Two novel prenylated isoflavonoids, 3,5,4′-trihydroxy-8-(γ,γ-dimethylallyl)-2″, 2″-dimethylpyrano [5″,6″:6,7]coumaronochromone and 5,2′,4′-trihydroxy-8-(γ,γ-dimethylallyl)furano [4″,5″:6,7] isoflavone, have been isolated from the stem bark of the Cameroonian medicinal plant, Erythrina senegalensis , in addition to five known pentacyclic triterpenes, β-amyrin, maniladiol, erythrodiol, oleanolic acid and cornulacic acid. Their structures were determined by spectroscopic methods.

Prenylated isoflavanone from Erythrina eriotricha

Bioassay-directed fractionation of a methylene chloride extract of the root bark of Erythrina eriotricha resulted in the isolation of a novel isoflavanone, named eriotrichin B, and the five known pterocarpans, isonorautenol, erybraedin A, erybraedin C, erybraedin D and erybraedin E. The structure of the new compound has been investigated by extensive spectroscopic studies, including 2D NMR and chemical evidence. The in vitro antimicrobial spectrum and potencies of the isolated compounds are also reported.

Erythrinasinate, an ester from three Erythrina species

Abstract The novel ester n -octacosanyl-3-hydroxy-4-methoxy cinnamate has been isolated from the stem bark of Erythrina senegalensis , E. glauca and E. mildbaedii and its structure determined by spectroscopic data and degradative studies. The known pterocarpan erythrabyssin-1 has also been isolated from . glauca .

Isoflavones and alkaloids from the stem bark and seeds of erythrina senegalensis

Abstract Two new isoflavones, erysenegalensein L, 5,6′,4′-trihydroxy-8-(2‴-hydroxy-3‴-methylbut-3‴-enyl)-2″,2″-dimethylpyrano [5″,6″,6,7] isoflavone and erysenegalensein M, 5,4′-dihydroxy-8-(2‴-hydroxy-3‴-methylbut-3‴-enyl)-2″, 2″-dimethylpyrano [5″, 6″: 6, 7] isoflavone have been isolated from the stem bark of the Cameroonian medicinal plant Erythrina senegalensis . The seeds of this plant afforded erysodine, glucoerysodine and hypaphorine. Their structures were determined by the usual spectroscopic methods, 2D NMR techniques and were confirmed by chemical reactions.

Phenolic constituents from Drypetes armoracia

The methanol extract of the dried stem bark of Drypetes armoracia Pax & Hoffm. afforded two compounds named drypearmoracein A, (E)-4,5,6,7-tetrahydroxy-2-benzylhept-2-enoic acid and drypearmoracein B, 2,3-dihydroxy-9,10-tetrahydroanthra-1,4-quinone along with five known compounds: friedelan-3 beta-ol, friedelin, friedelane-3,7-dione, drypemolundein B and beta-stigmasterol. Their structures were established on the basis of spectroscopic analysis and chemical evidence.

Millettonine, a guanidine alkaloid from Millettia laurentii

Abstract Millettonine, a guanidine alkaloid with a new skeleton, has been isolated from the stem bark of Millettia laurentii and its structure determined from a spectrometric study including mass spectrometry and NMR.

Further flavonoids from Erythrina species

Abstract A new dihydroflavonol, eriotrinol, and a new prenylated flavanone, sigmoidin G, have been isolated from the stem bark of Erythrina eriotricha and E. sigmoidea, respectively. Their structures were established as (2R,3R)-5,4′-dihydroxy-3′-methoxy-6″,6″-dimethylpyrano [2″,3″ : 7,6] dihydroflavonol and 5,7,5′,4″,5″-pentahydroxy-6″,6″-di-methylpyrano [2″,3″4:3′,4′] flavanone on the basis of spectroscopic means and chemical evidence. The previous known 4′-O- methylalpinumisoflavone, sigmoidin B and pentacyclic triterpene, erythrodiol, have been also isolated.

Conrauinones C and D, two isoflavones from stem bark of Millettia conraui☆

Abstract Analysis of the stem bark of Millettia conraui led to the isolation of two new O -geranylated isoflavones named conrauinones C and D together with the known 7-hydroxy-6-methoxy-3′,4′-methylenedioxyisoflavone. The structure elucidation of the two new compounds by spectroscopic studies is described.

Allenes-41 : The addition of thiols to allenyl- and phenylpropynyl- nitrile and the formation of thiazolines and benzothiazoles

Abstract Thiols add to allenylnitriles to give unconjugated nitriles which may be isomerised to conjugated enesulphide nitriles either at high temperature (200°) or with base. Phenylpropynenitrile gives conjugated adducts directly. Heating the conjugated adducts from aminoethanethiols at > 200° results in 5-exotrig ring closure and elimination of acetonitrile to give thiazolines and benzothiazoles.

Triterpenoid saponins from Erythrina sigmoidea

Abstract Two new triterpenoid saponins, designated sigmoside C and D, have been isolated from the methanol extract of the stem bark of Erythrina sigmoidea in addition to the known soyasapogenol-B and 3-O-[β- d -glucopyranosyl]-sitosterol . The structures of the saponins were determined by chemical and spectroscopic means as 22-O-[β- d -glucopyranosyl]-soyasapogenol-B and 22-O-[α- l -rhamnopyranosyl]-soyasapogenol-B , respectively.