Francine Libot

Electrospray ionization mass spectrometry in supramolecular chemistry : Characterization of non-covalent cyclodextrin complexes

A series of supramolecular complexes of various cyclodextrins (CDs) was studied. Among the 13 CD complexes synthesized, 11 could be characterizied by electrospray ionization mass spectrometry. Different supramolecular entities, with host : guest ratios of 1 :1 and 2 :1, were observed.

Pentacyclic triterpenoid and saponins from Gambeya boukokoensis.

Chemical studies of the EtOAc extract of Gambeya boukokoensis Aubr. et Pellegr. stem bark led to the isolation of eight compounds. Three of them were elucidated as new compounds and designated as: gamboukokoensein A, 1alpha,2alpha,3beta,19alpha,23-pentahydroxyurs-12-en-28-oic acid; gamboukokoenside A, 2beta,3beta,6beta,28-tetrahydroxyolean-12-en-23-oic acid 23-O-alpha-L-arabinopyranosyl ester and gamboukokoenside B, 6beta,28-dihydroxy-3-oxoolean-12-en-23-oic acid 23-O-alpha-L-arabinopyranosyl ester. The other five compounds were known and identified as myrianthic acid, protobassic acid, oleanolic acid, erythrodiol and chondrillasterol. Their structures were elucidated on the basis of one and two dimensional NMR spectroscopic techniques, FABMS, ESMS and chemical evidence.

A phenylpropanoid glycoside from Ballota nigra

A new phenylpropanoid glycoside, ballotetroside, has been isolated from the aerial parts of Ballota nigra. On the basis of chemical and spectral data, its structure has been established as (3,4-dihydroxyphenyl)-2-ethyl[alpha-L-arabinopyranosyl-(1-->2)-alp ha- L-rhamnopyranosyl-(1-->3)]-beta-D-apiofuranosyl-(1-->6)-4-O- caffeoyl-beta-D-glucopyranoside.

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.

Diterpene esters of malonic acid from the resin Ladano of Cistus creticus

Abstract Four labdane diterpenes, esterified with malonic acid were isolated from the resin ‘Ladano’ of the plant Cistus creticus subsp. creticus . Two of them, i.e. (13 E )-labd-7, 13-diene-15-yl malonic acid and di-[(13 E )-labd-13-ene, 8α-ol-15-yl] malonate, were new compounds. Their structures were determined by spectroscopic methods and confirmed by chemical correlations.