François Thomasson

ORGANOLITHIUM MEDIATED SYNTHESIS OF PRENYLCHALCONES AS POTENTIAL INHIBITORS OF CHEMORESISTANCE

A number of substituted chalcones have been prepared by a novel LiHMDS-mediated aldol condensation, the first method consistent with the use of alkali-labile protecting groups such as tert-butyldiphenylsilyl or tert-butyldimethylsilyl. Chalcone substitution by prenylation increases their binding affinity to P-glycoprotein responsible for cancer cells chemoresistance.

Flavonoid glycosides from Erica cinerea

Abstract The new glycoside, limocitrin 4′-glucoside has been characterized from fresh flowers of Erica cinerea , together with the known compounds apigenin, apigenin 7-glucoside, quercetin 3-glucoside and 3-galactoside, gossypetin 8-methyl ether 3-glucoside and 3-galactoside as well as limocitrin 3-glucoside. Structural elucidation was achieved mainly by 1 H and 13 C NMR spectroscopy.

Synthesis of 4-octyl-2H-1,4-benzo-thiazin-3-ones.

Synthesis, physical and analytical properties of 6-alkylacylamino-4-octyl-2H-1,4-benzo-thiazin-3-ones derivatives are described. These new compounds were prepared by acylation and/or alkylation of the amino group under phase transfer catalysis conditions. Acid hydrolysis of the alkylacylamino-2H-1,4-benzo-thiazin-3-ones afforded N-alkylamino-benzothiazin-3-ones. Some of these compounds were evaluated in vitro for possible bacteriostatic activity.

Synthesis and microbiological activity of some 4-butyl-2H-benzo[1,4]thiazin-3-one derivatives

The synthesis and physicochemical properties of 4-butyl-2H-benzo[1,4]thiazin-3-one derivatives are described. These new compounds were synthesised by alkylation in 4-N position and acylation and/or alkylation of 6-NH2 by phase transfer catalysis. Acid hydrolysis of 6-alkylacylamino group yielded 6-alkylamino-4-butyl-2H-benzo[1,4]thiazin-3-ones. The antimicrobial in vitro activity was determined on five compounds.

6-hydroxygalangin and C-prenylated kaempferol derivatives from Platanus acerifolia buds☆

Abstract 6-Hydroxygalangin and three further C-prenylated flavonoids have been identified from Platanus acerifolia buds. Structural elucidation of the acetylated derivatives was achieved mainly by 1H NMR. The three related C-prenyl flavonoids were identified as 6-C-(1,1-dimethyl-1-propen-3-yl)-kaempferol, 8-C-(1,1-dimethyl-2-propen-1-yl)-kaempferol and 3′-C-(1,1-dimethyl-1-propen-3-yl)-kaempferol.

Synthesis and antiretroviral evaluation of 3-alkyl 2-piperazinone nucleoside analogs

Abstract Glycosylation of 3-alkyl N 4 -(3-hydroxypropyl) 2-piperazinones by protected 1- O -acetyl ribofuranoses produces nucleoside analogs in which the base is separated from the sugar by a hydrocarbon spacer arm. The preliminary in vitro test results against retroviruses seem promising for compounds bearing a long alkyl chain.

Flavonol triglycosides from Blackstonia peroliata

Three new flavonol triglycosides quercetin, kaempferol and isorhamnetin 3-rhamnosyl(1----2)galactoside-7-glucosides have been isolated from leaves and stems of Blackstonia perfoliata. This species together with three other genera of the tribe Gentianeae, subtribe Chlorae: Centaurium, Coutoubea and Eustoma, is unusual in producing flavonol glycosides instead of C-glycosyl flavones, the more characteristic flavonoid constituents of the Gentianaceae.

5-Arylmethylene-2,4-imidazolidinediones and 5-arylmethylene-2-thioxo-4-imidazolidinones derivatives: stereochemistry elucidation by 1H and 13C NMR

Abstract Derivatives of 5-arylmethylene-2,4-imidazolidinediones and 5-arylmethylene-2-thioxo-4-imidazolidinones were synthesized as potential aldose reductase inhibitors (ARI). The Z/E configuration was elucidated by homonuclear NOE difference spectra and by proton-carbon coupling constant measurement from 13C coupled spectra using GATEDEC and SFDEC programs.

Determination of the stereochemistry of substituted 5-methylenehydantoins and thiohydantoins by 13C NMR and homonuclear noe experiments

Abstract Basically the aim of this work is to define the accurate configuration of the exocyclic double bond of substituted 5-methylenehydantoins and thiohydantoins which have been conceived as potential Aldose Reductase inhibitors. A previsional survey based upon the chemical shifts analysis from 1H and decoupled 13C NMR spectra discloses, for a part of the family of compounds, the assignment of the Zconfiguration for unsubstituted (2,3) and N-3 substituted (6,7,9) derivatives, and the E-configuration for the N-1 substituted (8,11) ones. The qualitative study with Homonuclear NOE (8,11) and the coupling constant measuring 3 JC4-C=C-H6 from coupled 13C NMR (1–11), lead to the assignment of the accurate configuration of the whole familys compounds in agreement with the previsional study.

Acrodontiolamide, a chlorinated fungal metabolite from Acrodontium salmoneum

Abstract Acrodontiolamide, a new fungal metabolite has been isolated from the cell-free culture medium of Acrodontium salmoneum. Its purification was achieved by centrifugal TLC on silica gel and the structural analysis was based on spectroscopic data relative to both the natural product and its diacetyl derivative. This secondary metabolite, identified with 3-(p-nitrophenyl)-3-hydroxy-4-dichloromethoxy-isobutanamide exhibited antifungal properties.