New substituted 1-(2,3-dihydrobenzo[1, 4]dioxin-2-ylmethyl)piperidin-4-yl derivatives with alpha(2)-adrenoceptor antagonist activity.

The emergence of a novel theory concerning the role of noradrenaline in the progression and the treatment of neurodegenerative diseases such as Parkinson's and Alzheimer's diseases has provided a new impetus toward the discovery of novel compounds acting at alpha(2)-adrenoceptors. A series of substituted 1-(2, 3-dihydrobenzo[1,4]dioxin-2-ylmethyl)piperidin-4-yl derivatives bearing an amide, urea, or imidazolidinone moiety was studied. Some members of this series of compounds proved to be potent alpha(2)-adrenoceptor antagonists with good selectivity versus alpha(1)-adrenergic and D(2)-dopamine receptors. Particular emphasis is given to compound 33g which displays potent alpha(2)-adrenoceptor binding affinity in vitro and central effects in vivo following oral administration.

Requirements for P-glycoprotein recognition based on structure-activity relationships in the podophyllotoxin series.

Podophyllotoxin and epipodophyllotoxin react with tubulin at the same binding site as colchicine, but in contrast to colchicine, do not appear to exert their cytotoxicities by mechanisms dependent on P-glycoprotein (Pgp) expression. To investigate structural requirements for Pgp recognition a series of podophyllotoxin and epipodophyllotoxin derivatives have been synthesized. Their interactions with the multidrug resistance-related protein Pgp have been studied by evaluating their relative cytotoxicities versus P388-sensitive murine leukemic cells and a classic multidrug-resistant (MDR) Pgp-overexpressing subline (P388/ADR), and their relative tubulin polymerization inhibitory activities against microtubular proteins have been determined. Based on tridimensional structure-activity relationships within this series of compounds, structural requirements for Pgp recognition have been identified. Moreover, proposals are made for extending these criteria to other chemical classes of anticancer drugs.

Differentiation between partial agonists and neutral 5-HT1B antagonists by chemical modulation of 3-[3-(N,N-dimethylamino)propyl]-4-hydroxy- N-[4-(pyridin-4-yl)phenyl]benzamide (GR-55562).

The synthesis and binding affinity at cloned h5-HT1D, h5-HT1D, and h5-HT1A receptors of 3-[3-(N,N-dimethylamino)propyl]-4-hydroxy- N-[4-(pyridin-4-yl)phenyl]benzamide (2, GR-55562) and four O-methylated analogs are described. The functional activity of these compounds was determined at the h5-HT1B receptor using a [35S]GTP gamma S binding assay. The four analogs have been prepared in order to evaluate the influence of the alkylamino side chain conformation on binding and intrinsic activity. Whereas 2 and its derivatives display a similar binding affinity profile, major differences arise from analysis of the intrinsic activity data at h5-HT1B receptors. The O-methylated analog of 2, 3-[3-(N,N-dimethylamino)propyl]-4-methoxy- N-[4-(pyridin-4-yl)phenyl]benzamide (3a), and the (1Z)-3-(N,N-dimethylamino)prop-1-enyl derivative (3c) act as neutral and potent antagonists (in a similar way to 2), while the 3-(N,N-dimethylamino)-prop-1-ynyl (3b) and (1E)-3-(N,N-dimethylamino)prop-1-enyl (3d) analogs display nonnegligible agonist activity. Molecular modeling studies show that, when the common triaryl portions of the molecules are overlapped, the partial agonists and the neutral antagonists differ by a near-orthogonal orientation of the NH+ projection to the hydrogen-bond receptor site.

[Structural analysis of vinorelbine in solution determined by nuclear magnetic resonance spectrometry]. / Analyse structurale de la vinorelbine en solution déterminée par spectrométrie de résonance magnétique nucléaire.

An active partnership between the National Centre for Scientific Research (CNRS) and the laboratories Pierre Fabre is underpinning the development of a new molecule, vinorelbine, whose tartrate received marketing authorization in France in 1989, under the name of Navelbine. This medicine was first recommended for the treatment of bronchial cancer "not small cell", then, in 1991, for the treatment of metastatic breast cancer. In 1994, its registration in United States was granted for the treatment of bronchial cancer "not small cell". Vinorelbine is obtained by hemisynthesis using two antecedent monomeric alkaloids, catharanthine and vindoline, followed by a modification of the catharanthine nucleus, so as to produce the first 5' nor vinca-alkaloid. The chemical structure of vinorelbine has been examined in our laboratory using nuclear magnetic resonance spectrometry. Bearing in mind their complexity, the total attribution of the proton spectrum and the carbon-13 spectrum has required experiments for homonuclear (1H-1H) and heteronuclear (1H-13C and 1H-15N) correlation. These experiments have been carried out using a BRUKER spectrometer operating at the nominal proton frequency of 200 MHz in direct detection mode, then with a 400 MHz spectrometer equipped with the reverse detection mode. The chemical structure has thus been analyzed with no ambiguity. The results of this structural study will be presented in due course. We have also undertaken a comparative conformational study between base vinorelbine in chloroform solution and ditartrate vinorelbine (Navelbine) in methanolic solution. The conformation of the vinorelbine molecule in solution in these different solvents have been studied with NOESY (Nuclear Overhauser Effect Spectroscopy) experiments. The results of these experiments have been confirmed by data stemming from molecular modelization.

Binding of arylpiperazines, (aryloxy)propanolamines, and tetrahydropyridylindoles to the 5-HT1A receptor: contribution of the molecular lipophilicity potential to three-dimensional quantitative structure-affinity relationship models.

A set of 280 5-HT1A receptor ligands were selected from available literature data according to predefined criteria and subjected to three-dimensional quantitative structure-affinity relationship analysis using comparative molecular field analysis. No model was obtained for serotonin analogues (19 compounds) and aminotetralins (60 compounds), despite a variety of alignment hypotheses being tried. In contrast, the steric, electrostatic, and lipophilicity fields alone and in combination yielded informative models for arylpiperazines (101 training compounds and 12 test compounds), (aryloxy)propanolamines (30 training compounds and four test compounds), and tetrahydropyridylindoles (54 training compounds) taken separately (models A, B, and C). Arylpiperazines and (aryloxy)propanolamines were then combined successfully to yield reasonably good models for 131 compounds (model D). In a last step, the three chemical classes (185 compounds) were combined, again successfully (model E). This stepwise procedure not only ascertains self-consistency in alignments but it also allows statistical signals (i.e., favorable or unfavorable regions around molecules) to emerge which cannot exist in a single chemical class. The models so obtained reveal a number of interaction sites between ligands and the 5-HT1A receptor, and extend the information gathered from a model based on homology modeling.

An improved synthesis of 18-norandrost-4-ene-3,17-dione.

We describe the synthesis of 13 beta- and 13 alpha-H-18-nor-androst-4-ene-3,17-dione (1a and 1b) from 18-hydroxyprogesterone (18-->20) hemiketal, via the 18-acetoxy-17 beta-hydroxyandrost-4-en-3-one formed by a modified Baeyer-Villiger reaction. Saponification of 18-acetoxyandrost-4-ene-3,17-dione with sonication, then retroaldolization in the presence of a formaldehyde trap, methone, afforded the mixture of 1a and 1b with 80% yield in a "one-pot" procedure and at room temperature. This yield was greatly improved, compared with the already published procedure.