References of "Dive, Georges"
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See detailImidazolidinones structurally-related to penicillins: synthesis, molecular modeling and biological evalutation
Marchand-Brynaert, Jacqueline; Lamotte-Brasseur, Josette; Dive, Georges ULg

in Drug Metabolism and Drug Interactions (1994), 11(2), 85-109

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See detailDesign and modeling of new PAF antagonists - 1,4-bis-(3',4',5'-trimethoxybenzoyl)-2-substituted carbonyloxymethyl piperazines
Heymans, Françoise; Lamouri, Aazdine; Batt, Jean-Pierre et al

in Journal of Lipid Mediators and Cell Signalling (1994), 10(1-2), 153-154

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See detail2,7-dihydroapogeissoschizine from root bark of strychnos Gossweileri
Quetin-Leclercq, Joëlle; Dive, Georges ULg; Delaude, Clément et al

in Phytochemistry (1994), 35(2), 533-536

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See detail2,7-dihydroxyapogeissoschizine from root bark of Strychnos gossweileri
Quetin-Leclercq, Joëlle; Dive, Georges ULg; Delaude, Clément et al

in Phytochemistry (1994), 35(2), 533-536

In this paper, we describe the isolation and structural determination of 2,7-dihydroxyapogeissoschizine, a new alkaloid from the root bark of Strychnos gossweileri. Elucidation of its structure is based ... [more ▼]

In this paper, we describe the isolation and structural determination of 2,7-dihydroxyapogeissoschizine, a new alkaloid from the root bark of Strychnos gossweileri. Elucidation of its structure is based mainly on 1D and 2D NMR studies; its conformation was optimized by energy minimization. This type of skeleton is related to geissoschizine but with the notable diffrence that the 1 and 17 positions are joined giving an additional fused ring. Such a seven-membered ring has ,to our knowledge, only been observed in apogeissoschizine, obtained after chemical tratment of two alkaloids ( geissospermine and geissoschizine). 2,7-dihydroxyapogeissoschizine is therefore, the first natural product possessing this skeleton. According to a preliminary test, this new alkaloid shows low toxicity to B16 melanoma cells, but not for non-cancer 3T3 fibroblasts cultured in vitro.THese results have to be confirmed by further tests. [less ▲]

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See detailDetailed Study of a Molecule in a Molecule N-Acetyl-L-Tryptophanamide in a Active-Site Model of Alpha-Chymotrypsin
Dive, Georges ULg; Dehareng, Dominique ULg; Ghuysen, Jean-Marie ULg

in Journal of the American Chemical Society (1994), 116(6), 2548-2556

Six complexes between a model active site of alpha-chymotrypsin (261 atoms) and N-acetyl-L-tryptophanamide (33 atoms) were optimized at the semiempirical AM1 level. In one of these complexes, a water ... [more ▼]

Six complexes between a model active site of alpha-chymotrypsin (261 atoms) and N-acetyl-L-tryptophanamide (33 atoms) were optimized at the semiempirical AM1 level. In one of these complexes, a water molecule was included. A detailed study at the geometric and energetic levels is presented. The discussion deals with the nature of the interaction, the effect of the environment, the ligand deformation, the backbone relaxation, the water molecule freedom, and the comparison with the molecular mechanics results. [less ▲]

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See detailInteractions between Active-Site-Serine Beta-Lactamases and Compounds Bearing a Methoxy Side Chain on the Alpha-Face of the Beta-Lactam Ring: Kinetic and Molecular Modelling Studies
Matagne, André ULg; Lamotte-Brasseur, J.; Dive, Georges ULg et al

in Biochemical Journal (1993), 293((Pt 3)), 607-611

The interactions between three class A beta-lactamases and compounds bearing a methoxy side chain on the alpha-face of the beta-lactam ring (cefoxitin, moxalactam and temocillin) have been studied. When ... [more ▼]

The interactions between three class A beta-lactamases and compounds bearing a methoxy side chain on the alpha-face of the beta-lactam ring (cefoxitin, moxalactam and temocillin) have been studied. When compared with the situation prevailing with good substrates, both acylation and deacylation steps appeared to be severely impaired. Molecular modelling studies of the structures of the Henri-Michaelis complexes and of the acyl-enzymes indicate a major displacement of the crystallographically observed water molecule which connects the glutamate-166 and serine-70 side chains and underline the role of this water molecule in both reaction steps. [less ▲]

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See detailEnergy Analysis on Small to Medium-Sized H-Bonded Complexes
Dive, Georges ULg; Dehareng, Dominique ULg; Ghuysen, Jean-Marie ULg

in Theoretica Chimica Acta (1993), 85(6), 409-421

Dimers (water-methanol, guanine-cytosine) as well as trimers (methanol-water-imidazole, formamide-methylformate-formamide), are studied as H-bonded complexes of increasing complexity. All the investigated ... [more ▼]

Dimers (water-methanol, guanine-cytosine) as well as trimers (methanol-water-imidazole, formamide-methylformate-formamide), are studied as H-bonded complexes of increasing complexity. All the investigated conformations have been fully optimized. In particular, it is the first time that all the intra- and intermolecular parameters of the guanine-cytosine complex are left variable. In minimal basis sets, the planar conformation has been found to be a first-order critical point. The minimal basis set MINI-1 has been adapted to provide nearly planar amides. The stability of the complexes is accounted for by four energy components of the same order: the first-order term (electrostatic + exchange), the polarization, the charge transfer and the correlation terms. In the case of the studied trimers, the energy components, apart from the electrostatic one, have been found to be nearly additive. [less ▲]

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See detailAnalytical calculation of the electrostatic interaction energy within the CNDO framework
Dehareng, Dominique ULg; Dive, Georges ULg; Ghuysen, Jean-Marie ULg

in International Journal of Quantum Chemistry (1993), 46(6), 711-734

This work analyses the adequacy of an analytical electrostatic energy formulation within the CNDO framework to predict the stable conformations of large molecular complexes. Comparisons are made with ab ... [more ▼]

This work analyses the adequacy of an analytical electrostatic energy formulation within the CNDO framework to predict the stable conformations of large molecular complexes. Comparisons are made with ab initio results for small systems such as water-formamide, methanol-water-imidazole, or guanine-cytosine and with AM1 results for two large systems: a molecular tweezer + the 9-methyladenine complex and a model active site of the alpha-chymotrypsin and its ligand complex. This approach is efficient in providing reliable conformers for large molecular systems in a very fast way. [less ▲]

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See detailDesign and synthesis of D,D-peptidase inhibitors
Ghosez, Léon; Dive, Georges ULg; Dumas, Stéphane et al

in Antibiotics and antiviral compounds: chemical synthesis and modification (1993)

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See detailDesign and modeling of new platelet-activating-factor antagonists.1. Synthesis and biological activity of 1,4-bis(3',4',5'-trimethoxybenzoyl)-2-[[(substituted carbonyl and carbamoyl)oxy]methyl]piperazines
Lamouri, Aazdine; Heymans, Françoise; Tavet, Fabrice et al

in Journal of Medicinal Chemistry (1993), 36(8), 990-1000

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See detailNew gamma-lactam homologs of penems
Marchand-Brynaert, Jacqueline; Couplet, Blandine; Dive, Georges ULg et al

in Bioorganic & Medicinal Chemistry Letters (1993), 3(11), 2303-2308

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See detailA VARIABLE MECHANISM FOR THE NUCLEOPHILIC VINYLIC SUBSTITUTIONS IN A SERIES OF GEM-DIHALOGENATED ALKENES BY A BIDENTATE SULFUR NUCLEOPHILE - AN EXPERIMENTAL AND AM1 THEORETICAL-STUDY
Gimbert, Yves; Moradpour, Alec; Dive, Georges ULg et al

in Journal of Organic Chemistry (1993), 58(17), 4685-4690

The nucleophilic substitutions of a series of gem-dihalogenated alkenes 3,5,7,8, and 9 (RS)2C=CX2 (X = Cl, F) with 1,2-benzenedithiolate b have been studied. Depending on the structures of the R groups ... [more ▼]

The nucleophilic substitutions of a series of gem-dihalogenated alkenes 3,5,7,8, and 9 (RS)2C=CX2 (X = Cl, F) with 1,2-benzenedithiolate b have been studied. Depending on the structures of the R groups (alkyl, saturated and unsaturated cycloalkyls, aromatic ring), the course of the reactions and the structures of the yielded products are modified. In the frame of the addition-elimination-type mechanism for these nucleophilic substitutions, the energy contents of the anionic intermediates, resulting from the additions of the nucleophile b to the unsaturated centers, is calculated at the AM1 method level. For the compounds 5, 7, 8, and 9, the calculated energies nicely corroborate the experimental results. For 3, anionic intermediates are no longer found by calculation, and a synchronous single-step substitution is strongly suggested. [less ▲]

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See detailPolarization correction of the electrostatic potential for aromatic-compounds - Study of the nucleophilic-attack
Dive, Georges ULg; Dehareng, Dominique ULg

in International Journal of Quantum Chemistry (1993), 46(1), 127-136

The electrostatic potential (EP) and the polarization correction (PL) on the EP were calculated for four aromatic compounds: benzene, chlorobenzene, phenol, and benzoic amide, at the ab initio SCF level ... [more ▼]

The electrostatic potential (EP) and the polarization correction (PL) on the EP were calculated for four aromatic compounds: benzene, chlorobenzene, phenol, and benzoic amide, at the ab initio SCF level within two basis sets: 6-31G** and MINI-1. One calculation was performed using the polarized MINI-1** basis set. The quantity total interaction energy (TEH) defined as -EP + PL can be used as an indicator of the nucleophilic attack preferential position. By reference to 6-31G**, MINI-I provides very satisfactory results. Moreover, the MINI-1** results are very similar to the MINI-I ones. It appears that -EP does not provide a reliable tool to study the nucleophilic attack susceptibility, whereas TEH seems to be very well adapted for this kind of approach. [less ▲]

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See detailPolarization-corrected electrostatic potentials of aromatic compounds
Dehareng, Dominique ULg; Dive, Georges ULg; Ghuysen, Jean-Marie ULg

in Journal of the American Chemical Society (1993), 115(15), 6877-6882

The electrostatic potentials (EPS) corrected for polarization (TPS) of the aromatic compounds benzene, aniline, chlorobenzene, nitrobenzene, phenol, benzamide, and N-phenylacetamide have been calculated ... [more ▼]

The electrostatic potentials (EPS) corrected for polarization (TPS) of the aromatic compounds benzene, aniline, chlorobenzene, nitrobenzene, phenol, benzamide, and N-phenylacetamide have been calculated at the ab initio SCF level within three basis sets: 6-31G**, MINI-1, and STO-3G. For chlorobenzene in its MINI-1-optimized geometry, the calculation was also performed within MINI-1**. By reference to 6-31G**, the MINI-1-computed EP is much more satisfactory than the STO-3G-computed EP, whereas the MINI-I and STO-3G basis sets give very similar total potentials corrected for polarization (TPs). The MINI-1** basis set appears to be miscalibrated for computing EPs. It provides qualitative results that differ from those obtained with the 6-31G** basis set. The EP has a negative well above the middle of the benzene ring, while the TP exhibits a negative crown just above the benzene carbon atoms, where electrophilic attack takes place. The TP calculated for the interaction of nitrobenzene with a hydride ion instead of a proton allowed analyzation of the effects of polarization on the positive EP above the N-C bond. [less ▲]

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See detailStreptomyces Albus G Serine Beta-Lactamase. Probing of the Catalytic Mechanism Via Molecular Modelling of Mutant Enzymes
Lamotte-Brasseur, Josette; Jacob-Dubuisson, Françoise; Dive, Georges ULg et al

in Biochemical Journal (1992), 282(Pt 1), 189-195

In previous studies, several amino acids of the active site of class A , β-lactamases have been modified by site-directed mutagenesis. On the basis of the catalytic mechanism proposed for the Streptomyces ... [more ▼]

In previous studies, several amino acids of the active site of class A , β-lactamases have been modified by site-directed mutagenesis. On the basis of the catalytic mechanism proposed for the Streptomyces albus G , β-lactamase [Lamotte- Brasseur, Dive, Dideberg, Charlier, Frere & Ghuysen (1991) Biochem. J. 279, 213-221], the influence that these mutations exert on the hydrogen-bonding network of the active site has been analysed by molecular mechanics. The results satisfactorily explain the effects of the mutations on the kinetic parameters of the enzyme's activity towards a set of substrates. The present study also shows that, upon binding a properly structured ,β-lactam compound, the impaired cavity of a mutant enzyme can readopt a functional hydrogen-bonding-network configuration. [less ▲]

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See detailEnergy hypersurface local properties of the O2HF-1 rearrangement
Dive, Georges ULg; Dehareng, Dominique ULg; Culot, Patrick et al

in Chemical Physics Letters (1992), 195(2-3), 189-193

This work analyses a case where Murrell's proposal, stating that a second-order point must lie above a first-order one, is apparently violated. Study at the SCF-UMP2 level within the D95 + + basis set, of ... [more ▼]

This work analyses a case where Murrell's proposal, stating that a second-order point must lie above a first-order one, is apparently violated. Study at the SCF-UMP2 level within the D95 + + basis set, of one critical point of the O2HF- anion, previously proposed to be of order two by Lopez, shows the importance of the electronic correlation. The critical point associated with the (2)PI first-order ones. The present analysis reveals that this contradistinction can be explained by three unconsidered elements: the local symmetry, the electronic correlation and the internal variables description. [less ▲]

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See detailInfluence of the Counterpoise Correction on the Optimized Relativi Degrees of Freedom in the H-Bonded Complex Water-Formamide
Dehareng, Dominique ULg; Dive, Georges ULg; Ghuysen, Jean-Marie ULg

in Theoretica Chimica Acta (1992), 81(4-5), 281-290

The correction of the basis set superposition error by the counterpoise method has been investigated at the SCF level for the weak H-bonded water-formamide complex and the results have been compared with ... [more ▼]

The correction of the basis set superposition error by the counterpoise method has been investigated at the SCF level for the weak H-bonded water-formamide complex and the results have been compared with the uncorrected results at the SCF, post SCF and semi-empirical AM1 and MNDO levels. Our particular concern has been the determination of the three optimized relative degrees of freedom and the relative stability of three C(s) geometrical conformations. The conclusions are that the counterpoise correction weakly conditions the variation in the degrees of freedom and the relative stabilities of the three conformers. The correction is obviously inadequate to describe intramolecular deformation. [less ▲]

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See detailA quasi-Newton algorithm for first-odrer saddle-point location
Culot, Patrick; Dive, Georges ULg; Nguyen, Van Hen et al

in Theoretica Chimica Acta (1992), 82

A new algorithm for the location of a transition-state structure on an energy hypersurface is proposed. The method is compared to three other quasi-Newton step calculations available in literature ... [more ▼]

A new algorithm for the location of a transition-state structure on an energy hypersurface is proposed. The method is compared to three other quasi-Newton step calculations available in literature. Numerical results derived from several examples are compared to those obtained by the two algorithms implemented in the Gaussian package. [less ▲]

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See detailMolecular properties of cinchona alkaloids: a theoretical approach
Oleksyn, Barbara; Suszko-Purzycka, Alina; Dive, Georges ULg et al

in Journal of Pharmaceutical Sciences (1992), 81(2), 122-127

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See detailSynthèse, étude théorique et évaluation biologique de dérivés du 4-amino-4H-1,2,4-triazole analogues des antibiotiques b-lactamiques
Pirotte, Bernard ULg; Dive, Georges ULg; Delarge, Jacques et al

in European Journal of Medicinal Chemistry (1992), 27(3), 193-205

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