Biomedical subjects

G Pèpe

Publications and source records attributed to G Pèpe.

7 recordsLinked to original sources

PubMed2001

A new tetratertiary phosphine ligand and its use in Pd-catalyzed allylic substitution.

A new tetraphosphine, the cis-cis-cis-1,2,3,4-tetrakis(diphenylphosphinomethyl)cyclopentane (Tedicyp) 1 has been synthesized, characterized, and used in Pd-catalyzed allylic substitutions. The Tedicyp was easily prepared in seven steps from the commercially available himic anhydride. The structure of the complex Tedicyp-borane was determined by X-ray analysis. The tetraphosphine in combination with [Pd(eta(3)-C(3)H(5))Cl](2) affords a very efficient catalyst for allylic substitution of several allylic acetates. Under mild conditions, very high turnover numbers and turnover frequencies have been obtained.

Journal Article↗

PubMed2000

Tricarbonyl[(6a,7,8,9,10a-eta)-3,3-dimethyl-3H-benzo[f]chromene]chromium.

The title compound, [Cr(C(15)H(14)O)(CO)(3)], is a chromene complexed with tricarbonylchromium and it exhibits photochromic properties. The molecular geometry is compared to that of two similar complexes. The analysis results indicate that complexation has minor effects on the chromene structure.

Journal Article↗

PubMed1997

A new spiro[indoline-naphthoxazinic] spin trapping agent.

The synthesis and characterisation of a new spin trapping agent of the spiro[indoline-naphthoxazinic] family is reported. The EPR results of spin trapping experiments are also described, which indicate the ability of this nitrone to react with carbon-, oxygen- and sulphur-centered radicals.

Electron Spin Resonance Spectroscopy↗

PubMed1993

Force field calculations on five membered ring aminoxyl radicals.

Two force fields (MM2 and Genmol) have been applied to the modeling of five membered ring aminoxyl radicals. For the six molecules which were investigated the geometry of the conformation with the lowest strain energy was in very good agreement with the X-ray geometry. However owing to the high flexibility of five membered rings other conformations were shown to have a strain energy close to the energy minimum.

Cyclic N-Oxides↗

PubMed1991

Conformational analysis of the amino termini (5 residues) of human glycophorin AM and AN: differentiation of the structural features of the TN and T antigenic determinants in relation to their specificity.

The N-terminus of glycophorin A, the main transmembrane erythrocyte glycoprotein responsible for the MN blood-group specificity, has been modelled. As the minimum size of the protein recognised by the antiglycophorin A antibodies is the N-terminal glycopentapeptide, attention was focused on the TN and T antigenic determinants of this size in order to determine wether differences in 3D structure exist and how a specific response with different antibodies is induced.

Amino Acid Sequence↗

PubMed1990

MolStruc: a force field calculation program allowing interactive modifications of the force field parameters.

To analyze the influence of parameters and functions on the energy and geometry obtained through different force field calculations, we have developed program MolStruc. This software allows the user to choose between two sets of functions and parameters, MM2 and AMBER. The MM2 option of the program was developed to compute the coulombic energy in a dipole or monopole approximation. To establish comparisons between the energy values, the coulombic contribution is computed in the same way in the Amber and MM2 options of the program. The force field parameters can be handled interactively (through addition or modification). The program was used to study molecules of a representative sample displaying most of the problems encountered in molecular mechanics (MM).

Algorithms↗

PubMed1989

The computer program MolPot: a useful tool in chemical reactivity analysis.

MolPot is a fast program for producing reactivity diagrams of molecular compounds, particularly for drugs. These diagrams are characteristic of the molecule envelope and the Molecular Electrostatic Potential (MEP) of the molecule surface (van der Waals surface or the portion of this surface that is solvent accessible). The input data includes only the atom names and their Cartesian coordinates.

Computer Graphics↗