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Featured researches published by J. Rambaud.


Journal of The Chemical Society-perkin Transactions 1 | 1984

Isoxazolidines by cycloadditions of N,α-diphenyl nitrone in the benzo[b]thiophene S-oxide and SS-dioxide series

A. Bened; Robert Durand; D. Pioch; P. Geneste; C. Guimon; Geneviève Pfister Guillouzo; Jean-Paul Declercq; Gabriel Germain; Pierrette Briard; J. Rambaud; R. Roques

1,3-Dipolar cycloadditions of N,α-diphenyl nitrone have been investigated in the 2- or 3-substituted (methyl, phenyl, chloro, bromo, piperidino, acetyl) benzo[b]thiophene S-oxide and SS-dioxide series. The S-oxide and SS-dioxide derivatives show the same ability to form adducts. The 2,3-dihydrobenzo[b]-thieno[2,3-d]isoxazolidines are generally formed only as a single regioisomer, except in the case of 2-methyl dipolarophiles where both regioisomers are formed. The regioselectivity is discussed in terms of frontier orbital interactions on the basis of CNDO/S calculations and photoelectronic spectral ionization potentials. The nitrone, which has an elbow shape, could lead to the formation of diastereoisomers but in fact only the trans-isoxazolidines are formed. There is less stereoselectivity in the S-oxide series since we obtained only one adduct with the 3-methyl dipolarophiles but both syn- and anti-epimers with the 3-phenyl derivatives. The bromo derivatives do not lead to any adduct. X-Ray structures are presented for the two adducts corresponding to the addition of the nitrone to benzo[b]thiophene SS-dioxide and to the 2-methyl derivative.


Acta Crystallographica Section C-crystal Structure Communications | 1992

Structure of polymorph II of (1R,3S)-1,2,2-trimethyl-3-(4-methylthiobenzoyl)-cyclopentanecarboxylic acid

J. Rambaud; B. Pauvert; A. Bouassab; A. Terol; P. Chevallet; Jean-Paul Declercq

C17H22O3S, M(r) = 306.407, orthorhombic, P2(1)2(1)2, a = 13.327 (5), b = 19.277 (8), c = 6.361 (2) angstrom, V = 1634 (1) angstrom3, Z = 4, D(x) = 1.245 Mg m-3, lambda(Cu Kalpha) = 1.54178 angstrom, mu = 1.77 mm-1, F(000) = 656, T = 293 K, R = 0.043 for 2574 observed reflections. Two crystalline forms of the title compound have been obtained but only one (form II) has given suitable crystals for X-ray structure analysis. The five-membered ring has an envelope conformation with C(2) 0.60 (1) angstrom out of the plane defined by the other four atoms. The absolute configuration has been established and appears to be identical to that of camphoric acid used in the synthesis. Molecules form dimers around the twofold axis by means of hydrogen bonds between their carboxylic groups.


Acta Crystallographica Section C-crystal Structure Communications | 1992

Structure of 2,6-dicyclohexylnaphthalene

P. Moreau; J. Solofo; P. Geneste; A. Finiels; J. Rambaud; Jean-Paul Declercq

C22H28, M(r) = 292.4, monoclinic, C2/c, a = 25.691 (4), b = 5.663 (1), c = 13.279 (2) angstrom, beta = 113.83 (1)-degrees, V = 1767.3 (4) angstrom 3, Z = 4, D(x) = 1.06 Mg m-3, lambda(Mo K-alpha) = 0.71069 angstrom, mu = 0.63 mm-1, F(000) = 640, T = 293 K, R = 0.048 for 1137 observed reflections. The 2,6-dicyclohexylnaphthalene contains a crystallographic symmetry centre. The presence of two bulky substituents involves only slight deviation from flatness for the naphthalene ring. The cyclohexyl substituents adopt a chair conformation.


Acta Crystallographica Section C-crystal Structure Communications | 1995

Polymorph(ii) of Methyl 3-(4-ethoxy-alpha-hydroxyiminobenzyl)-1,2,2-trimethylcyclopentanecarboxylate

J. Nurit; J. Rambaud; B. Pauvert; A. Terol; P. Chevallet; O. Doumbia; Jean-Paul Declercq

The title compound, C19H27NO4, is an intermediate product in the synthesis of oxazepinic and piperidinic compounds. Two crystalline forms of the title compound have been obtained but only one [form (II)] gave suitable crystals for X-ray structure analysis. The five-membered ring has an envelope conformation with C(2) 0.60 (5) angstrom out of the plane defined by the other four atoms. It has been established that the oxime group has a syn conformation and the two enantiomers form a dimer around the centre of symmetry by means of hydrogen bonds between their oxime groups.


Acta Crystallographica Section C-crystal Structure Communications | 1992

Structure of Potassium Hydrogen Diethylmalonate Monohydrate

A. Dubourg; Jl. Delarbre; L. Maury; J. Rambaud; Jean-Paul Declercq

[K(C7H11O4)].H2O, M(r) = 216.27, tetragonal, P4(3), a = 9.251 (3), c = 13.123 (4) angstrom, V = 1123 (1) angstrom 3, Z = 4, D(x) = 1.29 Mg m-3, lambda(Mo K-alpha) = 0.71069 angstrom, mu = 0.45 mm-1, F(000) = 456, T = 293 K, R = 0.041 for 1121 observed reflections. The asymmetric unit contains one formula unit of potassium hydrogen diethylmalonate linked by a hydrogen bond to the water molecule. Each molecule is intramolecularly hydrogen bonded and the carboxylic and carboxylate groups lying in the same plane of symmetry are equivalent.


Journal of Molecular Biology | 1991

Ionic interactions with parvalbumins. Crystal structure determination of pike 4.10 parvalbumin in four different ionic environments.

Jean-Paul Declercq; Bernard Tinant; Joseph Parello; J. Rambaud


Journal of Molecular Biology | 1992

Crystal structure of the unique parvalbumin component from muscle of the leopard shark (Triakis semifasciata). The first X-ray study of an alpha-parvalbumin.

Françoise Roquet; Jean-Paul Declercq; Bernard Tinant; J. Rambaud; Joseph Parello


Journal of Organic Chemistry | 1981

Dipolar Cycloaddition On the Transient Thiophene Sulfone - Isoxazoline and Isoxazolidine Derivatives

A. Bened; Robert Durand; D. Pioch; P. Geneste; Jean Paul Declercq; Gabriel Germain; J. Rambaud; R. Roques


Journal of Organic Chemistry | 1982

Isoxazolines By Cyclo-additions of Mesitonitrile Oxide With Benzo[b]thiophene S-oxide and S,S-dioxide - Structural Studies, Theoretical Explanations, and Kinetics

A. Bened; Robert Durand; D. Pioch; P. Geneste; Jean-Paul Declercq; Gabriel Germain; J. Rambaud; R. Roques


Journal of Pharmaceutical Sciences | 1994

Infrared, Raman, and 13C NMR Spectra of Two Crystalline Forms of (1R,3S)-3-(p-Thioanisoyl)-1,2,2-trimethylcyclopentanecarboxylic Acid

A. Terol; G. Cassanas; J. Nurit; B. Pauvert; A. Bouassab; J. Rambaud; P. Chevallet

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Jean-Paul Declercq

Université catholique de Louvain

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Bernard Tinant

Catholic University of Leuven

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Joseph Parello

Centre national de la recherche scientifique

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P. Geneste

École Normale Supérieure

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B. Pauvert

University of Montpellier

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Jean-Paul Declercq

Université catholique de Louvain

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R. Roques

Paul Sabatier University

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Robert Durand

École Normale Supérieure

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Gabriel Germain

Université catholique de Louvain

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Françoise Roquet

Centre national de la recherche scientifique

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