Christian Courseille

Chimie organometallique: XXX. Etude par resonance magnetique nucleaire du proton et par radiocristallographie du N-methylindolechrome-tricarbonyle

Abstract The structure of N -methylindolechromium tricarbonyl ( 4 ) in the solid state has been determined by X-ray crystallography. The projection of the chromium atom on the N -methylindole plane does not coincide with the center of symmetry of the benzene ring; the tripod is distorted and the overall conformation of the complex is gauche rather than eclipsed. Study of the 1 H NMR spectrum of complex 4 in solution at +20°C and −38°C leads to similar conclusions. The results explain the nucleophilic attack at carbon atoms 4 and 7 of complex 4 .

Conversion of adenosine to a pentacyclic structure by a 4-nitroquinoline-1-oxide metabolite model

Abstract A new pentacyclic compound 2A has been obtained from the reaction of adenosine 1 with 1-acetoxy-4-(acetoxyimino)-1,4-dihydroquinoline 3 , a model for the ultimate metabolite of the carcinogen 4-nitroquinoline-1-oxide. 9-propyladenine 5 gives an analogous pentacyclic product 6A whose crystal structure has been determined.

Structure de la di(thyminyl-1)-1,8 dioxa-3,6 octane

C I6H22N406, triclinic, space group P i , a = 12.356(1), b = 9.341 (2), c = 8.524 (2)/k, a = 1 1 6 . 0 8 ( 2 ) , f l = 9 6 . 1 0 ( 1 ) , y = 9 2 . 5 8 ( 1 ) °, V = 8 7 4 / k 3, D c = 1.39 Mg m -a, Z = 2. Final R = 0.041 for 2704 observed reflections. The triethylenedioxy chain does not appreciably disturb the stacking capacity of the

A simple conversion of tryptophan to a yohimbane derivative

DL-Tryptophan in 0,1 N HCl reacts with ninnydrin (triketoindane hydrate) at room temperature to give a brown precipitate; washing the precipitate with cold methanol leaves a yellow compound which is crystallized from boiling methanol (C20H14O4N2, 1 CH3OH). X-ray diffractometry showed that the crystals belong to the monoclinic system, with P21/n as a spatial symmetry group; the unit cell (a = 12.016 A; b = 13.336 A; c = 12.128 A; s = 113.45°) contains four molecules, each one formed by the association of a molecule of methanol with 5-carboxy-14-hydroxy-,(3,14,15,16,17,18,19,20) octadehydro-yohimban-21-one, a hitherto not described compound possessing the same ring skeleton as yohimbine and reserpine, two major indole alkaloids. The structure of a spiro derivative of 2,3,4,5-tetrahydro-s-carboline, previously proposed [16], can thus be eliminated.

Interaction Between Furocoumarins and Pyrimidine Bases in a Linked System. The Crucial Choice of the Link

Abstract A specific interaction between psoralen and pyrimidine bases (thymine), revealed in crystals of compound III, induced under UV light a topochemical photocycloaddition between the double bonds of thymine and pyrone ring of psoralen. The crystallographic analysis of compound I, II and III demonstrated the minor perturbation displayed by the trioxyethylene chain on the chromophore packing modes.

Solid state photodimerization of psoralen derivatives

Abstract Stereoselective reversible photodimerization of 8-alkoxypsoralen 1-thymine derivatives occurs in the solid state with topochemical control, the reactive pyrone double bonds of the monomers being favourably oriented in the crystal to produce only the exo head-to-tail dimer.

Crystal structure of 1,2‐[4‐butoxybenzoyloxy‐4′‐pentyl]diphenylethane

The crystal structure of 1,2‐[4‐butoxybenzoyloxy‐4′‐pentyl]diphenylethane (C30H36O3) has been determined by direct methods using single crystal X‐ray diffraction data. It crystallizes in the monoclinic system with space group P21/a and Z = 4. The unit cell parameters are: a = 8.098(1), b = 10.926(1), c = 29.643(2) Å and β = 94.01(1)°. The final reliability factor is R = 0.073 and the goodness of fit is equal to 1.027. The molecular arrangement is very typical, with molecules associated in dimers very closely parallel to the Oz axis. In a given dimer, the backbones of the two molecules run alongside each other; this association can be attributed to strong dipole–dipole interactions through the polar ester and ether groups. In addition these dimers are connected to neighbours via dipole–dipole interactions along the Oy direction. There are numerous very weak van der Waals interactions, particularly between the terminal aliphatic chains.

Topochemistry in Crystalline Imperfections.: The Photodimerization of Two Acenaphthylene Derivatives

Abstract The topochemical rule states that, in organic solids, the reactions occur with a minimum of atomic and molecular movements and are controlled by the crystalline structure of the starting materials.1 The photochemical behaviour of α and β modifications of trans cinnamic acid crystals is a good illustration of the topochemical concept, each crystalline form gives the stereoisomer expected from the idealized crystal structure.1

Isofenchylic alcohol derived from a functionalized pinene oxide: unexpected formation and structural confirmation using multi-dimensional NMR spectroscopy and x-ray crystallography

The complete proton and carbon‐13 assignment and the stereochemistry of (1R)(7S)(9R)(11S)‐11‐hydroxy‐8,8‐dimethyl‐6‐oxa‐5‐oxo‐3‐thiatricyclo[7.2.1.01,7]dodecane, a fenchylic derivative compound, was performed by using 1D and 2D NMR experiments (COSY, HMBC, HMQC, NOESY) leading to its unambiguous structural characterization. This structure was confirmed by an x‐ray crystallographic experiment. Copyright