Anne-Marie Lamazouere

ACTION D'ISOTHIOCYANATES SUR LES CARBANIONS DÉRIVÉS D'α-ALCOYL PYRIDINES ET D'α-ALCOYL QUINOLEINES STRUCTURE CRISTALLINE DE L'α,α',-di (N-PARATOLYLTHIOCARBOXAMIDE) PICOLINE-2

Carbanions derived from 2-alkyl pyridines and 2-alkyl quinolines react with one or two molecules of isothiocyanate, depending upon the carbanion and isothiocyanate structures. Thiocarboxamides 12, 13, or dithiocarboxamides 1, 3, 5, 7, 9, 11, are obtained. When dithiocarboxamides are formed, cyclisation occurs by further oxidation giving a dithiolan derivative. A single crystal structure study of one of these dithiocarboxamides was carried out. The crystals belong to space group P2(1)/c, with a = 12.874 (1), b = 10.867 (1), c = 15.624 (1) angstrom, beta = 109.13 (1)-degrees, Z = 4, M = 389.54, D(x) = 1.253 g cm-3, mu = 2.3 mm-1, F (000) = 816. The packing of molecules show stocking with two hydrogen bonds: N-H . . . N (N-N distance 2.673 angstrom) and N-H . . . S (N-S distance 3.338 angstrom).

Synthèse De 3-[Di(Alkylthio) MÉthylène] Nopinones Chirales. Dichroïsme Circulaire: Une Anomalie À La RèGle De l'HéLicité. Structure Cristalline De La (1R,5R)-( )-3-(1',3'-Dithiane-2'-Ylidène) Nopinone

Some chiral 3-[di(alkylthio)methylene] nopinones have been synthetized from (+)-nopinone by action of carbon disulfide, then alkyl halides in basic media and the molecule structure of one of these compounds was carried out by single crystal X-Ray diffraction methods. Crystals belong to space group P2(1) with a = 7.2330 (13), b = 7.872 (7), c = 11.8897 (11) Angstrom, beta = 106.650 (8)degrees, Z = 2, M = 254.39, D-c = 1.303 g.cm(-3), mu = 3.523 mm(-1), F (000) = 272. Circular dichroism of the pi --> pi(*) transition of these compounds is positive and opposite to those of the other alpha,beta-ethylenic derivatives of the nopinone. The presence of the two sulfur atoms and the distorsion of the whole conjugated system shown by the XR study could be responsible for this apparent anomaly.

SYNTHESE ET ETUDE D'UN THIA-6a THIOPHTENE CHIRAL (-)-DI(TRIMETHYL-1′,2′,2′ CYCLOPENTYLENE-1′,3′)-(2,3)-(4,5) THIA-6a THIOPHTENE STRUCTURE CRISTALLINE ET MOLECULAIRE

Abstract A chiral 6a-thiathiophten has been synthesized from (+)-2-bornanone and the molecular structure determined by single crystal X-ray diffraction methods. The compound crystallized in monoclinic system with space group P21, a = 10.883(2), b = 13.843(7), c= 13.645(5)A, V=2055A3, A3 = 4, Dc= 1.217g cm−3. Two independent molecules exist in the unit cell. Bond lengths and angles have nearly identical values in these two molecules. The central heterocycle is somewhat distorted with the Sl-S6a-S6 angle less than 180°. Besides, NMR 1H, 13C, UV spectra and circular dichroism (CD) were completed. A supplementary proof is given for the existence of double bonds, S1-C2 and C4-S6. CD measurements show that all transitions in the visible and ultraviolet regions present Cotton effect due to the chiral environment. The weak distortion of the central heterocycle could explain the forms of CD curves. Un thia-6a thiophtene a ete synthetise, a partir de la (+)-bornanone-2 et sa structure cristalline etablie par diffra...