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931.
Jean DAngelo Jacqueline Ficini Serge Martinon Claude Riche Alain Sevin 《Journal of organometallic chemistry》1979,177(1):265-272
A cyclobutadiene—palladium complex, obtained by dimerization of an ynamine is described. The crystal structure of this compound shows, as salient feature, that the cyclobutadiene ring is not planar, but highly puckered. Anti-bonding interactions have been suggested as an explanation for this puckering. 相似文献
932.
The reaction of triethyloxonium tetrafluoroborate (Meerwein's reagent) with 2-oxo indoline 3-carboxanilides ( 4 ) gives mainly the 2-ethoxyindole derivatives, together with other C- and O-ethyl compounds. In the same time, difluoro indolyloxyboranes are formed by the reaction of the anilides 4 with boron trifluoride resulting from the decomposition, in situ, of the Meerwein's reagent. These results clearly indicate some limitation for synthetic applications of this reagent. 相似文献
933.
Alkyl diazoacetates react with N,N′-diisopropylcarbodiimide in the presence of transition metal salts (e.g. copper triflate or rhodium (II) acetate) to give 1-isopropyl-2-alkoxycarbonyl-3- isopropyliminio-aziridine in good yield. The reaction takes place at room temperature without formation of the formal dimer of the carbene (maleate and fumarate). 相似文献
934.
Doan Thi Mai H Gaslonde T Michel S Koch M Tillequin F Pfeiffer B Renard P Kraus-Berthier L Léonce S Pierré A 《Chemical & pharmaceutical bulletin》2004,52(3):293-297
A series of cis-1,2-dihydroxy-1,2-dihydrobenzo[b]acronycine diacid hemiesters and dicarbamates were prepared by acylation of cis-1,2-dihydroxy-6-methoxy-3,3,14-trimethyl-1,2,3,14-tetrahydro-7H-benzo[b]pyrano[3,2-h]acridin-7-one. The cytotoxicity of the dicarbamates depended on the steric hindrance of the esterifying groups at positions 1 and 2. Diacid hemiesters displayed significant in vitro cytotoxic activities and induced cell cycle perturbations similar to those obtained with cis-1,2-diacetoxy-1,2-dihydrobenzo[b]acronycine (S23906-1) currently under preclinical development. cis-1-Acetoxy-2-hemiglutaryloxy-1,2-dihydrobenzo[b]acronycine was the most promizing compound of the series, inducing complete inhibition of tumor growth when tested against C38 colon adenocarcinoma implanted in mice. 相似文献
935.
936.
Jean M. J. Tronchet Alain P. Bonenfant Franoise Perret Alberto Gonzalez Jean-Bernard Zumwald Ernesto M. Martinez Bruno Baehler 《Helvetica chimica acta》1980,63(5):1181-1189
Synthesis of Terminal Acetylenic Sugars Derivatives and Ynuronic Acids Derivatives by Use of a Wittig Reaction The method described for the preparation of terminal acetylenic sugars presents two advantages over earlier procedures: no new asymmetric center is created and the chain can be extended by one or more C-atoms. The method also allows preparation of ynuronic acids. The aldehydosugars derivatives 1–7 gave in good to excellent yields the corresponding gem-dibromoenoses 8–14 from which either the terminal acetylenic sugars derivatives 15–21 or the ynuronic acids 22–24 were easily prepared. A few examples of 1,3-dipolar cycloadditions (leading to 28–30 ) with these acetylenic sugar derivatives are also described. 相似文献
937.
Belaïd Diab Henri Jolibois Bernard Laude Stphane Golhen Lahcne Ouahab Alain Chambaudet 《Helvetica chimica acta》1999,82(5):779-789
One-Step Synthesis of Novel Heptacyclic Molecules Starting from 2-Aryl-4-methyl-1-benzopyrylium Salts. X-Ray Crystal Structures of These Compounds Containing a Methano-Bridged 1-Benzoxepine Fused to Two 1-Benzopyran Moieties The chemical reduction of 4-methyl-2-(ortho-hydroxyaryl)-1-benzopyrylium chlorides with Zn in MeCN and HCl led to a mixture of diastereoisomeric heptacyclic molecules. The structures of two of them were determined by X-ray analysis. These methano-bridged 1-benzoxepines fused to two 1-benzopyran moieties were formed from intermediate biflavene species. 相似文献
938.
Alain Krief Thierry Van Wemmel Martine Redon Willy Dumont Cathy Delmotte 《Angewandte Chemie (International ed. in English)》1999,38(15):2245-2248
The addition of elemental selenium to organolithium compounds 1 or organic selenates 2 gives organic diselenolates 3 . The reactions proceed by the insertion of two selenium atoms into the carbon–metal bonds or of one selenium atom into a selenolate. Evidence for the existence of n-butyldisilenol has also been obtained. 相似文献
939.
940.