23 research outputs found
Neue ?-Lactam-Antibiotika. ïżœber Derivate der 3-Hydroxy-7-amino-ceph-3-em-4-carbonsïżœure. Modifikationen von Antibiotika, 10. Mitteilung [1]
Synthesis and Antibacterial Activity of 7ÎČ-[3-(Un)substituted-2-aminopropionamido]-3-vinylcephalosporins and Related Compounds
Synthesen biologisch wichtiger Kohlenhydrate, 8. Synthese der Evermicose (2,6-Didesoxy-3-C-methyl-D-arabino-hexose)
ComposĂ©s OlĂ©finiques et AcĂ©tylĂ©niques. IV. Nouvelles SynthĂšses du 1,3,5âHexatriene; ĂlectrodimĂ©risation de L'AcrolĂ©ine sur un Couple ZincâCuivre
The electrodimerisation of acroleine on a zincâcopper couple in the presence of acetic acid gives 1,5âhexadieneâ3,4âdiol 5 in 76% yield, the ratio meso/dl being 60/40. Gas chromatographic analysis of the reaction mixture reveals the presence of threoâ and erythroâ1âhexeneâ3,4âdiol and of the monoâ and diâacetates (meso/dl) of 4, especially when large quantities of acetic acid are used. Optimum conditions are described in order to minimize these sideâreactions. Starting from 4, two new routes to 1,3,5âhexatriene 1 has been developped, namely by treating the bistosylate derivative of 4 with sodium iodide in 2â(2âethoxyâethoxy) ethanol (adaptation of Linstead's reaction) and by a modification of Corey's method, where 4 is treated with NâČ, NâČâthiocarbonylâdiimidazole and the resulting cyclic thiocarbonate decomposed in triphenylphosphite. Hexatriene is obtained respectively in 52 and 47% overall yield, the cis/trans ratios being 10/90 and 20/80. Although these reaction schemes appear to be nonâstereospecific, they constitute two new valuable methods to cisâ1,3,5âhexatriene. Copyright © 1974 WileyâVCH Verlag GmbH & Co. KGaA, WeinheimSCOPUS: ar.jinfo:eu-repo/semantics/publishe