摘要:
A process is described for the preparation of arylpyridine compounds by aryl-aryl cross-coupling reactions between a halopyridine and an arylmagnesium halide carried out in the presence of a catalytic amount of a zinc salt and a catalytic amount of palladium. The zinc salt is preferably selected from ZnCl2, ZnBr2 and/or Zn(OAc)2, while the palladium is preferably used in the form of Pd(PPh3)4 or Pd(OAc)2 +4 PPh3. The reaction can also be carried out in the presence of bidentate phosphines, such as, for example, 1,3-bis(diphenylphosphine)propane or 1,4-bis(diphenylphosphine)-butane. It is thus possible to obtain molar yields higher than 97% (calculated relative to the halopyridine) and a catalyticity of more than 2000.
摘要:
A process for the preparation of 5-amino-2,4,6-triiodoisophthalic acid dichloride by chlorination of 5-amino-2,4,6-triiodoisophthalic acid with thionyl chloride in the presence of a suitable solvent characterized in that the reaction is carried out in the presence of catalytic amounts of a tetraalkylammonium salt of formulaR.sub.1 R.sub.2 R.sub.3 R.sub.4 NX (I)wherein X is halogen, mesylate or tosylate; R.sub.1, R.sub.2, R.sub.3 and R.sub.4, the same or different, are C.sub.1 -C.sub.20 alkyl groups so that the total number of carbon atoms of the groups R.sub.1, R.sub.2, R.sub.3 and R.sub.4 is higher than 16.The 5-amino-2,4,6-triiodoisophthalic acid dichloride obtained according to the process of the present invention is useful as intermediate in the synthesis of iodinated contrast media.
摘要翻译:通过在合适的溶剂存在下,用亚硫酰氯氯化5-氨基-2,4,6-三碘代邻苯二甲酸制备5-氨基-2,4,6-三碘代邻苯二甲酸二氯化物的方法,其特征在于反应是 在催化量的式R 1 R 2 R 3 R 4 N X(I)的四烷基铵盐的存在下进行,其中X是卤素,甲磺酸酯或甲苯磺酸酯; R 1,R 2,R 3和R 4相同或不同,为C 1 -C 20烷基,使得R 1,R 2,R 3和R 4基团的总碳原子数高于16.将5-氨基-2,4 根据本发明方法获得的6-三碘间苯二甲酰氯可用作合成碘化造影剂的中间体。
摘要:
A process for the preparation of 2-(2-fluoro-4-biphenyl)propianic acid enantiomers comprising a II order resolution of ketals of formula ##STR1## wherein R.sub.1 ad R.sub.2 have the meanings reported in the description; the asterisk shows the chiral carbon atom and the asymmetric carbon atoms marked by .alpha. and .beta. have both R or S configuration is described.