Abstract

A new and facile synthesis of 5-((9H-carbazol-4-yloxy) methyl)oxazolidin-2-one intermediate towards the synthesis of carvedilol, a -adrenergic blocking agent

Author(s): K.Chinnam Naidu, V.Kiran Kumar, E.Naresh, Ch.Kameswararao, G.Madhusudhan, K.Mukkanti

Afacile synthesis of 1-(9H-carbazol-4-yloxy)-3-halopropan-2-ol, (6) and 5- ((9H-carbazol-4-yloxy) methyl)oxazolidin-2-one, (5) intermediates is described. These intermediates are utilized for the synthesis of Carvedilol. While synthesizing the new intermediate (5), observed formation of major impurity characterized as 4-((9H-carbazol-4-yloxy)methyl)-1,3-dioxolan-2- one, (9) and confirmed by its preparation. Reaction conditions were identified to minimize the impurity 9 formation to achieve good reaction conversionwhilemaking (5). This approach avoids the formation of bis compound (disclosed inEUROPEANPHARMACOPOEIA6.0, volume 2.0 as impurity B). This approach could be useful for the preparation of many -amino alcohols without formation of bis impurity.