Collect. Czech. Chem. Commun. 2006, 71, 679-690

A Study of 5-Nitroindole Alkylation

Václav Kozmíka, Bedřich Košataa, Jiří Svobodaa,* and Miroslav Kuchařb

a Department of Organic Chemistry, Institute of Chemical Technology, Prague, 166 28 Prague 6, Czech Republic
b Zentiva, 102 01 Prague 10, Czech Republic


A detailed study of the 5-nitroindole alkylation, the key step in the synthesis of Zafirlukast, is presented. A broad distribution of alkyl derivatives has been found. 2,3- And 1,3-dialkylindoles can be selectively obtained in a ZnBr2-catalyzed reaction. Structure of all the products was fully assigned.

Keywords: Indoles; Alkylations; Lewis acid catalysis; Electrophilic substitutions; Friedel-Crafts alkylation; Leukotriene antagonists.

References: 33 live references.