3- Chloroacetyl-1 -methoxyindole

Friedel-Crafts acylation of 77b with chloroacetyl chloride and AICI3 in nitrobenzene provides cleanly methyl 5-chloroacetyl- (90a, 52%) and 6-chloroacetyl-l-methoxyindole-3-carboxylates (91a, 20%) with the ratio of 2.5 1 (Scheme 11) [28]. Under similar reaction conditions, Nakatsuka and co-workers reported the chloroacetylation of methyl l-methylindole-3-carboxylate (89) to give 90b and 91b in the ratio of 3 1 [29]. Comparing these results with ours, it would be safe to conclude that the introduction of a methoxy group onto the N(l) prefers the 6- to 5-substitution in Friedel-Crafts acylation. 

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