The bromination-methanolysis of N-acetyl-2,3-dimethylindole

Article abstract of DOI:10.1139/v82-181

Bromination of N-acetyl-2,3-dimethylindole 11 in the presence of excess methanol at room temperature gave a mixture of products consisting of cis and trans N-acetyl-2,3-dimethoxy-2,3-dimethylindoline 17 and 18, 3-methoxy-2,3-dimethylindoline 19, and N-acetyl-3-methoxymethyl-2-methylindole 21.The same reaction performed at -40 degC yielded a mixture of 17, 18, and N-acetyl-2-methoxy-2-methyl-3-methyleneindoline 22.Bromination of 11 at low temperature in the presence of 1.5 equivalents of methanol followed by treatment with triethylamine yielded 22 quantitatively.Treatment of 22 with acidic methanol readily gave 21.The mechanistic implications of these transformations are considered.