5-Methoxyindole → hydroxylamine-O-sulfonic acid

Participants

Reaction Steps

A solution of 10.0 g (9.7 g corrected for 97% purity) of hydroxylamine-O-sulfonic acid (HOSA) in 33.7 g of N-methylpyrrolidinone (NMP) is prepared and chilled to 0–5° C. A second solution is prepared from 20.1 g (19.1 g corrected for 95% purity) of potassium tert-butoxide and 34.4 g of NMP. An amination vessel is charged with 5.9 g of 5-methoxyindole, 17.8 g of NMP and an initial charge of 0.7 g of the potassium tert-butoxide/NMP solution. The HOSA/NMP solution and the remaining potassium tert-butoxide/NMP solution are then simultaneously and proportionally metered into the amination vessel over a period of 86 minutes while maintaining a reaction temperature of 15–22° C. to yield a solution containing 5.6 g (87% yield) of 5-methoxy-1H-indol-1-amine as determined by internal standard HPLC assay.

Provenance & Evidence