Indole → 1-Aminoindole

Participants

Reaction Steps

A solution of 33.8 kg (32.8 kg corrected for 97% purity) of hydroxylamine-O-sulfonic acid (HOSA) and 15.8 kg (15.6 kg corrected for 99% purity) of indole in 120.2 kg of N-methylpyrrolidinone (NMP), is prepared and chilled to 0–5° C. A second solution is prepared from 67.0 kg (63.7 kg corrected for 95% purity) of potassium tert-butoxide and 122.6 kg of NMP. An amination vessel is charged with 47.0 kg of NMP and an initial charge of 2.2 kg of the potassium tert-butoxide/NMP solution. The HOSA/indole/NMP solution and the remaining potassium tert-butoxide/NMP solution are then simultaneously and proportionally metered using a metering pumping system consisting of a dual head plunger pump together with coriolis mass flow meters into the amination vessel over a period of 185 minutes while maintaining a reaction temperature of 20–30° C. to yield a solution containing 15.9 kg (90.2% yield) of 1H-indol-1-amine as determined by external standard HPLC assay.

Provenance & Evidence