p-Toluenesulfonic acid → HCID 9795142, compound

Participants

Reaction Steps

0.1 g of p-toluenesulfonic acid was added to a solution of 1.5 g of 3-trifluoroacetamidomethyl-5-hydroxymethyl-3,4,5,6-tetrahydro-6-oxo-1H-azepino[5,4,3-cd]indole (see Example 11C for preparation) in 25 ml of methanol, and the solution was heated under reflux for 2 hours. The reaction mixture was then concentrated, and saturated aqueous potassium carbonate solution was added to the residue until a pH of 11 was reached, and the mixture was stirred at room temperature for 4 hours. The treatment with the saturated aqueous potassium carbonate solution eliminated the trifluoroacetyl protective group and neutralized the p-toluenesulfonic acid. To work up the reaction mixture it was subsequently evaporated to dryness, the residue was taken up in methanol, insoluble components were removed by filtration, and the residue on the filter was washed twice more with 30 ml portions of methanol. The combined methanol phases were evaporated and the residue was purified by chromatography under moderately elevated pressure (=low-pressure chromatography under 3 to 6 bar) on silica gel using methanol/25% strength aqueous ammonia solution 97:3 as eluent. The title compound which remained after concentration of the eluate was crystallized from ethanol/ether 9:1. 0.5 g of 3-aminomethyl-5-methoxymethyl-3,4,5,6-tetrahydro-6-oxo-1H-azepino[5,4,3-cd]indole was obtained with a melting point of 160° to 163° C.

Provenance & Evidence