p-Toluenesulfonic acid → Pirandamine

Participants

Reaction Conditions

Reaction Steps

To a solution of 1-dimethylamino-3-butanone (1.0 g) dissolved in toluene (10 ml), p-toluenesulfonic acid (1.3 g) is added. The suspension is stirred for 10 min. Indene-3-ethanol (1.0 g) in toluene (5 ml) is added to the suspension and the resulting solution stirred for 2 hr. Boron trifluoride etherate (0.25 ml) is added together with ca. 0.5 g of hydrated alkali-aluminum silicate. The mixture is heated at 80° C for 30 min. The mixture is cooled and diluted with water. The organic layer is separated and the aqueous layer extracted with toluene. The organic layers are washed with water. The combined aqueous phase is rendered alkaline with conc.NH4OH and extracted with toluene. The latter extract is treated with charcoal and then concentrated to afford the title compound, identical to the compound of the same name described in Example 284.

Provenance & Evidence