Propionyl chloride → 3-(N-n-propylamino)chroman

Participants

Reaction Steps

Propionyl chloride (1.1 g, 11.5 mmol) was added to a mixture of 14 (1.2 g, 8.0 mmol) in CH2Cl2 and 10% aqueous Na2CO3 and stirred for 2 hours. Additional propionyl chloride (1.1 g, 11.5 mmol) was added and the mixture stirred overnight. The phases were separated and the organic layer was dried (MgSO4). The solvent was evaporated and the crude amid was treated with LiAlH4 (1 g, 26.4 mmol) in dry THF for 8 hours at room temperature. Since the reduction was not completed, additional LiAlH4 (0.5 g, 13.2 mmol) was added and the mixture refluxed for 1 hour. Excess of hydride was quenched by addition water (1.5 ml), 15% NaOH (1.5 ml) and water (4.5 ml). The mixture was filtered and the solvent evaporated yielding 1.1 g (72%) of 3-(N-n-propylamino)chroman (15) as an oil. The amine was converted to its hydrochloride with HCl-saturated EtOH and recrystallized from EtOH-ether. m.p. 203° C.

Provenance & Evidence