Dipropylamine → 5-Methoxy-N,N-dipropyl-3,4-dihydro-2H-1-benzopyran-3-amine

Participants

Reaction Steps

To a solution of 8-bromo-5-methoxy-3-chromanone (125 mg, 0.49 mmol) in benzene (20 ml) was added di-n-propylamine (0.5 ml, 3.7 mmol) and p-toluenesulfonic acid monohydrate (10 mg, 0.08 mmol). The solution was refluxed for 5 hours with a Dean-Stark apparatus under N2 -atmosphere. The reaction mixture was poured into a Parr-flask, absolute ethanol was added (50 ml) and pH was adjusted to 11 with 2M-NaOH-solution. The product was hydrogenated overnight with Pd/C as catalyst. The catalysst was filtered off and the solvent was evaporated. The residual oil was dissolved in CH2Cl2 and washed with 5% aqueous Na2CO3. The phases were separated and the organic layer was dried (Na2CO3) yielding 99 mg (77%) of the product as an oil with physical data identical with authentic material synthesized by alternative methods.

Provenance & Evidence