4-Methylmorpholine → 7,8-Methylenedioxy-4-chromanone

Participants

Reaction Steps

To a solution of 2,3-methylenedioxyphenol (27 g) and N-methyl morpholine (19.6 g) in THF (100 ml) was added benzyl propiolate (38 g) over a period of 30 minutes with cooling. After the addition was complete the reaction was stirred at room temperature for 1.5 hours followed by concentration The residue was taken up into Et2O (500 ml), washed with 10% HCl (2×100 ml), dried over MgSO4. filtered and concentrated. This material was subjected to hydrogenation with 10%Pd/C in methanol at 4 atm. The reaction was filtered and concentrated. The resulting saturated acid was dissolved into methanesulfonic acid (350 ml) and stirred for 24 hours. The reaction was poured onto ice and extracted with CH2Cl2. The organic layer was washed with saturated Na2CO3, dried over MgSO4, filtered and concentrated to provide the desired material.

Provenance & Evidence