3,4-dihydro-2H-pyran → 5-(Tetrahydropyran-2-yloxy)-2-trifluoroacetyl-1,2,3,4-tetrahydroisoquinolin

Participants

Reaction Steps

3.7 g (15.9 mmol) of 5-hydroxy-2-trifluoroacetyl-1,2,3,4-tetrahydroisoquinoline (Example 1) and 4.4 mL (47.7 mmol) 2,3-dihydropyrane were dissolved in dichloromethane and catalytic amount of p-toluenesulfonic acid monohydrate was added. After completion of the reaction (System A), the reaction mixture was diluted with dichloromethane, washed with water and aqueous sodium chloride. The solution was dried over Na2SO4, evaporated to dryness, and the product was purified by silicagel chromatography (System A). Yield 4.13 g, 79%. 1H NMR (CDCl3, 400 MHz): 7.16 (1H, m), 7.00 (1H, m), 6.77 (1H, m), 5.45 (1H, m), 4.79 (2H, ss), 3.8 (3H, m), 3.6 (1H, m), 2.9 (4H, m).

Provenance & Evidence