Tributylphosphine → 8-(1-isopropylpiperidin-4-yloxy)-3,4-dihydropyrazino[1,2-a]indol-1(2H)-one

Participants

Reaction Conditions

Reaction Steps

To the suspension of 1.0 g (4.9 mmol) 8-hydroxy-3,4-dihydro-2H-pyrazino[1,2-a]indol-1-one in 70 ml tetrahydrofuran, a solution of 0.92 g (0.64 mmol) 1-isopropyl-piperidin-4-ol (commercially available) in 25 mL tetrahydrofuran, and 2.4 mL (2.0 g, 9.9 mmol) tributylphosphine were added. Another 20 mL tetrahydrofuran was added, and then the suspension was cooled to 0° C. Within 60 min., 2.5 g (9.9 mmol) 1,1′-(azodicarbonyl)dipiperidine was added under stirring and the reaction was allowed to reach room temperature. After 16 hours the suspension was filtered and the filtrate was evaporated. The residue was flash-chromatographed two times on silica gel with dichloromethane:methanol:ammonia (9:1:0.1 v/v) to give 0.43 g (26%) of the product as a light brown solid.

Provenance & Evidence