Tetrahydrofuran → 4-(but-3-enyl)-2-chloro-7-phenyl-6,7-dihydro-5H-cyclopenta[d]pyrimidine

Participants

Reaction Conditions

Reaction Steps

A 250 mL three-neck round bottom flask equipped with a refluxed condenser and nitrogen inlet was charged with 2,4-dichloro-7-phenyl-6,7-dihydro-5H-cyclopenta[d]pyrimidine (2 g, 7.54 mmol), Fe(acac)2 (0.400 g, 1.131 mmol), THF (84 mL) and NMP (6.4 mL). The resulting solution was cooled to −78° C. and but-3-enyl magnesium bromide was added (20 mL) dropwise over twenty min. During the addition, the color of the reaction mixture changed from deep red to brown. After stirring for 1 h at −78° C., another 20 mL of but-3-enyl magnesium bromide was added and stirred for further 1 h. The reaction mixture was allowed to warm to 0° C. and quenched with saturated ammonium chloride solution (250 mL). It was then extracted with MTBE (2×200 mL), washed with brine (25 mL), dried over anhydrous sodium sulphate and concentrated in vacuo to get a crude brown oil. It was purified by a Teledyne Isco instrument using a 40 g silica column and 4-7% ethyl acetate in pet ether to get 4-(but-3-enyl)-2-chloro-7-phenyl-6,7-dihydro-5H-cyclopenta[d]pyrimidine (1.1 g, 51.2%). LC-MS (M+H)+=285.2. 1H NMR (400 MHz, CDCl3) δ ppm 7.33-7.24 (3H, m), 7.14-7.12 (2H, m), 5.89-5.83 (1H, m), 5.09-5.00 (2H, m), 4.37 (1H, t, J=7.2 Hz), 3.04-3.01 (1H, m), 2.94-2.92 (1H, m), 2.85-2.81 (2H, m), 2.71-2.66 (1H, m), 2.55-2.51 (2H, m), 2.23-2.19 (1H, m).

Provenance & Evidence