1,1'-Carbonyldiimidazole → HCID 489423, compound

Participants

Reaction Steps

1,1'-carbonyldiimidazole (0.42 g) is added to a 20°-25° solution of 5-chloroindole-2-carboxylic acid (I, 0.5 g) in THF (5 ml). After 1 hour of stirring at 20°-25°, the above reaction is added dropwise over 10 minutes via cannula to a -10° (ice/acetone bath) solution of [3-(ethylamino)-2-pyridinyl]piperazine (II, 0.58 g) in THF (5 ml). After 30 minutes of stirring at -10°, the reaction is warmed to 20°-25° and stirring is continued for 5 hours. The reaction is diluted with dichloromethane (50 ml), washed with saturated aqueous sodium bicarbonate (40 ml), water (40 ml) and saline (40 ml). The organic layers are dried over anhydrous sodium sulfate and concentrated under reduced pressure. The concentrate is purified by flash column chromatography (50 g silica gel), eluting with ethyl acetate/hexane (1/1). The appropriate fractions are pooled and concentrated to give the title compound, mp 208°-209°; IR (mineral oil) 3200, 2920-3000, 1632, and 1425 cm-1 ; NMR (300 MHz, CDCl3) 9.77, 7.72, 7.60, 7.36, 7.22, 6.97, 6.86, 6.75, 4.23, 4.09, 3.23-3.15, and 1.33 δ; MS (m/e) 383, 178, 176, 162, 150, 148, 137, 134, and 120.

Provenance & Evidence