Methanol → HCID 58745798, compound

Participants

Reaction Conditions

Reaction Steps

A 3 L three-necked flask equipped with a mechanical stirrer was charged with indole 6-carboxylic acid (220 g, 1.365 mole) and KOH pellets (764.45 g, 13.65 mole, 10 equivalents). Water (660 mL) and MeOH (660 mL) were added and the mixture heated to 75° C. Cyclopentanone (603.7 mL, 6.825 mole, 5 equivalents) was added dropwise over 18 h using a pump. The reaction mixture was heated for an additional 3 h (after which the reaction was judged complete by HPLC) and cooled to 0° C. for 1 h. The precipitated potassium salt is collected by filtration, and washed with TBME (2×500 mL) to remove cyclopentanone self-condensation products. The brown solid was re-dissolved in water (2.5 L) and the solution washed with TBME (2×1 L). Following acidification to pH 3 with conc. HCl (425 mL), the beige precipitate was collected by filtration, washed with water (2×1 L) and dried under vacuum at 70° C. The crude product weighed 275.9 g (88.9% mass recovery) and had an homogeneity of 85% (HPLC).

Provenance & Evidence