Thionyl Chloride → HCID 178431738, compound

Participants

Reaction Steps

A mixture of 2-hydroxy-3-methylquinoline-4-carboxylic acid (V, Step II, 5.11 g) and thionyl chloride (35 ml) is stirred at reflux for 3.5 hr. After cooling, the excess thionyl chloride is removed under reduced pressure. The residue is taken up in dichloromethane and taken to dryness again under reduced pressure. The dichloromethane addition/removal under reduced pressure is repeated twice. The residue is then dried under greatly reduced pressure for 1 hr to remove the last traces of thionyl chloride to give 2-hydroxy-3-methylquinolin-4-oyl chloride (V-A), which is taken up in 30 to 40 ml of dichloromethane and cooled at 0°. Triethylamine (3.50 ml) is added, followed by pyrrolidine (4.19 ml). After 5-10 min the ice bath is removed. After stirring for 3 hr, the mixture is partitioned between dichloromethane and aqueous sodium bicarbonate. The mixture is filtered through sodium sulfate and concentrated to a residue. The residue is chromatographed (silica gel; methanol/dichloromethane (4/96)) to give pyrrolidino 2-hydroxy-3-methylquinoline-4-carboxamide (VI), mp 175°-176° which is crystallized from acetone, mp 223°-227°.

Provenance & Evidence