2-Cyclohexylacetaldehyde → 3-Cyclohexyl-quinoline-5-carboxylic acid

Participants

Reaction Steps

A mixture of 50 g of 4-nitro-3-hydroxyphthalide in 200 ml of isopropanol is hydrogenated with 5 g of Pd/barium sulphate under 3.5 bar, during which the temperature rises to 55° C. When the hydrogenation has ended (about 30 minutes), the catalyst is filtered off hot with suction. 33 g (260 mmol) of cyclohexylacetaldehyde are added to the filtrate and, after addition of a catalytic amount of sodium methylate, the mixture is heated under reflux for 20 hours. After cooling, the crystals which have precipitated out are filtered off with suction and washed with isopropanol. 15 g of virtually colourless product with a melting point of over 280° C. are obtained.

Provenance & Evidence