Hydrochloric Acid → HCID 12802705, compound

Participants

Reaction Steps

A solution of 1-(4-chlorobenzyl)-1,2-dihydro-4-methyl-2-oxoquinoline (18.0 g.) in diethyl carbonate (80 ml.) was added to a stirred suspension of sodium hydride (15.4 g.; weighed as a 60% w/w dispersion in oil, but subsequently washed by decantation with light petroleum, b.p. 40°-60° C., to remove the oil) in diethyl carbonate (20 ml.). The mixture was stirred under reflux for 11/2 hours, and formed a thick suspension. This was cooled and treated with a small amount of methanol to destroy any remaining sodium hydride. Dilution with ether (400 ml.) gave a suspension from which the solid was filtered. This was suspended in ethanol (180 ml.) and brought to pH 3 by addition of hydrochloric acid. Water (600 ml.) was added, and the suspension was stirred for 30 minutes before the solid was collected by filtration, washed with water, and well drained. This solid [which comprised diethyl 1-(4-chlorobenzyl)-1,2-dihydro-2-oxoquinol-4-ylmalonate] was dissolved in ethanol (180 ml.), to which was added aqueous 40% w/v sodium hydroxide (20 ml.), and the mixture was heated under reflux for 4 hours. The cooled mixture was added to water (600 ml.) to give a solution which was brought to pH 3 by addition of concentrated hydrochloric acid. The resultant precipitate was collected by filtration, washed with water, drained, and crystallised from ethanol to give 1-(4-chlorobenzyl)-1,2-dihydro-2-oxoquinol-4-ylacetic acid, m.p. 208°-209° C., in 51% overall yield.

Provenance & Evidence