Hydrochloric Acid → 4-Ethylquinolin-2(1H)-one

Participants

Reaction Conditions

Reaction Steps

1,2-Dihydro-4-methyl-2-oxoquinoline (79.5 g.) was dissolved in a mixture of dry hexamethylphosphoramide (530 ml.) and tetrahydrofuran (530 ml.), and the solution was cooled to -10° C. under a nitrogen atmosphere. n-Butyl-lithium (1.54 M solution in hexane; 770 ml.) was added to the stirred solution at such a rate as to keep the temperature below 0° C. When the addition was completed, the deep red solution was cooled to -50° C. and methyl iodide (50 ml.) was rapidly added. The resulting pale yellow solution was immediately poured into water (2000 ml.) and acidified to pH 1 with concentrated hydrochloric acid. The resulting mixture was filtered and the solid residue washed with water and then dried in vacuo over phosphorus pentoxide. Crystallisation from ethanol gave 4-ethyl-1,2-dihydro-2-oxoquinoline, m.p. 197° C.

Provenance & Evidence