Hydrochloric Acid → 3-(Quinolin-6-yl)propanal

Participants

Reaction Conditions

Reaction Steps

A solution of 6-(3,3-diethoxypropyl)quinoline (23, Method A of Example 16, 520 g , 2.08 mol, 1.0 equiv) in ethyl acetate (EtOAc, 2.2 L) was cooled to 0° C. before a 2 N aqueous hydrochloric acid (HCl) solution (2.2 L) was added over 1 h while keeping the reaction temperature below 5° C. The resulting reaction mixture was stirred for an additional 2 h at 0-5° C. When TLC and HPLC/MS indicated the reaction was complete, the reaction was quenched with an ice cold 3 N aqueous sodium hydroxide (NaOH) solution at 0° C. until the pH was between 8 to 9. The layers were separated and the aqueous layer was extracted with ethyl acetate (EtOAc, 2 L). The combined organic layers were washed with brine (2 L), dried with sodium sulfate (Na2SO4), and concentrated under the reduced pressure to afford crude 3-(quinolin-6-yl)propanal (9, 385.3 g, 385.3 g theoretical, 100%) as a yellow oil, which was found to be identical to the material obtained from Method 1 in every comparable aspect. Since this crude material was found to be sufficiently pure, it was used directly in subsequent reaction without further purification.

Provenance & Evidence