Hydrochloric Acid → 2-Hydroxyquinoline

Participants

Reaction Conditions

Reaction Steps

Quinolinone I was synthesized from commercially available 2-chloromethyl-4-benzyl morpholine, methylamine, 4-chloro-2-nitroaniline, and 2-amino-6-fluorobenzonitrile following the general procedure of Example 49. (2-(methylamino)methyl-4-benzyl morpholine was dissolved in an 8 M solution of NH2Me in EtOH and heated in a glass bomb at 110° C. overnight to form the product 2-(methylamino)methyl-4-benzyl morpholine following removal of the solvent). Compound I (1.0 equivalent) and 10% Pd/C (0.1 equivalents) were suspended in 1:1 ethanol and 1 N aqueous HCl at room temperature. The reaction flask was evacuated and subsequently filled with H2. The resulting mixture was stirred under a hydrogen atmosphere overnight, filtered through Celite, and concentrated under vacuum. The solution was made basic with 30% aq. KOH and the product was extracted with EtOAc. The combined organic layers were concentrated and resuspended in CH2Cl2:MeOH:AcOH (2:2:1). Paraformaldehyde (1.2 equivalents) and BH3 pyridine (3 equivalents, 8 M) was then added and the mixture was stirred overnight at room temperature. The solvent was removed in vacuo and washed with water. The aqueous layer was extracted with EtOAc (3×), and the combined organic layers were concentrated and purified by silica gel chromatography (10% MeOH/CH2Cl2) to afford the desired product. MH+=437.4.

Provenance & Evidence