Sulfuric Acid → 7-Methoxyquinolin-8-ol

Participants

Reaction Steps

Finely ground 7,8-dimethoxyquinoline-2-carboxylic acid (1.00 g, 4.3 mmol) (W. Ried, A. Berg and G. Schmidt, Chem. Ber., 85, 204 (1952)) was heated under nitrogen in a flask submerged in an oil bath at 185° until the evolution of gases had ceased from the melt. The reaction was cooled and 75% aqueous sulfuric acid (8.1 mL) was carefully added. The resulting solution was heated at 105°-125° for 2 hr, cooled, poured over ice and taken to pH 5 with 5N sodium hydroxide. The mixture was filtered, and the filtrate was extracted with methylene chloride (4×50 mL). The extracts were dried (MgSO4) and concentrated in vacuo to give 8-hydroxy-7-methoxyquinoline (0.40 g, 53%), mp 113°-115° after recrystallization from 95% ethanol. Anal. Calcd for C10H9NO2 : C, 68.56; H, 5.18; N, 8.00. Found: C, 68.33; H, 5.17; N, 7.97.

Provenance & Evidence