Yield:315228-46-7 29%

Reaction Conditions:

with sodium nitrite in sulfuric acid;water at 0; for 1 h;Heating / reflux;

Steps:

308 3-Hydroxy-6-methylquinoline (308)

A solution of 3-Amino-6-methylquinoline [(1.21 g, 7.65 mmol), prepared according to J. Chem. Soc. 2024-2027(1948) Morley, J. S.; Simpson, J. C. E.] in 6N H₂SO₄ (25 ml) was cooled in an ice bath. To the solution NaNO₂ (560 mg, 8.10 mmol) in water (2 ml) was added and stirred for 30 min at 0 degrees. Separately 5% H₂SO₄ was refluxed and above Diazo reaction mixture was added to this refluxing solution. After 30 min the reaction mixture was cooled to room temperature, and was neutralized by 6N NaOH. The resulting insoluble material was collected by filtration. This solid was recrystallized by CHCl₃/AcOEt to afford compound (308) (348 mg, 29%). ¹H NMR (300 MHz,DMSO-d₆) δ 7.34 (1H, dd, J=1.9, 8.6 Hz), 7.42(1H, d, J=2.8 Hz), 7.55 (1H, s), 7.79 (1H, d, J=8.6 Hz), 8.50 (1H, d, J=2.8 Hz).

References:

US2005/250820,2005,A1 Location in patent:Page/Page column 79