Isoquinolin-5-ol → 5-Methoxyisoquinoline

To a solution of 5-hydroxyisoquinoline (10 g, 69 mmol) in MeOH (100 ml) was added a solution of sodium methoxide in methanol (30% by weight, 13.8 ml, 72.4 mmol) followed by phenyltrimethylammonium chloride (12.4 g, 72.4 mmol). The reaction mixture was stirred at room temperature for 2 h, after which time it was filtered and the filtrate evaporated under reduced pressure to afford an oil which was dissolved in DMF (50 ml ). The reaction mixture was refluxed for 2 h after which time the reaction mixture was evaporated under reduced pressure. The resulting oil was partitioned between CH2Cl2 and 1N aqueous NaOH, the organic layer was washed twice with 1N aqueous NaOH, dried over MgSO4 and evaporated under reduced pressure. The crude product was purified on silica gel eluting with EtOAc/hexane (1/1, v/v) to afford the subtitle compound as a yellow oil (6.11 g, 56%). 1H NMR (CDCl3) δ: 4.05 (3H, s), 7.00 (1H, d), 7.55 (2H, m), 8.02 (1H, d), 8.55 (1H, d), 9.22 (1H, s).

1. filtrationafter which time it was filtered
2. customthe filtrate evaporated under reduced pressure
3. customto afford an oil which
4. temperatureThe reaction mixture was refluxed for 2 h after which time the reaction mixture
5. customwas evaporated under reduced pressure
6. customThe resulting oil was partitioned between CH2Cl2 and 1N aqueous NaOH
7. washthe organic layer was washed twice with 1N aqueous NaOH
8. dry with materialdried over MgSO4
9. customevaporated under reduced pressure
10. customThe crude product was purified on silica gel eluting with EtOAc/hexane (1/1

ORD record

ord-226034bd84f746799978c8c91c9b4b28

Source dataset

uspto-grants-2003_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06653302B2