HCID 16113114, compound → Isoquinoline

Temperature

0 °C

To a suspension of 2-methyl-4,6-dimethoxy benzoic acid (2.8 g, 14.27 mmol) in CH2Cl2 (30 mL), oxalyl chloride(3.62 g, 28.54 mmol) was added and the mixture was stirred at rt for 16 h. The solvent and excess of oxalyl chloride were removed at reduced pressure. The solid was dissolved in CH2Cl2 (10 mL) and methyl amine hydrochloride (1.33 g, 42.81 mmol) was added on cooling and the mixture was stirred at rt for 4 h. The solvent was removed and the crude product was purified by chromatography by using 5% methanol in CH2Cl2, to give 1.3 g of the amide intermediate in 43% yield. To a solution of the amide intermediate (1.29 g, 6.16 mmol) in THF (30 mL), n-butyl lithium (5.6 mL, 14.18 mmol, 2.5 M solution in hexane) was added slowly under N2 with cooling( ice-salt bath) maintaining the temperature below 20° C. The mixture was stirred for 1 h at 0° C., then cooled to −50° C. and a solution of 4-O-TBDMS-benzonitrile (1.58 g, 6.78 mmol) in THF (10 mL) was added quickly. The cooling bath was removed and allowed to warm to rt and stirred for 16 h at rt. Saturated aqueous NH4Cl solution was added with cooling , and the layers were separated. The organic layer was washed with water, brine, dried over Na2SO4 and concentrated to give the crude intermediate, which was purified by chromatography using 5% methanol in CH2Cl2, to give two products (1) 678 mg of isoquinoline in 26% yield and (2) 780 mg of quinalone product in 27% yield. To a suspension of the above quinalone product (2) (780 mg, 1.65mmol) in ethanol (20 mL), conc. HCl (2 ml) was added and the mixture was heated at 70° C. for 2 h. The reaction mixture was cooled to rt and the solvent was removed and purified by chromatography using 5% methanol in CH2Cl2 to give 3-(4-hydroxyphenyl)-6,8-dimethoxyisoquinolin-1(2H)-one (215 mg, 44%). MS (ES) m/z: 297.93 (M); Mp. 245-247° C.

1. temperaturemaintaining the temperature below 20° C
2. temperaturecooled to −50° C.
3. customThe cooling bath was removed
4. temperatureto warm to rt
5. stirringstirred for 16 h at rt
6. additionSaturated aqueous NH4Cl solution was added
7. temperaturewith cooling
8. customthe layers were separated
9. washThe organic layer was washed with water, brine
10. dry with materialdried over Na2SO4
11. concentrationconcentrated
12. customto give the crude intermediate, which
13. customwas purified by chromatography

ORD record

ord-8e24664c5523418b9ee518249d44fadb

Source dataset

uspto-grants-2012_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08093273B2