Yield:7509-13-9 803 mg

Reaction Conditions:

with water;sodium hydroxide in tetrahydrofuran;methanol at 10 - 35; for 12 h;

Steps:

99 1-oxo-1,2-dihydroisoquinoline-3-carboxylic acid

Reference Example 99
1-oxo-1,2-dihydroisoquinoline-3-carboxylic acid
To a mixed solution of methyl 1-oxo-1,2-dihydroisoquinoline-3-carboxylate (914 mg, synthesized by a method described in Tetrahedron Lett., 1999, 40, 7935) in THF (10 ml)-methanol (10 ml) was added 1N aqueous sodium hydroxide solution (10 ml), and the mixture was stirred at room temperature for 12 hrs.
The reaction mixture was acidified with 1N hydrochloric acid and the mixture was extracted with ethyl acetate.
The organic layer was washed with saturated brine, dried and concentrated.
The obtained crude crystals were washed with diisopropy ether to give the title compound (803 mg).
¹HNMR (CDCl₃) δ: 7.40 (1H, s), 7.59-7.69 (1H, m), 7.79 (1H, dt, J=1.4 Hz, 7.5 Hz), 7.88 (1H, d, J=7.0 Hz), 8.25 (1H, d, J=7.6 Hz), 10.90 (1H, br a).

References:

US2015/329556,2015,A1 Location in patent:Paragraph 1783-1784