7-Bromo-4-chloro-cinnoline synthesis

Yield:-

Reaction Conditions:

with hydrogenchloride;NaNO₂ in lithium hydroxide monohydrate at 0 - 70; for 12.5 h;

Steps:

3.8-4.8 Step VIII

A compound 3a (288 mg, 1.35 mmol, 1 eq) was added into hydrochloric acid (5.00 mL) and water (1.00 mL); then the aqueous solution (1.00 mL) of sodium nitrite (102 mg, 1.48 mmol, 1.1 eq) was dropped at 0°C for stirring for 30 min at this temperature, and the temperature was risen to 70°C for stirring for 12 hours. After the reaction was completed, water (20.0 mL) was added for dilution and filter. The filter cake was decompressed and concentrated to obtain a compound 3b. (0107) MS-ESI calculation values [M+H]⁺ 225, 227; actual measurement values 225, 227. (0108) ¹H NMR (400 MHz, DMSO-d₆) δ:13.53 (br s, 1H), 7.95 (d, J=8.8 Hz, 1H), 7.80-7.73 (m, 2H), 7.56 (dd, J=1.6, 8.7 Hz, 1H).

References:

EP3992189,2022,A1 Location in patent:Paragraph 0087; 0106-0108