Yield:89794-06-9 70%

Reaction Conditions:

with hydrogenchloride;sulfur dioxide;acetic acid;copper(l) chloride;sodium nitrite in water at 0; for 3 h;

Steps:

1 Example 1 Preparation of Compound II-1

In the reaction vessel, glacial acetic acid (300 mL) and cuprous chloride (13.9 g) were sequentially added, and sulfur dioxide gas was introduced at room temperature for 1 hour, and the temperature was lowered to 0 to obtain a reaction liquid A;In another reactor, Compound I-1 (13.0 g) was added in order,Glacial acetic acid (100 mL) and concentrated hydrochloric acid (12 mL) were stirred and cooled to 0 °, sodium nitrite (5.3 g) was added, and stirred for 1 hour to obtain a reaction liquid B; at 0 degree, the reaction liquid B was added to the reaction liquid A. The mixed reaction solution was stirred for 2 hours, extracted with ethyl acetate, and the combined organic layer was washed with water, dried over anhydrous sodium sulfate, filtered, concentrated, and purified by column chromatography to afford compound II-1 (yellow solid, 13.3 g, yield 70%).

References:

CN108752375,2018,A Location in patent:Paragraph 0093; 0094; 0095