Yield:637347-71-8 99%

Reaction Conditions:

with sodium chlorite;sodium dihydrogenphosphate;2-methyl-but-2-ene in tetrahydrofuran;water;tert-butyl alcohol at 20; for 1 h;

Steps:

155.2 Compound 155b: 2-Chloro-3,4-dimethoxy-6-nitrobenzoic acid

In THF (100 mL) and t-butanol (100 mL)2-Methylbut-2-ene (387 mL, 774 mmol) was added at 10 ° C. to a solution of compound 155a (19 g, 77 mmol). To this solution was then added dropwise a solution of sodium chlorite (21.0 g, 232 mmol) and sodium dihydrogen phosphate (27.8 g, 232 mmol) in water (50 mL) and the suspension was added dropwise at room temperature And stirred vigorously for 1 hour. The mixture was then diluted with saturated aqueous NH 4 Cl solution and the product was extracted with DCM. The combined organic extracts were washed with brine, dried over Na 2 SO 4, filtered and concentrated in vacuo to give a yellow solid which was used in the next step without further purification (20 g, 99%).

References:

JP6377570,2018,B2 Location in patent:Paragraph 0773; 0774