7-Benzothiazolecarboxylicacid,2-methyl-,methylester(9CI) synthesis

Yield:192948-01-9 75%

Reaction Conditions:

with potassium tert-butylate;copper(l) iodide;1,10-Phenanthroline in 1,2-dimethoxyethane; for 24 h;Inert atmosphere;Reflux;

Steps:

120

Reference Example 120 methyl 2-methyl-1,3-benzothiazole-7-carboxylate Under nitrogen atmosphere, a mixture of methyl 3-(ethanethioylamino)-2-iodobenzoate (6.00 g, 11.6 mmol) obtained in Reference Example 119, copper(I) iodide (0.110 g, 0.580 mmol), 1,10-phenanthroline (0.210 g, 1.16 mmol) and potassium t-butoxide (1.96 g, 17.5 mmol) in 1,2-dimethoxyethane (50 mL) was heated under reflux for 24 hr, and filtered through celite. The solvent was evaporated under reduced pressure. The residue was purified by silica gel column chromatography (ethyl acetate/hexane=1/2) to give the title compound (1.80 g, yield 75%). ¹H-NMR (CDCl₃) δ: 2.87 (3H, s), 4.02 (3H, s), 7.54 (1H, t, J = 7. 6 Hz), 8.09 (1H, dd, J = 7.6, 1.2 Hz), 8.14 (1H, dd, J = 8.0, 1.2 Hz).

References:

EP2141150,2010,A1 Location in patent:Page/Page column 105