Yield:166668-76-4 85%

Reaction Conditions:

with methanol in tetrahydrofuran at 0 - 20; for 0.166667 h;

Steps:

10-1 Methyl 4,5-dichloro-isothiazole-3-carboxylate

Production Example 10-1
Methyl 4,5-dichloro-isothiazole-3-carboxylate
To a mixed solution of 4,5-dichloroisothiazole-3-carboxylic acid(0.20 g, 1.0 mmol) in tetrohydrofuran (5.0 mL) and methanol (0.50 mL), trimethylsilyldiazomethane (0.76 mL, 1.5 mmol, a 2.0 M solution in tetrahydrofuran) was added dropwise at 0° C.
The resulting mixture was then stirred at room temperature for 10 minutes, and then a mixture of acetic acid and water (1:1) (0.18 mL) was added dropwise thereto at 0° C., and the reaction mixture was stirred for 30 minutes.
Water was added to the reaction mixture, and the resulting mixture was extracted with ethyl acetate.
The organic layer was washed with a saturated saline solution, and then dried over anhydrous magnesium sulfate.
The solvent was concentrated under reduced pressure, and then the residue was separated and purified by silica gel column chromatography (ethyl acetate:heptane=1:10) to obtain the title compound (0.18 g, 85% yield).
¹H-NMR Spectrum (400 MHz, CDCl₃) δ (ppm): 4.01 (s, 3H).

References:

US2016/168176,2016,A1 Location in patent:Paragraph 0270; 0271; 0272