Diethyl Ether → 2,6-Dichlorobenzothiazole

2-Amino-6-chlorobenzothiazole (15.7 g, 85 mmol) in H3PO4 (85%) (470 mL) was heated to 100° C. and dissolved. Then clear solution was cooled and vigorously stirred by mechanical stirrer. NaNO2 (17.6 g, 255 mmol) in water (30 mL) was added slowly keeps the temperature below 0° C. Separately a solution of CuSO4/5H2O (85 g), NaCl (107 g) in water (350 mL) was cooled to −5° C. and stirred by mechanical stirrer. After potassium iodide starch paper's color was disappeared diazonium solution was keeping cold and added slowly to the copper chloride solution with vigorous stirring. The reaction mixture was allowed to warm to room temperature. After 1 h water (1 L) and ether (1 L) were added to the reaction mixture and extracted twice. Organic layer was washed by water and dried over anhydrous MgSO4 and concentrated. Crude residue was purified by silica gel chromatography (H/A=4/1, 180 g of silica gel) to provide title compound 101 (7.46 g, 48%).

1. dissolutiondissolved
2. temperatureThen clear solution was cooled
3. customthe temperature below 0° C
4. stirringstirred by mechanical stirrer
5. extractionextracted twice
6. washOrganic layer was washed by water
7. dry with materialdried over anhydrous MgSO4
8. concentrationconcentrated
9. customCrude residue was purified by silica gel chromatography (H/A=4/1, 180 g of silica gel)

ORD record

ord-07538ba08b2b4d42aa730419729c1c59

Source dataset

uspto-grants-2003_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06583157B2