Diethyl Ether → 2,6-Dichlorobenzothiazole

2-Amino-6-chlorobenzothiazole (15.7 g, 85 mmol) in H3PO4 (85%) (470 ml) was heated to 100 degrees 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 degrees. Separately a solution of CuSO4/5H2O (85 g), NaCl (107 g) in water (350 ml) was cooled to −5 degrees 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-hour 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 363 (7.46 g, 48%).

1. dissolutiondissolved
2. temperatureThen clear solution was cooled
3. customthe temperature below 0 degrees
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-cd46554064794e8084bc0cd5db4caf1e

Source dataset

uspto-grants-2009_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07626033B2