3,5-Dichloro-1-fluoropyridinium triflate → 2-Cyano-7-fluoro-6-hydroxybenzothiazole

To a suspension of 2-cyano-6-hydroxybenzothiazole (2.0 g, 11.4 mmol) in dichloromethane (50 ml) in a 250-ml round-bottomed flask was added 3,5-dichloro-1-fluoropyridinium triflate (6.1 g, 19.3 mmol). The reaction flask was fitted with a reflux condenser and the mixture was brought to reflux under argon atmosphere for 53 hr. Additional 3,5-dichloro-1-fluoropydidinium toiflate was added (1.0 g, 3.2 mmol) and reaction continued for another 22 hr. Additional 3,5-dichloro-1-fluoropylidinium triflate was added (1.0 g, 3.2 mmol)and reaction continued for another 27 hr. Additional 3,5-dichloro-1-fluoropyridinium triflate was again added (1.0 g, 3.2 mmol) and reaction continued for another 72 hr. The reaction mixture was concentrated by rotoevaporation to give a brown residue that was purified by flash chromatography with 100 g of silica gel and methylene chloride as eluting solvent. The title compound was obtained as a white solid. Yield: 0.97 g (44%).

1. customThe reaction flask was fitted with a reflux condenser
2. temperatureto reflux under argon atmosphere for 53 hr
3. additionAdditional 3,5-dichloro-1-fluoropydidinium toiflate was added
4. custom(1.0 g, 3.2 mmol) and reaction
5. custom(1.0 g, 3.2 mmol)and reaction
6. waitcontinued for another 27 hr
7. custom(1.0 g, 3.2 mmol) and reaction
8. waitcontinued for another 72 hr
9. concentrationThe reaction mixture was concentrated by rotoevaporation
10. customto give a brown residue that
11. customwas purified by flash chromatography with 100 g of silica gel and methylene chloride
12. washas eluting solvent

ORD record

ord-062e81025a9f4791a380e273463180ec

Source dataset

uspto-grants-2000_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06140051