Реакция #2013602

Уравнение реакции

2-amino-4,5-difluoro-1,3-benzothiazole

HCl

NaNO2

HCl

→

title compound

2-Chloro-4,5-difluoro-1,3-benzothiazole

Условия реакции

Обработка

1. 1
   workup.STIRRINGstirring
2. 2
   workup.WAITwas continued at ambient temp. for 30 min
3. 3
   ЭкстракцияThe reaction mixture was extracted with diethyl ether (3×30 mL)
4. 4
   ПромывкаThe combined organic layers were washed with water (10 mL), dilute ammonium hydroxide (10 mL), brine (20 ml)
5. 5
   Сушкаdried over anhydrous Na2SO4
6. 6
   Фильтрацияfiltered
7. 7
   Концентрированиеconcentrated under reduced pressure
8. 8
   ДругоеThe residue was purified by column chromatography on silica gel (eluted by 2% methanol in methylene chloride)

Методика

To a mixture of 2-amino-4,5-difluoro-1,3-benzothiazole (130 mg, 0.70 mmol) and CuSO4 (20 mg) in conc. HCl (20 mL) was added NaNO2 (96 mg, 1.4 mmol, 2 eq, dissolved in 5 mL of water) dropwise at −10° C. over about 15 min. The reaction mixture was stirred for 1 h, poured into a solution of CuCl (67 mg, 0.7 mmol, 1 eq.) in conc. HCl (20 mL), and stirring was continued at ambient temp. for 30 min. The reaction mixture was extracted with diethyl ether (3×30 mL). The combined organic layers were washed with water (10 mL), dilute ammonium hydroxide (10 mL), brine (20 ml), dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure. The residue was purified by column chromatography on silica gel (eluted by 2% methanol in methylene chloride) to afford the title compound. 1H-NMR (CDCl3, 300 MHz): δ=7.20-7.15 (m, 1H), 7.13-7.04 (m, 1H).

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