Реакция #428357

Уравнение реакции

Methyl lithium

4-bromo-pyrazole-1-sulfonic acid dimethylamide

triethyl borate

→

gum

Выход 64.3%

1-Dimethylsulfamoyl-1H-pyrazole-4-boronic acid

Выход 64.3%

Растворители

THF

Условия реакции

Обработка

1. 1
   Другоеremained >-60° C
2. 2
   ДругоеThe reaction was quenched with 2N HCl (25 ml)
3. 3
   Экстракцияextracted with EtOAc (×3)
4. 4
   Сушкаdried (Na2SO4)
5. 5
   Фильтрацияfiltered
6. 6
   Другоеthe solvent removed in vacuo
7. 7
   ДругоеThe material was purified by silica column chromatography

Методика

Methyl lithium (1.6M in Et2O, 12.2 ml, 19.5 mmol) was added to a stirred solution of 4-bromo-pyrazole-1-sulfonic acid dimethylamide (3.18 g, 14.9 mmol) and triethyl borate (3.80 ml, 22.3 mmol) in anhydrous THF (40 ml), such that the internal temperature remained >-60° C. After 30 min, the reaction was allowed to warm to room temperature and stirred for 18 h. The reaction was quenched with 2N HCl (25 ml), then extracted with EtOAc (×3). The organic extracts were combined, dried (Na2SO4), filtered and the solvent removed in vacuo. The material was purified by silica column chromatography to afford a colourless gum (2.1 g). MS: [M+H]+=220

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