Reaktion #69535

Reaktionsgleichung

7-[(tert-butoxycarbonyl)amino]-6-methyl-2-(methylthio)pyrazolo[5,1-b][1,3]thiazole-3-carboxylic acid

potassium hydroxide

bromine

→

title compound

Ausbeute 47.2%

tert-Butyl[3-bromo-6-methyl-2-(methylthio)pyrazolo[5,1-b][1,3]thiazol-7-yl]carbamate

Ausbeute 47.2%

Lösungsmittel

chloroform

Reaktionsbedingungen

Aufarbeitung

1. 1
   FiltrationThe solid was filtered
2. 2
   Waschenwashed with water
3. 3
   Sonstigedried
4. 4
   workup.ADDITIONTo a mixture of the obtained solid and carbon tetrachloride (3.6 mL)
5. 5
   workup.STIRRINGthe mixture was stirred at 75° C. for five hours
6. 6
   Filtrationthe insoluble matters were filtered off
7. 7
   workup.DISTILLATIONthe solvent was distilled off under reduced pressure
8. 8
   SonstigeThe residue was purified by medium pressure silica gel column chromatography (n-heptane/ethyl acetate

Vorschrift

To an aqueous solution (10 mL) of 7-[(tert-butoxycarbonyl)amino]-6-methyl-2-(methylthio)pyrazolo[5,1-b][1,3]thiazole-3-carboxylic acid (180 mg, 0.53 mmol), were added potassium hydroxide (34.7 mg, 0.53 mmol) and silver carbonate (93.6 mg, 0.55 mmol), and the mixture was stirred at room temperature for 1.5 hours. The solid was filtered, washed with water, and then dried. To a mixture of the obtained solid and carbon tetrachloride (3.6 mL) was added bromine (29.6 μL, 0.58 mmol), and the mixture was stirred at 75° C. for five hours. To the reaction mixture was added chloroform, and the insoluble matters were filtered off, and then the solvent was distilled off under reduced pressure. The residue was purified by medium pressure silica gel column chromatography (n-heptane/ethyl acetate: 33% then 66%) to obtain 94.0 mg (0.25 mmol) of the title compound.

Quelle