Ethyl orthoformate → 6-Bromo-8-chloro[1,2,4]triazolo[4,3-a]pyrazine

Temperature

130 °C

A 50 mL round bottom flask was charged with 5-bromo-3-chloro-2-hydrazinylpyrazine (1.24 g, 5.5 mmol) and triethyl orthoformate (20 mL). The resulting mixture was stirred at 130° C. for 2 h. Reaction progress was monitored by TLC (EtOAc/petroleum ether=1:2). Work-up: the reaction mixture was diluted with water and extracted with EtOAc (50 mL×3). The combined organic layers were dried over anhydrous Na2SO4 and concentrated in vacuo. The residue was further purified by flash column chromatography on silica gel with 30% EtOAc in petroleum ether, to afford 1.12 g (87%) of the product as a red solid.

1. customReaction progress
2. extractionextracted with EtOAc (50 mL×3)
3. dry with materialThe combined organic layers were dried over anhydrous Na2SO4
4. concentrationconcentrated in vacuo
5. customThe residue was further purified by flash column chromatography on silica gel with 30% EtOAc in petroleum ether

ORD record

ord-f117d7fb853541d5abcca5fa78a22508

Source dataset

uspto-grants-2013_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08569300B2