2(1H)-Quinoxalinone → 2-Chloroquinoxaline

Quinoxalin-2-one (14.62 g, 100 mmol) was added to POCl3 (100 g, 0.65 mmol) and the mixture heated at reflux for 1.5 hours under N2. Upon cooling, the mixture was poured slowly, portionwise onto 700 ml of H2O. The black solution was extracted with CH2Cl2 (2×250 ml). The combined CH2Cl2 portions were washed with H2O, dried over Na2SO4, filtered, and evaporated to give a brown, solid 2-chloroquinoxaline. A portion of said product (4.00 g, 24.3 mmol) was combined with 5 ml of 1 N HCl, and NaN3 (1.89 g, 29.1 mmol) in 220 ml of abs EtOH and heated at reflux for 7 hours. The mixture was allowed to cool overnight, which led to precipitation of yellow-brown needles of tetrazolo[1,5-a]quinoxaline (19).

1. temperaturethe mixture heated
2. temperatureat reflux for 1.5 hours under N2
3. temperatureUpon cooling
4. extractionThe black solution was extracted with CH2Cl2 (2×250 ml)
5. washThe combined CH2Cl2 portions were washed with H2O
6. dry with materialdried over Na2SO4
7. filtrationfiltered
8. customevaporated

ORD record

ord-37c25d6ef84541e38e4db3e59a32c4d6

Source dataset

uspto-grants-1992_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05153196