An improved regioselective synthesisof 6-chloro-1H-quinoxalin-2-one by using p-chloroaniline as a starting material was described. The synthetic steps involved condensation, nitration, reduction, cyclization, and oxidation reactions. The nitration using chloroacetic chloride as an amino protective reagent of phenylamine and reduction of nitro group accompanied by active chlorine were well studied. The result shows that the nitration reaction using chloroacetic chloride as amino protective reagentof phenylamine complies with the general rule of nitration and good selectivitycan be obtained by using iron powder as reductant in the reduction of nitro group accompanied by active chlorine.

Key words: quinoxalin-2-one, p-chloroaniline, regioselective synthesis