Abstract
N-Oxides of pyridine, quinoline, and pyrazine derivatives were reduced with chromium (II) chloride in acetone, methanol, or chloroform at room temperature to give the deoxygenation products in excellent yields. Quinaldine and 2-ethoxyquinoline 1-oxides, possessing an electron donating group at 2-position of the quinoline ring, were not reduced at room temperature, but, under reflux, the reaction gave the deoxygenation products in good yields. In the case of the reaction of 4-chloroquinoline 1-oxide with chromium (II) chloride for 20 min occured dechlorination and deoxygenation, but for 1 min only deoxygenation. The reaction of 4-nitropyridine 1-oxide and 3-, 4-, and 5-nitroquinoline 1-oxides was not successful.
