| Abstract: | The reaction of 4-aryl-2-hydrazino-3-nitro-6-R-quinolines with NaNO2 in AcOH gives the corresponding tetrazolo1,5-a]quinolines. In contrast to tetrazolo1,5-c]pyrimidines they cannot be converted to 6-R-4-phenyl1,2,5]oxadiazolo3,4-b]quinoline-3-oxides by heating in THF, toluene, or AcOH. Total energy quantum-chemical calculations using the MINDO/3 and MNDO methods show that 1,2,5]oxadiazolo3,4-b]quinoline-3-oxides are significantly higher in energy (230-280 kcal/mol) than the mentioned tetrazolo1,5-a]quinolines and hence their formation is unlikely. |
