Thermolysis of several p-substituted arylazides (p-R-C6H4N3; R=COCH3, CO2CH3, COPh) in methanol gave 5-substituted 2-methoxy-3H-azepines in moderate yields. Thermolysis of m-substituted arylazides (m-R-C6H4N3; R=COCH3, CO2CH3, COPh, NO2) gave 4-substituted 2-methoxy-3H-azepines and 6-substituted 2-methoxy-3H-azepines in good yields. In contrast, thermolysis of p-azidoacetophenone in piperidine gave