The keto and enolic characters of 2, 6-dinitrocyclohexanone (1), 2, 6-dinitro-4- methylcyclohexanone (2), and 2, 7-dinitrocycloheptanone (3) were spectroscopically investigated and discussed. It was found that the reactions of 1 and 2 with nucleophiles can take either of two courses, depending upon the nucleophiles used:(a) the addition to the enol carbon or carbonyl carbon of the keto form, followed by ring-opening giving 2, 6- ...