Tricyclo piperidino ketones and soporific compositions thereof

A compound of the formula, ##STR13## wherein n is 1, 2 or 3,

• R.sub.1 is lower alkyl,
• R.sub.2 is hydrogen or lower alkyl,
• R.sub.3 is hydrogen, chlorine, bromine, fluorine, trifluoromethyl, lower alkyl, lower alkoxy or lower alkylthio,
• A and B together with the double bond form a benzene ring, or a benzene ring substituted by chlorine, bromine, fluorine, trifluoromethyl, lower alkyl, lower alkoxy or lower alkylthio, or
• A is sulphur and
• A and B together with the double bond form a thiophene ring, or a thiophene ring substituted in the .alpha. position to the sulphur by chlorine, bromine or lower alkyl, and
• Y is ethylene or vinylene, when A and B together with the double bond form a benzene ring, or a benzene ring substituted by chlorine, bromine, fluorine, trifluoromethyl, lower alkyl, lower alkoxy or lower alkylthio, or when A is sulphur and A and B together with the double bond form a thiophene ring, or a thiophene ring substituted in the .alpha. position to the sulphur by chlorine, bromine or lower alkyl, or
• Y is oxygen, methyleneoxy, methylenethio or a group ##STR14## wherein R.sub.4 and R.sub.5 are independently lower alkyl, when A and B together with the double bond form a benzene ring, or a benzene ring substituted by chlorine, bromine, fluorine, trifluoromethyl, lower alkyl, lower alkoxy or lower alkylthio, or
• Y is sulphur, when A is sulphur and A and B together with the double bond form a thiophene ring,
• or a pharmaceutically acceptable acid addition salt thereof.