The invention relates to novel 2-oxo-1-oxa-8-azaspiro[4,5]decane derivatives of the formula (I), ##STR1## wherein X means oxygen or an >NR group, wherein R stands for hydrogen; a C.sub.1-12 alkyl; C.sub.3-6 cycloalkyl; carbocyclic C.sub.6-10 aryl or carbocyclic C.sub.6-10 aryl-C.sub.1-4 alkyl group, the two latter two substituents optionally substituted on their aromatic moiety by one or more, same or different halogen, one or more C.sub.1-4 alkyl, C.sub.1-4 alkoxy or trihalomethyl group; or a tosyl group; R.sup.1 and R.sup.2 together represent a methylene group or, when X stands for an >NR group wherein R is as defined above, one of R.sup.1 and R.sup.2 m may represent a hydroxyl group and the other one is a methyl group; and R.sup.3 means hydrogen, benzyl, (C.sub.1-4 alkoxy)carbonyl, phenoxycarbonyl, benzyloxycarbonyl, formyl, piperidin-1-ylcarbonyl, morpholin-4-ylcarbonyl, 4-methylpiperazin-1-ylcarbonyl, 4-(2-hydroxethyl)piperazin-1-ylcarbonyl, 2-chloro-3-nicotinoylcarbamoyl or C.sub.1-6 alkylcarbamoyl group, as well as their acid addition and quaternary ammonium salts.

The invention relates to novel, therapeutically active 4-methylene-2-oxo-8-azaspiro[4,5]decane derivatives of the compound, ##STR1## wherein X means oxygen or an >NR group, wherein R stands for hydrogen, C.sub.1-12 alkyl, C.sub.3-6 cycloalkyl, carbocyclic C.sub.6-10 aryl or carbocyclic C.sub.6-10 arylC.sub.1-4 alkyl group, the latter two being optionally substituted on their aromatic moiety by one or more, same or different halogen(s) or one or more C.sub.1-4 alkyl group(s) or by one or more C.sub.1-4 alkoxy group(s); R.sup.3 and R.sup.4, which are the same or different, represent hydrogen, one or more halogen(s), C.sub.1-4 alkyl, C.sub.1-4 alkoxy, trihalomethyl group or hydroxyl group optionally esterified by a C.sub.1-4 alkanoic acid; and is 1 or 2, their isomers, solvates, hydrates, acid addition and quaternary ammonium salts.

The invention relates to novel, therapeutically active 4,4-disubstituted piperidine derivatives of the formula (I), ##STR1## wherein R.sup.1 means hydrogen or --CONHR group, wherein R stands for hydrogen, C.sub.1-12 alkyl, C.sub.3-6 cycloalkyl, carbocyclic C.sub.6-10 aryl or carbocyclic C.sub.6-10 aryl-C.sub.1-4 alkyl group, the latter two being optionally substituted on their aromatic moiety by one or more, same or different halogen(s) or one of more C.sub.1-4 alkyl or C.sub.1-4 alkoxy group(s); R.sup.2 stands for an ethynyl or acetyl group; R.sup.3 and R.sup.4, which are the same or different, represent hydrogen, one or more halogen(s), C.sub.1-4 alkyl, C.sub.1-4 alkoxy, trihalomethyl group or hydroxyl group optionally esterified by a C.sub.1-4 alkanoic acid; and n is 1 or 2, as well as their pharmaceutically acceptable acid addition and quaternary ammonium salts.