Abstract: An indolone derivative is useful for the treatment of anxiety, depression and schizophrenia and is a 5HT.sub.1A agonist and 5HT.sub.2 antagonist, which is a compound of formula (I): ##STR1## in which R.sub.1 is a hydrogen or halogen atom or a (C.sub.1-4)alkyl radical,R.sub.2 is a hydrogen atom or a (C.sub.1-4)alkyl radical,R.sub.3 is a hydrogen atom, a (C.sub.1-4)alkyl radical or an S-(C.sub.1-4) alkyl radical; andR.sub.4 is a phenyl, chlorophenyl, naphthyl, 7-methoxy-1-naphthyl, 6-methoxy-1-indanyl, 2-methoxy-6-pyridyl, 3-methoxy-2-pyridyl, isoquinolyl, 7-methoxy-1-isoquinolyl, 7-methoxy-1,2,3,4-tetrahydro-1-naphthyl or 7-fluoro-1-naphthyl radical;or a pharmaceutically acceptable acid addition salt thereof.

Abstract: A piperazine derivative of formula (I) ##STR1## in which: R is hydrogen or a straight or branched (C.sub.1 -.sub.4) alkoxycarbonyl group; andA is a 7-methoxy-1-naphthalenyl, 6-methoxy-2,3-dihydro-1-(1H)-indenyl or 7-methoxy-1,2,3,4-tetrahydro-1-naphthalenyl group, or an optically active isomer thereof, or a salt thereof.

Abstract: A compound which is a piperidine derivative of formula (I) ##STR1## in which: n is 1, 2, 3 or 4,R is hydrogen or a halogen,R', which is identical to R, is hydrogen or a halogen,either R.sub.1 is H or OH and R.sub.2 is H, or R.sub.1 and R.sub.2 together denote a bond,R.sub.3 is hydrogen or (C.sub.1-4) alkyl, andR.sub.4 is H or OH,including tautomeric forms thereof, or a pharmaceutically acceptable acid addition salt thereof.

Abstract: Imidazo[4,5-b]pyridin-2-one derivatives of the formula (I) ##STR1## in which n is 2, 3 or 4, x is .dbd.CH-- or .dbd.N--, R.sub.1 and R.sub.2, which may be the same or different, each represent hydrogen, halogen or (C.sub.1-4) alkoxy and either R.sub.3 is H or OH and R.sub.4 is H, or R.sub.3 and R.sub.4 together form a direct bond, their enantiomers and their addition salts with pharmaceutically acceptable acids are pharmacologically active, for example as antagonists to histamine and serotonin.

Abstract: Piperidine derivatives which are compounds of formula (I) ##STR1## wherein Ar.sub.1 and Ar.sub.2 independently represent a phenyl group optionally substituted by a halogen atom, a thienyl group or a pyridinyl group, A represents an alkylene group of 2 to 6 carbon atoms, X represents a CO group or a bond, R.sub.1 represents a hydrogen atom or an alkyl group of 1 to 4 carbon atoms, either R.sub.2 represents a hydrogen atom and R.sub.3 represents a hydrogen atom or a hydroxy group, or R.sub.2 and R.sub.3 together represent a bond, and R.sub.4 represents a hydrogen or halogen atom, or pharmaceutically acceptable acid addition salts thereof are useful as antiallergics and antipruritics.