NEW MATERIAL: A compd. of formula I [R1 and R2 are each H, alkyl, alkenyl, cocyloalkyl, etc., R1 and R2 together form polymethylene or alkenylene but are not simultaneously H; R3 is H, alkyl or phenyl, R3 and R1 together form (CH2)3 or (CH2)4; p is 1 to 4; R is formula II [(CHR4)nX is a meta or para position with respect to YR5 or R6; R4 is H or alkyl; n is 0 to 2; X is a direct bond, O, S, etc.; Y is =C=O, =CHOH, -S=O, etc.; R5 and R6 are each 1-6C alkyl, R5 and R6 are each a bond, etc.]], or its solvate or its salt.

EXAMPLE: 1-[1-Oxo-3,4-dihydro-(2H)-naphtho-6-yl]acetyl-2-(pyrolidine-1-yl)methyl- pepridine.

USE: An analogesic.

PROCESS: A compd. of formula Ia of the compd. of the formula I is obtd. by bringing, for example, a compd. of formula III (R1' and R2' are each R1', R2', etc.), and a compd. of formula IV (R' is R1, etc.), into reaction.