| abstract |
NEW MATERIAL:A compound expressed by formula I (A ring represents piperidine ring which N atom may be substituted with a lower alkyl, etc., provided that the N atom of the piperidine ring and any carbon atom without a spiro-bonding may form a crosslinkage through a lower alkylene; X represents O or S; Y represents carbonyl, thiocarbonyl, etc.; R 1 to R 3 represent H or lower alkyl; R 4 represents H, lower alky, carboxy, lower alkoxycarbonyl or lower alkanoyl). n EXAMPLE: Ethyl 2,8-dimethyl-3-oxo-1-oxa-S-azaspiro[4,5]dicane-4-carboxylate. n USE: A prophylactic or remedy for diseases caused by nervous degeneration. n PREPARATION: A hetero-ring-ylidene acetic acid ester expressed by formula II [A' ring represents (substituted) piperidine ring; R 8 represents lower alkyl] is reacted with a hydroxy (or mercapto) carboxylic acid (or thiocarboxylic acid) ester expressed by formula III (Z 3 and Z 4 represent O or S). n COPYRIGHT: (C)1990,JPO&Japio |