PURPOSE: To provide a method for economically and safely preparing a highly pure enamine in high yield by condensing a cycloalkanone or a cycloalkanedione with aniline in an aqueous medium.
CONSTITUTION: (A) A compound of formula I [R is CN, CO2H, CO2R1 (R1 is a lower alkyl); X is H, a lower alkyl, a lower alkoxy, a halogen, hydroxy or the like] is condensed with (B) a compound of formula II [Y is CH2 or C=O; (n) is 0, 1 or 2] in the presence of an acidic promoter in an aqueous medium preferably by adding an auxiliary solvent such as ethanol and 2- propanol to provide a compound of formula III in the method for preparing an enamine. Memory enhancing 9-amino-1,2,3,4-tetrahydroacridine can be obtained by cyclizing the compound of the formula III.
JPH02167267A | 1990-06-27 |