PURPOSE: A β-lactam is hydrogenolyzed in the presence of a palladium catalyst to produce the title compound used as a remedy for Partkinson's diseases from an inexpensive starting material through shortened process in high yield.
CONSTITUTION: In the presence of a palladium catalyst, the hydrogenolysis of a β- lactam of formula I (R1, R2 are H, alkyl, benzyl, acyl and they may incorporate to form alkylene; R3 is alkyl, aryl, aromatic heterocycle; X is amino, azide) is effected to produce a dopa derivative of formula II. As the palladium catalyst, Pd-C is preferred, because the palladium metal is well dispersed and it is high effective even in a small amount and the amount is usually 1W50% based on the β-lactam (calculated as palladium metal). The reaction pressure is preferably 1W20 atmospheric one, because it is easy-to-operate.
SUGA SHIGEI
ABE RUMIKO
