N-ethoxycarbonyl-p-chloroanilinoacetaldehyde diethyl acetal (3.0 g) and 3,4-dihydroxyphenethylamine hydrochloride (1.5 g) were added to a mixture of n-butyl alcohol (30 ml), water (5 ml) and 10% hydrochloric acid (0.5 ml), and then the mixture was refluxed for 4 hours in a stream of nitrogen. Above mentioned acetal (0.8 g) was further added to the mixture and the resultant mixture was refluxed for 4 hours. The solvent was distilled off from the reaction mixture and the residue was washed with ethyl acetate and then recrystallized from water to give 1-(N-ethoxycarbonyl-p-chloroanilinomethyl)-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline hydrochloride, mp 208° to 210° C. and mp 214° to 215° C. Analysis: Calcd. for C19H21N2O4Cl.HCl.3/10H2O: C 54.50, H 5.44, N 6.69, Cl 16.93. Measured: C 54.29, H 5.57, N 6.70, Cl 16.69.
