To a suspension of 4-amino-5,7-dichloro-2-methoxycarbonyl-1,2,3,4-tetrahydroquinoline hydrochloride (example 9a) (3.0 g, 9.63 mmol) in anhydrous tetrahydrofuran (300 ml) under an atmosphere of nitrogen was added dry triethylamine (2.95 ml, 21.2 mmol) and the resulting mixture was stirred at room temperature for 0.5 h. To this suspension was added phenlyacetic acid (1.44 g, 10.6 mmol), 1-hydroxybenzotriazole (1.43 g, 10.6 mmol) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (2.03 g, 10.6 mmol) and stirring was continued for 65 h. The reaction mixture was concentrated in vacuo and the residue obtained was partitioned between ethyl acetate (1000 ml) and 1M aqueous citric acid (300 ml). The organic layer was collected, washed successively with 1M aqueous citric acid (1×300 ml), saturated sodium bicarbonate solution (2×300 ml) and brine (200 ml) then dried (MgSO4) and evaporated. The resulting crude product was recrystallised from methanol to give the title compound as colourless needles (2 crops, 3.26 g) identical in physical properties to the material obtained in example 34 step a.
