Crude (E)-(R)-3-(tert-Butyl-dimethyl-silanyloxy)-7-[2-cyclopropyl-4-(4-fluoro-phenyl)-quinolin-3-yl]-5-oxo-hept-6-enoic acid ((S)-1-phenyl-ethyl)-amide (655.1 g) from example c) is placed in a 4-necked, round bottomed flask, equipped with a mechanical stirrer, digital thermometer, nitrogen inlet-outlet and a condenser. Ethanol (2400 mL) is added to obtain a solution. The solution is cooled to 0-4° C. and hydrochloric acid (2M aqueous solution, 657.1 g, 1276 mmol) is added dropwise at this temperature. The reaction mixture is warmed up to 25° C. and stirred at this temperature for additional 4 hours for completion of the deprotection. The reaction mixture is then poured onto an aqueous solution of sodium bicarbonate (7400 mL of a 2% solution) and extracted with ethyl acetate (5000 mL). The organic layer is washed with brine (1800 mL), the water layers are combined and extracted with ethyl acetate (2000 mL). The organic layers are combined, dried over magnesium sulfate and the solvent is evaporated in vacuo to obtain 561.2 g of a braun, honey-like crude product. The crude product is dissolved in toluene (860 mL) and n-hexane (1075 mL) is added. The mixture is heated at 60° C. for 2 hours and at 50° C. for 1 hour. n-Hexane (1075 mL) is added at 50° C. and the suspension is allowed to cool down to room temperature. Stirring is continued over night at room temperature and for additional 3 hours at 0° C. The solid product is isolated by filtration, the filter cake is washed with ice-cold n-hexane (502 mL) and dried in vacuo to obtain (E)-(R)-7-[2-cyclopropyl-4-(4-fluoro-phenyl)-quinolin-3-yl]-3-hydroxy-5-oxo-hept-6-enoic acid ((S)-1-phenyl-ethyl)-amide as a yellow powder.
