Hydrochloric Acid → 6-Oxo-(3-quinolin-3-yl)-9-(5,6,7,8-tetrahydro-[1,8]naphthyridin-2-yl)-nonanoic acid

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Reaction Steps

Ketophosphonate 22-5 (1.0 g, 3.1 mmol), anhydrous LiCl (170 mg, 4.0 mmol), and 22-4 (0.797 g, 3.1 mmol) in anhydrous acetonitrile (60 mL), was treated with DBU (0.52 mL, 3.3 mmol) and the resulting suspension stirred at room temperature for 1 h. The solvent was removed at reduced pressure and the resulting residue partitioned between brine and methylene chloride. The organic layer was removed, dried, and concentrated to afford 22-6 as mixture of E and Z olefins. The crude mixture was dissolved in EtOH (50 mL), treated with 10% Pd/C (200 mg) and stirred under a hydrogen filled balloon for 4 h, then filtered. The filtrate was treated with LiOH (2.0 eq) and water (20 mL) and stirred at room temperature for 12 h, then neutralized with 1N HCl and evaporated Chromatography on silica gel (10% MeOH/methylene chloride) afforded 22-7 as a white solid.

Provenance & Evidence