Hydrochloric Acid → (E)-3-[2-cyclopropyl-4-(4-fluoro-phenyl)-quinolin-3-yl]-acrylic acid

Participants

Reaction Conditions

Reaction Steps

To a mixture of diisopropylamine (2.42 g, 24.0 mmol) and 8.88 ml (24.0 mmol) butyllithium (2.7M in Heptan) in THF (20 ml) at −70° C. is added a soln. of crotonic acid (1.03 g, 12.0 mmol) in THF (10.0 ml). After stirring at −70° C. and 0° C., a soln. of cyclopropanecarboxylic acid N,O-dimethylhydroxylamide (1.29 g, 10.0 mmol) in THF (10.0 ml) is added. The solution is heated to 48° C. After cooling to −50° C., a solution of glacial acetic acid (5 ml) in THF (10 ml), and 20% aq. NaCl (25 ml) are slowly added. The pH is adjusted to 1.5 with 2M HCl and the mixture is extracted with CH2Cl2 (3×25 ml). Organic phases are washed with 20% aqeous NaCl (2×25 ml) and evaporated to dryness under reduced pressure. The resulting yellow oil is dissolved in toluene (100 ml). 4-Fluoro-2′-aminobenzophenone methansulfonic acid salt (3.23 g, 10.4 mmol) is added and the solution is refluxed in a water separator apparatus for 24 h. Upon cooling, a brown precipitate is formed, which is separated from the mother liquor and purified by chromatography on silica gel (CH2Cl2—MeOH) to afford (E)-3-[2-cyclopropyl-4-(4-fluoro-phenyl)-quinolin-3-yl]-acrylic acid. MS (ES): [M−H]− 332.

Provenance & Evidence