Triisopropyl borate → 3-{5-[2-Methoxy-5-(2-methoxy-ethoxy)-phenyl]-pyridin-2-yloxy}-azetidine-1-carboxylic acid pyridazin-3-ylamide

Participants

Reaction Steps

A solution of 2-bromo-1-methoxy-4-(2-methoxy-ethoxy)-benzene (110 mg, 0.42 mmol) in anhydrous THF (2 mL) was cooled to −78° C. with a CO2-acetone bath under a nitrogen atmosphere. Triisopropyl borate (0.19 mL, 0.842 mmol) was added, followed by n-butyl lithium solution (2.5M in hexanes, 0.22 mL, 0.55 mmol). The mixture was allowed to warm to ambient temperature the solvents were removed in vacuo to afford a colourless solid. To the crude boronic acid was added 3-(5-iodo-pyridin-2-yloxy)-azetidine-1-carboxylic acid pyridazin-3-ylamide (Example 7, step 1) (150 mg, 0.38 mmol), 1N aqueous sodium bicarbonate solution (1.26 mL), DMF (7 mL) and 1,1′-bis[(diphenylphosphino)-ferrocene]dichloropalladium(II) complex with CH2Cl2 (15 mg). Nitrogen gas bubbled through mix for 5 minutes and reaction mixture heated at 80° C. for 2 hr. Mix was allowed to cool, partitioned between ethyl acetate (30 mL) and water (30 mL). Organic phase was separated then washed with sat. aqueous sodium chloride solution (60 mL) and dried over sodium sulphate. Solvents were removed in vacuo to afford a crude oil which was purified by flash chromatography on silica gel, eluting with a gradient of 0-10% ethyl acetate in hexane to afford the title compound (77 mg, 41%) as a pale yellow foam.

Provenance & Evidence