Triphenylphosphine → 4-{1-[3-(2,6-Dichloro-phenyl)-5-isopropyl-isoxazol-4-ylmethyl]-6-oxo-1,6-dihydro-pyridazin-3-yloxy}-benzoic acid methyl ester

Participants

Reaction Steps

To a mixture of 4-(6-oxo-1,6-dihydro-pyridazin-3-yloxy)-benzoic acid methyl ester (0.43 g, 1.75 mmol), [3-(2,6-dichloro-phenyl)-5-isopropyl-isoxazol-4-yl]-methanol (0.50 g, 1.75 mmol) and triphenylphosphine (0.56 g, 2.1 mmol) in benzene (12 ml) was added dropwise 0.6 ml (2.9 mmol) of diisopropyl 1,2-diazenedicarboxylate (DIAD). The reaction mixture was stirred at room temperature for 27 h and the solvent was removed in vacuo. The residue was subjected to preparative HPLC purification eluting with acetonitrile/water 1:1 to provide 0.08 g (9%) of the desired 4-{6-[3-(2,6-dichloro-phenyl)-5-isopropyl-isoxazol-4-ylmethoxy]-pyridazin-3-yloxy}-benzoic acid methyl ester together with 0.52 g (58%) of 4-{1-[3-(2,6-dichloro-phenyl)-5-isopropyl-isoxazol-4-ylmethyl]-6-oxo-1,6-dihydro-pyridazin-3-yloxy}-benzoic acid methyl ester.

Provenance & Evidence