Tributylphosphine → methyl 3-{4-[(4-{[(4-formyl-1-phenyl-1H-pyrazol-3-yl)oxy]methyl}phenoxy)methyl]-5-methyl-1,3-oxazol-2-yl}benzoate

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Reaction Steps

To a mixture of methyl 3-(4-{[4-(hydroxymethyl)phenoxy]methyl}-5-methyl-1,3-oxazol-2-yl)benzoate (1.34 g), 3-hydroxy-1-phenyl-1H-pyrazole-4-carbaldehyde (0.50 g), tributylphosphine (0.77 g) and tetrahydrofuran (100 mL) was added 1,1′-(azodicarbonyl)dipiperidine (0.96 g) was added at room temperature, and the mixture was stirred for 15 hrs. The precipitated crystals were removed by filtration and the filtrate was concentrated. The residue was subjected to silica gel column chromatography to give methyl 3-{4-[(4-{[(4-formyl-1-phenyl-1H-pyrazol-3-yl)oxy]methyl}phenoxy)methyl]-5-methyl-1,3-oxazol-2-yl}benzoate as crystals (0.62 g, yield 47%) from a fraction eluted with ethyl acetate-hexane (1:2, v/v). Recrystallization from ethyl acetate-hexane gave colorless prism crystals. melting point: 161-162° C.

Provenance & Evidence