Triphenylphosphine → 4-[2-(2-tert-Butyl-5-methyl-oxazol-4-yl)-ethoxy]-benzo[b]thiophene-7-carbaldehyde

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Reaction Steps

0.800 g of the above prepared (example 1, step f]) 2-(2-tert-butyl-5-methyl-oxazol-4-yl)-ethanol (4.37 mmol) was dissolved in 25 ml of toluene and treated successively at 0° C. with 0.778 g of 4-hydroxy-benzo[b]thiophene-7-carbaldehyde (4.37 mmol), 1.145 g of triphenylphosphine (4.37 mmol), and 0.883 g (4.37 mmol) of DIAD. The cooling bath was then removed and stirring continued for 4 h. Pouring onto crashed ice, twofold extraction with EtOEt, washing with dil. NaOH and water, drying over sodium sulfate, and evaporation of the solvents, followed by flash chromatography (SiO2, hexane/AcOEt=6/4) and crystallization from EtOEt, produced finally 0.713 g of the title compound as off-white crystals of mp. 140–42° (dec.).

Provenance & Evidence