Triphenylphosphine → Methyl 3-{3-[5-(3-dimethylaminopropoxy)pyrimidin-2-yl]-benzyl}-2-oxo-2,3-dihydrobenzoxazole-5-carboxylate

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Reaction Steps

1.84 g (9.5 mmol) of methyl 2-oxo-2,3-dihydrobenzoxazole-5-carboxylate and 4.75 g (14.25 mmol) of polymer-bound triphenylphosphine (3 mmol/g) are added to a solution of 3.03 g (10.45 mmol) of {3-[5-(3-dimethylaminopropoxy)pyrimidin-2-yl]phenyl}methanol in 40 ml of THF. The suspension is shaken at room temperature for 30 min. The suspension is cooled in an ice bath, and 3.35 g (14.25 mmol) of di-tert-butyl-azodicarboxylate are added in portions. After the mixture has been stirred at room temperature for 24 h, a further 4.75 g (14.25 mmol) of polymer-bound triphenylphosphine (3 mmol/g) and 3.35 g (14.25 mmol) of di-tert-butyl azodicarboxylate are added, and the mixture is shaken at room temperature for a further 24 h. The reaction mixture is filtered, the filtrate is evaporated to dryness, and the residue is purified by column chromatography on silica gel, giving 947 mg of “A64”; m.p. 125° C., ESI: 463 (M+H); Rt=3.07 min (method C);

Provenance & Evidence