反应详情

2-Hydroxyethyl 6-bromo-1-ethyl-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carboxylate (Intermediate 23, 100 mg, 0.29 mol), dibenzyl hydrogen phosphate (65 mg, 0.23 mmol) and triphenylphosphine (192 mg, 0.733 mmol) were dissolved in tetrahydrofuran (15 mL). Diisopropyl azodicarboxylate [DIAD] (106 mg, 0.52 mmol) was added drop wise and the mixture was stirred for 4 h at room temperature. The reaction mixture was concentrated under reduced pressure and water (100 mL) was added. The aqueous mixture was extracted with ethyl acetate (2×100 mL) and the combined organic layers were dried over anhydrous sodium sulphate, filtered and concentrated under reduced pressure to give a crude compound. The crude compound was purified by flash column chromatography over silica gel (10-50% ethyl acetate/petroleum ether) to afford 60 mg (40%) of 2-{[bis(benzyloxy)phosphoryl]oxy}ethyl 6-bromo-1-ethyl-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carboxylate.

1. concentrationThe reaction mixture was concentrated under reduced pressure and water (100 mL)
2. additionwas added
3. extractionThe aqueous mixture was extracted with ethyl acetate (2×100 mL)
4. dry with materialthe combined organic layers were dried over anhydrous sodium sulphate
5. filtrationfiltered
6. concentrationconcentrated under reduced pressure
7. customto give a crude compound
8. customThe crude compound was purified by flash column chromatography over silica gel (10-50% ethyl acetate/petroleum ether)