Potassium Carbonate → 8-Bromo-2-ethynyl-4,5-dihydro-6-oxa-3-thia-1-aza-benzo[e]azulene

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Reaction Steps

8-Bromo-4,5-dihydro-6-oxa-3-thia-1-aza-benzo[e]azulene-2-carbaldehyde (0.688 g, 2.2 mmol) was dissolved in methanol (8 mL) and methyl 2-diazo-2-(dimethoxyphosphoryl)acetate (0.923 g, 4.44 mmol) was added followed by potassium carbonate (0.613 g, 4.44 mmol). The resulting mixture was stirred 12 h at ambient temperature and quenched by the addition of sat. NH4Cl aqueous solution and stirred 5 min. Diluted with H2O and EtOAc, extracted the aqueous layer with EtOAc (2×) and the combined organic portions were washed with brine. Dried over MgSO4, filtered and concentrated in vacuo. The residue was purified by ISCO chromatography (24 g column, 0-25% EtOAc/heptane) to provide 8-Bromo-2-ethynyl-4,5-dihydro-6-oxa-3-thia-1-aza-benzo[e]azulene as an oil (0.26 g, 38% yield). 1H NMR (400 MHz, CDCl3) δ 8.35 (d, J=8.5, 1H), 7.31-7.18 (m, 2H), 4.37 (t, J=5.1, 2H), 3.49 (s, 1H), 3.33 (t, J=5.1, 2H)

Provenance & Evidence