Dimethyl Sulfoxide → 8-Bromo-4,5-dihydro-6-oxa-3-thia-1-aza-benzo[e]azulene-2-carbaldehyde

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Reaction Steps

Oxalyl chloride (0.24 mL, 2.9 mmol) was added dropwise to a solution of methyl sulfoxide (0.20 mL, 2.9 mmol) in dry dichloromethane (5 mL) and the resulting mixture was stirred 5 min. A solution of (8-Bromo-4,5-dihydro-6-oxa-3-thia-1-aza-benzo[e]azulen-2-yl)-methanol (0.60 g, 1.9 mmol) in dichloromethane (5 mL) was added portion-wise to the mixture and followed immediately by triethylamine (0.8 mL, 5.8 mmol). The reaction mixture was stirred and monitored by the disappearance of the starting alcohol. The reaction was quenched by the addition of water and EtOAc. The aqueous layer was extracted with EtOAc, dried over MgSO4, filtered and concentrated in vacuo. The residue was purified by ISCO chromatography (0-50% EtOAc/heptane) to provide 8-Bromo-4,5-dihydro-6-oxa-3-thia-1-aza-benzo[e]azulene-2-carbaldehyde (0.41 g, 69% yield). 1H NMR (400 MHz, CDCl3) δ 9.97 (s, 1H), 8.39 (dd, J=8.5, 6.8, 1H), 7.37-7.15 (m, 2H), 4.38 (m, 2H), 4.12 (d, J=9.5, 1H)

Provenance & Evidence