p-Toluenesulfonic acid monohydrate → (S)-methyl 2-(4-bromo-8-oxo-6,7,8,10-tetrahydro-3H-oxepino[3,4-e]indazol-7-yl)acetate

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Reaction Steps

(S)-Dimethyl 2-((3,7-dibromo-4-(hydroxymethyl)-1H-indazol-5-yl)methyl)succinate (440 mg, 1.065 mmol) was dissolved in toluene (30 mL). p-Toluenesulfonic acid monohydrate (28 mg, 0.147 mmol) was added to the mixture. Reaction was warmed to reflux and held for 18 hours with stirring. Mixture was cooled to room temperature and then diluted with ethyl acetate. Material was washed with aqueous sodium bicarbonate and the aqueous phase was discarded. Organics were dried MgSO4, filtered and then concentrated to dryness. Silica gel chromatography eluting ethyl acetate-hexanes afforded the title compound as amber oil in 42% yield. MS (M+H)+=367.2, 369.2.

Provenance & Evidence