Hydrochloric Acid → 6-Bromo-5',6'-dihydro-4'H-spiro[chromene-2,3'-pyran]-4(3H)-imine

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Reaction Steps

HCl (4 M in 1,4-dioxane) (0.395 mL, 12.99 mmol) was added to a suspension of N-(6-bromo-5′,6′-dihydro-4′H-spiro[chromene-2,3′-pyran]-4(3H)-ylidene)-2-methylpropane-2-sulfinamide (Example 45 Step 1, 520 mg, 1.30 mmol) in anhydrous 1,4-dioxane (6 mL) and the resulting mixture was stirred under a nitrogen atmosphere at r.t. for 2 days. A precipitate was formed. The precipitate was filtered off and washed with Et2O. The solid was then dissolved in DCM and sat. aq. NaHCO3. The mixture was poured into a phase separator, the organic layer was collected and concentrated. The title compound was used directly in the next step without any further purl fi cation.

Provenance & Evidence