2-Bromo-4-fluorobenzene-1-sulfonyl chloride → methyl 7-(2-bromo-4-fluorobenzenesulfonylamino]-2,3,9,9a-tetrahydro-1H-pyrrolo[1,2-a]indole-8-carboxylate

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Reaction Steps

A mixture of methyl 7-amino-2,3,9,9a-tetrahydro-1H-pyrrolo[1,2-a]indole-8-carboxylate (Intermediate 29, 0.400 g) and 2-bromo-4-fluorobenzenesulfonyl chloride (0.565 g) in pyridine (4 mL) and DCM (12 mL) was stirred at room temperature for 30 minutes. The mixture was diluted with ethyl acetate and washed with aqueous potassium carbonate solution (10%) and brine, dried (MgSO4) and filtered. The filtrate was concentrated in vacuo and the residue was purified by chromatography on silica, eluting with a mixture of methanol and DCM, with a gradient of 0-2%. The resultant solid was re-purified by chromatography on silica, eluting with a mixture of ethyl acetate and cyclohexane, containing 1% triethylamine, with a gradient of 0-100% to give a yellow solid which was again purified by chromatography on silica, eluting with a mixture of DCM and cyclohexane (50%), followed by DCM (100%). The resultant solid was purified by chromatography on silica, eluting with a mixture of ethyl acetate and cyclohexane, with a gradient of 5-30%, to give methyl 7-(2-bromo-4-fluorobenzenesulfonylamino]-2,3,9,9a-tetrahydro-1H-pyrrolo[1,2-a]indole-8-carboxylate (0.317 g) as a yellow gum.

Provenance & Evidence