N-methyl-2-oxoindoline-5-sulfonamide → 2-Methyl-6-[5-methylsulfamoyl-2-oxo-1,2-dihydro-indol-(3Z)-ylidene]-1,4,5,6-tetrahydro-cyclopenta[b]pyrrole-3-carboxylic acid

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Reaction Conditions

Reaction Steps

A mixture of 2-oxo-2,3-dihydro-1H-indole-5-sulfonic acid methylamide (905 mg, 4 mmol) and 2-methyl-6-oxo-1,4,5,6-tetrahydro-cyclopenta[b]pyrrole-3-carboxylic acid (Example B, 716 mg, 4 mmol) in DMF (50 mL) and piperidine (5 mL) was heated at 110° C. with stirring for 48 hours. The solvent was removed and the residue was suspended in methanol-ice-water and acidified with 2N HCl. The solid was collected by filtration and then suspended in DCM. The suspension was washed with 2N aq. NaOH for three times. The combined water layer was backwashed with DCM. The water layer was acidified with 2N HCl and filtered to give a brown solid, which was triturated with MeOH to afford 380 mg of the titled compound as a brown yellow solid. The combined organic layer was dried (Na2SO4) and evaporated to give 130 mg of 3-[2-methyl-4,5-dihydro-1H-cyclopenta[b]pyrrol-(6Z)-ylidene]-2-oxo-2,3-dihydro-1H-indole-5-sulfonic acid methylamide (Example 4) as a yellow solid.

Provenance & Evidence