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Scale-Up Procedure. 5-Formyl-2,4-dimethyl-1H-pyrrole-3-carboxylic acid (61 g), 5-fluoro-1,3-dihydro-indol-2-one (79 g), ethanol (300 mL) and pyrrolidine (32 mL) were refluxed for 4.5 hours. Acetic acid (24 mL) was added to the mixture and refluxing was continued for 30 minutes. The mixture was cooled to room temperature and the solids collected by vacuum filtration and washed twice with ethanol. The solids were stirred for 130 minutes in 40% acetone in water (400 mL) containing 12 N hydrochloric acid (6.5 mL). The solids were collected by vacuum filtration and washed twice with 40% acetone in water. The solids were dried under vacuum to give 5-[5-fluoro-2-oxo-1,2-dihydro-indol-(3Z)-ylidenemethyl]-2,4-dimethyl-1H-pyrrole-3-carboxylic acid (86 g, 79% yield) as an orange solid.

1. temperaturerefluxing
2. filtrationthe solids collected by vacuum filtration
3. washwashed twice with ethanol
4. additioncontaining 12 N hydrochloric acid (6.5 mL)
5. filtrationThe solids were collected by vacuum filtration
6. washwashed twice with 40% acetone in water
7. customThe solids were dried under vacuum