Hydrochloric Acid → HCID 12112198, compound

Participants

Reaction Conditions

Reaction Steps

To hydroxy(1-acetyl-4,6-dimethylindolin-5-yl)acetic acid (3.0 g) obtained in Example 1 and 7.5% palladium on charcoal (1.3 g, wet (water content: 53.1%)) placed in a 100-ml autoclave was added a saturated solution of hydrogen chloride in ethanol (30 ml). After degassing with nitrogen for 3 times (5 kg/cm2 for each) and replacing nitrogen with hydrogen for 3 times (5 kg/cm2 for each) successively, the resulting mixture was stirred for 5 hours at 70° C. under a pressurized hydrogen atmosphere (5 kg/cm2). The reaction mixture was filtered to remove palladium on charcoal, which was washed with ethanol (45 ml). The filtrate and washing were combined and concentrated in vacuo, and after adding acetone (30 ml) to the residue, the resulting mixture was concentrated in vacuo once again. Subsequently, to the residue obtained were added acetone (30 ml), diisopropylethylamine (4.4 g, 3.0 equivalent) and acetyl chloride (0.81 ml, 1.0 equivalent) successively, and the resulting mixture was refluxed for 10 minutes. The reaction mixture was concentrated in vacuo. To the residue obtained were added water (30 ml) and ethyl acetate (60 ml) successively, and after stirring, the resulting mixture was filtered to remove insoluble precipitates, which were washed with water (30 ml) and ethyl acetate (30 ml) successively. The filtrate and washing were combined, and both organic and aqueous layers were separated by partitioning. The separated aqueous layer was extracted with ethyl acetate (30 ml) once again, and the extract was combined with the organic layer separated above. The organic layer was washed with water (30 ml), dried over anhydrous magnesium sulfate and concentrated under reduced pressure to afford the title compound (2.86 g, yield: 91%) as colourless crystals.

Provenance & Evidence