Hydrochloric Acid → HCID 21914108, compound

Temperature

0 °C

5-chloro-2,3-dihydroxy-1H-indole-2-carboxylic acid, methyl ester (0.00761 mole) was dissolved in methanol (25 ml) and cooled to 0° C. NH3 was bubbled in for 10 minutes. The flask was stoppered and allowed to warm to room temperature. The mixture was stirred overnight. TLC showed the reaction was mostly complete. The sample was concentrated to ±⅓ volume, cooled, and filtered, rinsing resulting solid with ice cold methanol (2 ml) and then dried ion the air, yielding 0.74 g of 5-chloro-2,3-dihydro-1H-indole-2-carboxamide (intermediate 7, mp. 151-152° C.). b) Triethylamine (0.02080 mole) was added to intermediate (7) (0.09632 mole) dissolved in trichloromethane (700 ml). The mixture was cooled to 5° C. Acetyl chloride (0.2480 mole) was added over 2 minutes with stirring. After 5 minutes, a precipitate formed. The ice bath was removed, and the container allowed to sit for 15 minutes. Ice water (250 ml) was added, and the mixture was stirred for 10 minutes. The sample was filtered, rinsed with water and trichloromethane. The solid was suspended in water (200 ml), and swirled for 10 minutes. Trichloromethane (200 ml) was added and the mixture was stirred, then filtered and rinsed with water and trichloromethane, and then dried to the air overnight, yielding 19.71 g of 1-acetyl-5-chloro-2,3-dihydro-1H-indole-2-carboxamide (intermediate 8). c) Triethylamine (0.41291 mole) was added to intermediate (8) (0.08258 mole) suspended in dichloromethane (500 ml) at 0° C. Trichloroacetyl chloride (0.20645 mole) was added over 10 minutes. When the reaction appeared sluggish, an additional portion of triethylamine (20 ml) and then more trichloroacetyl chloride (7.6 ml) were added, and the mixture was stirred for 2 hours at low temperature. The ice bath was removed, and the mixture was allowed to sit for 2 hours. This resulted in a darker colored reaction, which was re-cooled to 0° C. Ice cold water (150 ml) was slowly added, and the mixture was stirred for 5 minutes. The layers were separated, and the organic phase was washed (ice cold 3N HCl, saturated NaHCO3), dried, filtered, and concentrated. The residue was triturated in ice cold diethylether (40 ml). Filtration, rinsing with ice cold diethylether (10 ml), yielding 15.13 g of 1-acetyl-5-chloro-2,3-dihydro-1H-indole-2-carbonitrile (intermediate 9, mp. 140-142° C.). d) HCl (as a 2 M solution) was added slowly to intermediate (9) until gas evolution was noted. Then stopped adding the prepared HCl (2N in diethylether), and suspended HCl in diethylether (150 ml) and then ethanol (0.042 mole) was added. The mixture was cooled to 0° C. and HCl (gas) was added over an hour, with an oil precipitating out. The reaction was diluted to 1 l with diethylether. More oil precipitates, and no solid formed after sitting for 1 hour. The diethylether was decanted off. The residue was diluted (diethylether, 500 ml). The solid begins to form, and the mixture was stirred for 2 hours. The sample was filtered, rinsing with diethylether. The sample was placed under vacuum, yielding 6.41 g of ethyl 1-acetyl-5-chloro-2,3-dihydro-1H-indole-2-carboximidate monohydrochloride (intermediate 10).

1. customprecipitating out
2. additionThe reaction was diluted to 1 l with diethylether
3. customMore oil precipitates
4. customno solid formed
5. customThe diethylether was decanted off
6. additionThe residue was diluted (diethylether, 500 ml)
7. customto form
8. filtrationThe sample was filtered
9. washrinsing with diethylether

ORD record

ord-ace2f30d72a94d5090518572fe34ef04

Source dataset

uspto-grants-2011_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07947713B2