Benzene → 1-(2-Amino-4-chlorophenyl)-5-chloroindoline hydrochloride ethanolate

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Reaction Steps

A Parr bottle, charged with 12.4 g (0.040 mole) of 5-chloro-1-(4-chloro-2-nitrophenyl)indoline of Example 8a, 100 ml of benzene, 100 ml of absolute ethanol and 0.5 g of 1% Pt/C was shaken under an initial hydrogen pressure of 57 psig until uptake ceased. The catalyst was then removed by filtration and the filtrate was concentrated in vacuo to an oil weighing 11.2 g (100%). This was dissolved in 30 ml of ethanol and then 30 ml of ether saturated with hydrogen chloride was added. An additional 500 ml of plain ether was added, and the mixture was stirred at 0° C., to maximize precipitation. The hydrochloride salt was collected, dried, and found to weigh 9.2 g (73%), m.p. 174°-178° C. Recrystallization from ethanol (charcoal) afforded 1-(2-amino-4-chlorophenyl)-5-chloroindoline hydrochloride ethanolate in 58% overall yield, m.p. 177°-180° C.

Provenance & Evidence