1,1-Dichloroethane → 3-[[N-(5,5-dimethyl-1-pyrrolin-2-yl)-p-anisidino]methyl]indole hydrochloride

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Reaction Steps

Phosphorus oxychloride (1.53 g., 0.01 mole), 3-(p-anisidinomethyl)indole, (2.52 g., 0.01 mole), 5,5-dimethyl-2-pyrrolidinone (1.13 g., 0.01 mole), and triethylamine (1.01 g., 0.01 mole) in 50 ml. of 1,2-dichloroethane is reacted according to the procedure of Example 36. After standing for 6 hr. at ice bath temperature, the reaction mixture is filtered affording the crude hydrochloride salt (1.45 g.) of the product, m.p. 188°-191° C. The dichloroethane filtrate is made basic with 10% sodium hydroxide, separated, dried over magnesium sulfate, acidified with ethanolic hydrogen chloride, and concentrated under reduced pressure. Trituration of the residue thus obtained with acetone yields a second crop of the hydrochloride, (0.76 g.), m.p. 191°-194° C. The hydrochloride fractions are combined and converted to the free base (m.p. 83°-85° C.) in the usual manner by dissolving in water and making basic with sodium hydroxide followed by extraction with ether. The hydrochloride salt is reprepared by taking the free base up in ethanol and acidifying with ethanolic hydrogen chloride to provide analytically pure 3-[[N-(5,5-dimethyl-1-pyrrolin-2-yl)-p-anisidino]methyl]indole hydrochloride, m.p. 188.5°-190.5° C. (dec.) (corr.)

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