Propionic Acid → 4-(2-Chloro-9-xanthenylidene)-1-methylpiperidine maleate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A mixture of 12.5 g. (0.038 m.) of the xanthene-9-ol, 14.0 g. (0.76 m.) of o-sulfobenzoic anhydride and 380 ml. of propionic acid is refluxed for three hours. The reaction mixture is heated in vacuo at 100° C. and the resulting syrup is dissolved in water, made strongly basic with 40% sodium hydroxide solution, extracted with ether, and the dried extract is evaporated. The residual free base is dissolved in ethyl acetate and maleic acid (4.4 g.) is added to yield 4-(2-chloro-9-xanthenylidene)-1-methylpiperidine maleate, m.p. 206°-207° C.

Herkunft & Nachweise