UINIDINE (Conquinine)

Description

An isomeride of quinine (q.v.), this alkaloid occurs in relatively small quantities in most Cinchona barks, especially in those of C. amygdalifolia, C Calisaya and C. pitayensis. It has also been discovered in the bark of Remija pedunculata. The alkaloid is dextrorotatory with [α]_D + 262° (EtOH), [α]¹⁵_D + 236.8° (97% EtOH), + 243.5° (99% EtOH) or + 230° (CHC1 3). It forms colourless crystals with 2.5 H20 from aqueous EtOH, losing 0.5 H20 on exposure to air. When crystallized from dry EtOH it forms prisms containing solvent which is lost at lOOuC. Quinidine is alkaline in solution and behaves as a diacidic base forming two series of salts. The hydrochloride monohydrate forms asbestos-like prisms, m.p. 258-9°C (dry, dec.); [α]²⁰_D + 200° (H20); the dihydrochloride monohydrate forms prisms, readily soluble in EtOH; the dihydrobromide crystallizes well from water and has [α]¹⁵_D + 223° (H20); the neutral hydriodide is sparingly soluble in H20 and is the form in which the alkaloid is normally estimated. The neutral sulphate dihydrate forms colourless prisms and has [α]_D + 184.17° (CHC13) while the acid sulphate yields hair-like needles, [α]¹⁵_D + 247.8° (H20) or + 256.4° (0.1 N/H2S04). The alkaloid gives a positive thalleioquin reaction and is fluorescent in dilute H2S04.

References

Butler, Cretcher., 1. A mer. Pharm. Assoc., 22, 414 (1933)
Thron, Dirscherl., Annalen, 515,252 (1935)
Monnet.,l. Pharm. Chim., 22, 112 (1935)