L-(-)-Ephedrine

This alkaloid was first isolated by Kanao from the Chinese drug 'Ma-Huang' (Ephedra sinica Stapf.) and later by Wolfes from E. helvetica C. A. Meyer and E. distachya Linn. It forms a crystalline mass and has [α] ²⁰ _D - 14.56° (EtOH). Several crystalline salts and derivatives are known: the hydrochloride has m.p. 171-2°C; [α] ²⁰ _D- 33.27° (H20); the sulphate dihydrate, m.p. 285-6°C (dry, dec.); [α] ²⁸ _D- 31.99° (H20); the aurichloride, m.p. 188°C; platinichloride, m.p. 221°C (dec.); (-)-hydrogen tartrate, m.p. about 160° after sintering at 130°C; oxalate, m.p. 245°C (dec.) and the p-nitrobenzoyl derivative, m.p. 175-6°C; [α] ²⁸ _D- 49.58° (CHCI3).
The (+)-form has m.p. 52°C; [α] ²⁷ _D + 14.76° (EtOH), yielding a hydro_x0002_chloride, m.p. 171-2°C; [α] ²⁷ _D + 33.4° (EtOH); sulphate dihydrate, m.p. 285- 6°C (dry, dec.); [α] ²⁷ _D+ 31.51 0 C (H20); aurichloride, m.p. 188°C (dec.) and platinichloride, m.p. 221.5°C (dec.). The (±)-form crystallizes as colourless plates from Et20, m.p. 104-5°C and also furnishes a series of crystalline salts and derivatives.