Figure 1.

Cinchona alkaloids: structures to illustrate the stereochemistry. Q = quinine, QD = quinidine, EQ = epiquinine, EQD = epiquinidine, HQ = hydroquinine, HQD = hydroquinidine, CD = cinchonidine, C = cinchonine, ECD = epicinchonidine, EC = epicinchonine.