H | C H_{2}C---CH_{2} / \\ | | HC C------HC CH_{2} ║ | \ / HC CH N \ // | N CH_{3} =Hygrine=, C_{7}H_{13}NO, from coca leaves, is an acetic acid salt of pyrrolidine, represented by the following formula: H_{2}C---CH--OC·CH_{3} | | H_{2}C CH_{2} \ / N | CH_{3} =Atropine= and =hyoscyamine=, C_{17}H_{23}NO_{3}, are optical isomers. Atropine is an extremely poisonous, white crystalline compound, which is obtained from deadly nightshade and henbane, and used in medicine, in minute doses, as an agent for reducing temperature in acute cases of fevers. Structurally, it is a tropic acid ester of tropane, represented by the following formula: H_{2}C---CH--------CH_{2} C_{6}H_{5} | | | | | N-CH_{3} CHOOC---CH | | | | H_{2}C---CH--------CH_{2} CH_{2}OH =Cocaine=, C_{17}H_{21}NO_{4}, is found in coca leaves. It is a white crystalline solid, which is largely used as a local anæsthetic for minor surgical operations. Its structural formula is H_{2}C---CH--------HC-OOC·CH_{3} | | | | N-CH_{3} HC-OOC·C_{6}H_{5} | | | H_{2}C---CH---------CH_{2} It is, therefore, a di-ester of acetic and benzoic acids with tropane. =Cinchonine=, C_{19}H_{22}N_{2}O, and =quinine=, C_{20}H_{24}N_{2}O_{2}, are alkaloids found in cinchona bark. They are white crystalline solids, which are extensively used in medicine. They have been shown to contain a quinoline group combined with modified piperidine groups, as represented in the following formulas: H | N C / \ / \ /|\ | | | / | \ | | | H_{2}C HCH CH-CH=CH_{2} \ / \ / | | | CH-CHOH-HC HCH CH_{2} \ | / N Cinchonine