University of Texas

CH 320N

Interesting and Useful Amines • Many low molecular weight amines have foul odors. • Trimethylamine [(CH3 ) 3N], formed when enzymes break down certain fish proteins, has the characteristic odor of rotting fish. That is why we add lemon to fish! • Putrescine (NH2CH2CH2CH2CH2NH2 ) and cadaverine (NH2CH2CH2CH2CH2CH2NH2 ) are both poisonous diamines with putrid odors. They too are present in rotting fish (and other smelly stuff). • Naturally occurring amines derived from plant sources are called alkaloids. 3 Interesting and Useful Amines Figure 25.5 Three common alkaloids— Atropine, nicotine, and coniine 4 Interesting and Useful Amines • Histamine, a rather simple triamine that is present in many tissues, is responsible for a wide variety of physiological effects. • Understanding the physiological properties of histamine has helped chemists design drugs to counteract some of its undesirable effects. Antihistamines bind to the same active site as histamine in the cell, but they evoke a different response. Examples are brompheniramine and cimetidine. 5 Interesting and Useful Amines • A large number of physiologically active compounds are derived from 2-phenethylamine (C6H5CH2CH2NH2 ). These compounds include adrenaline, noradrenaline, methamphetamine, and mescaline. Each contains a benzene ring bonded to a twocarbon unit with a nitrogen atom (shown in red). 6 Interesting and Useful Amines • Most of these are analogues of the neurotransmitter dopamine. Dopamine—A neurotransmitter 7 Interesting and Useful Amines • Cocaine, amphetamines, and se