Amines and Other Organic Compounds of Nitrogen

The amines are derivatives of ammonia, NH3, obtained by replacing one or more of the hydrogen atoms by organic radicals. The lighter amines, such as methylamine, CH3NH2, dimethylamine, (CH3)9NH, and tri-methylamine, (CH3)3N, are gases. 

Aniline is aminobenzene, CeHsNHo. It is a colorless oily liquid, which on standing becomes dark in color because of oxidation to highly colored derivatives. It is used in the manufacture of dyes and other chemicals. 

Many substances that occur in plant and animal tissues are compounds of nitrogen. Especially important are the proteins and nucleic acids, which are discussed in the following chapters. The principal product of the metabolism of proteins in the human body is urea, (NH-2)2CO. It is the main nitrogenous constituent of urine. 

Heterocyclic compounds are cyclic compounds in which one or more atoms other than carbon (usually nitrogen, oxygen, or sulfur) are present in the ring. An example is pyridine, C5H5N, a colorless liquid with an unpleasant odor, which is among the products of distilling coal. The electronic structure of pyridine can be described as a hybrid of several valence-bond structures  

The resonance energy of pyridine, relative to one of the Kekule-like structures, is 180 kJ mole . Pyridine is a base in acidic solution it adds a proton to the unshared electron pair of the nitrogen atom, forming the pyridonium ion, C5H5NH.  

---