C5H11N

C5H11N is the molecular formula used for a group of amines that contain five carbon atoms and one nitrogen. This formula is shared by several structural isomers, including cyclic amines such as piperidine and methyl-substituted pyrrolidines (for example 1-methylpyrrolidine and 2-methylpyrrolidine). The ring systems and substitution patterns give rise to distinct physical and chemical properties, even though all have the same nominal formula.

The most prominent representatives are piperidine, a six-membered saturated heterocycle, and the methylpyrrolidines, which are five-membered rings containing nitrogen with a methyl substituent. These compounds are used as solvents, reagents, and building blocks in organic synthesis, and they often serve as bases due to the lone pair on nitrogen. Piperidine, in particular, is widely employed in pharmaceutical and dye chemistry, and it can be prepared by hydrogenation of pyridine.

Because C5H11N encompasses several isomeric structures, properties such as boiling point, solubility, and basicity vary among individual isomers. In general, amines of this type are basic and form salts with acids; they are typically colorless liquids or low-melting solids at room temperature and can be irritating to skin and eyes. As with other nitrogen-containing heterocycles, safety data sheets should be consulted for handling and storage.

See also: amines, heterocycles, pyrrolidine, piperidine, organic synthesis.