Cycloalkanes: Introduction, Structure and Physical Properties
Cycloalkanes are a sub-family of alkanes. They have the molecular formula CnH2n representing a ring system without a chain terminus. Like their alkane counterparts, they are saturated and their name with the additional prefix cyclo- is derived from the number of C atoms in the ring.
Life on earth would not be possible without these ring compounds, because the majority of organic compounds found in nature contain rings in their molecules. Many of these are important medicinal compounds, pigments or fragrances. Terpenes and steroids are two important classes of natural products. .
In nature, terpenes are widely distributed in essential oils. Among other applications, they are being used as fragrances and spices in perfume and food industries, respectively. Additionally, they also find applications as insecticides.
Steroids often exhibit physiological activity. Some of them act as hormones, e.g. as the active ingredient in the contraceptive pill. Cholesterol is one of the mostly distributed steroids because it is found in nearly all animal and human tissues. The basic steroidal framework contains three fused cyclohexane rings and one terminal cyclopentane ring. The rings exist in chair conformations and are mostly trans configured.