Al Farabi Kazakh National University

Al Farabi Kazakh National University

Faculty of chemistry and chemical technology

SIW: Cyclic compound

Done by: Kaydar Bayan

Almaty, 2014

Cyclic compounds

v Sometimes the carbon atoms in an alkane will form a complete ring. Such compounds are called cyclic compounds or ring compounds. When this happens, the prefix cyclo- is added to the name.

Thus, the alkane with the six-carbon ring shown here (also shown in example 18 in your workbook) is called cyclohexane.

v If groups of atoms are attached to the ring, then the appropriate prefixes are added to the name as shown in the following examples.

CH2 - CH2

/ \

CH2 CH-CH3

\ /

CH2 - CH2

methylcyclohexane

Note that it is not necessary to use the number prefix when only one group is attached to the ring. Thus, this compound is called methylcyclohexane.

CH2 - CH2

/ \

CH2 CH-CH3

\ /

CH2 - CH-CH3

1,2-dimethylcyclohexane

However, when two groups are attached, it is necessary to show where they are attached with respect to one another. So, this compound is 1,2-dimethylcyclohexane.

ü In chemistry, a cyclic compound is a compound in which a series of atoms is connected to form a loop or ring. While the vast majority of cyclic compounds are organic, a few inorganic substances form cyclic compounds as well, including sulfur, silanes, phosphanes, phosphoric acid, and triboric acid. Cyclic compounds may or may not be aromatic. Benzene is aromatic while cyclohexane is not. The term "polycyclic" is used when more than one ring is formed in a single molecule for instance in naphthalene, and the term macrocycle is used for a ring containing more than a dozen atoms.

1. Cycloheptane, a non-aromatic cyclic compound.

2. Benzene, a cyclic compound.

2. Naphthalene, a polycyclic compound.

2. Porphyrin, a macrocyclic compound.

3. Pentazole, an inorganic cyclic compound.

Ø Alicyclic compounds are named according to the IUPAC system of nomenclature by attaching the prefix cyclo- to the name of the corresponding open chain hydrocarbon possessing the same number of carbon atoms. The common names resemble the IUPAC names. For example: Cyclo pentane, cyclo butane etc.

References:

1. www.wikipedia.org

2. www.xumuk.ru

3. http://sparkcharts.sparknotes.com

4. http://www.britannica.com/EBchecked/topic/147930/cyclic-compound

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