Organic and biochemistry Alcohols Classification of alcohols Nomenclature of alcohols Assisatnce Lecturer Amjad Ahmed Jumaa

Alcohols: Alcohols are compounds of the general formula ROH, where R is any alkyl or substituted alkyl group. The group may be primary, secondary, or tertiary. It may be contain a double bond, a halogen atom, or an aromatic ring. For example

Classification: An alcohol is classified according to the kind of carbon that bears the –OH group. Nomenclature of alcohols: IUPAC nomenclature of alcohols: The rules are:

1-select as the parent structure the longest continuous carbon chain that contains the –OH group. The parent structure is known as ethanol, propanol, butanol, etc. depending upon the number of carbon atoms. Each name is derived by replacing the terminal –e of the corresponding alkane name by –ol. 2-indicate by a number the position of the –OH group in the parent chain, generally using the lowest possible number for this purpose. 3-indicate by numbers the positions of the other groups attached to the parent chain. Look at the following examples:

Problem: give the structure and the name for the following alcohols: 1-(1-methylpentyl alcohol) (or 2-hexanol) 2-(2-methyl-2-pentanol) 3-(6-methyl-3-heptanol). Solution:

Give the IUPAC names for the following alcohols: Follow problem: give the name and the structure for the following alcohols: 1-(2, 2-dimethyl-1-propanol) 2-(3-phenyl-1-propanol) 3-(2, 4-dimethyl-3-pentanol) 4-(3-hexanol) 5-(4-ethyl-5-methyl-2-octanol) Give the IUPAC names for the following alcohols: 1) CH3CH(OH)CH2CH(Cl)CH2CH3. 2) C6H5CH2OH. 3) P-ClC6H4CH2OH. 4) CH3CH(Br)CH2CHOH. 5) CH3CH2OH .