Question

IUPAC name of glycine is:
A. 2-Aminopropanoic acid
B. 2-Aminobutanoic acid
C. 2-Aminoethanoic acid
D. 2-Aminopent-1,5-dioic acid

Answer 1

Hint: International Union of Pure and Applied Chemistry have set some rules which need to be followed when a new organic molecule is discovered and it is unique to that organic molecule only. Glycine is the common name of this molecule because some molecules have given these common names as they are used more every day.

Complete Solution :
If we look at the formula of glycine which is $N{{H}_{2}}C{{H}_{2}}COOH$, where we see that, to find the long carbon chain there is chain of two carbons along with the Carboxylic acid, therefore the suffix will be ethane. Now, there are two functional groups present already which are amine and carboxylic acid, according to the rule, the functional group with highest priority order will be used as suffix and the one with the less priority order will be used as prefix. Here, the amine will be prefix and its name is -amine and carboxylic will be used as a suffix with ending -oic.
- The numbering will also start from the carboxylic acid carbon which means the prefix is attached at 2nd position. Hence, the name will be 2-Aminoethanoic acid.
So, the correct answer is “Option C”.

Note: There is a priority order table of functional groups which must be learned by heart otherwise, one will not be able to attempt the questions which are related to the nomenclature:
Carboxylic acids > Acid anhydrides > Esters > Acyl Halides > Amides > Nitriles > Aldehydes > Ketones > Thiols > Amines etc.