Chapter 22, Problem 42PP

Interpretation Introduction

Interpretation: For a given C₅H₁₃N molecular formula, all the possible tertiary constitutional isomers and the names with structures have to be found with chirality nature if any.

Concept Introduction: The arrangement of atoms that are bonded together determines its constitution and molecular formula of that particular compound.  This concept is referred as structural isomers or in more modern term constitutional isomers.

Each atom has a typical valency or valence which is defined as the ability of an atom to form a chemical bond with other atoms.  For example, carbon has four valence or tetravalent that means carbon has the capacity to form four bonds with other elements or other atoms.  Nitrogen and hydrogen atoms are trivalent and monovalent in nature.

If ,  and groups are attached to the parent carbon, they are called primary, secondary and tertiary amines respectively.

There are two ways followed to name the compound.  First one is the method of giving general name in which name of the alkyl group followed by amine name is given.  Second one is the method giving IUPAC name in which name of the alkane group followed by amine name is given.

The length of the chain which is having more number of carbon atoms is selected as the parent or main chain.  Other chains are considered as substituents to the main chain.  Position of the substituents should be included in the name.  If one, two, three, four, five, six, etc carbons are activating as the main chain in IUPAC system, then the name of the compound comes as methane, ethane, propane, butane, pentane, hexane, etc. which are the name of alkanes.  If one, two, three, four, five, six, etc carbons are activating as the main chain in general name method, then the name of the compound comes as methyl, ethyl, propyl, butyl, pentyl, hexyl, etc. which are the name of alkyl groups.  If substituent groups are attached to nitrogen atom as in the case of tertiary or secondary amines, the name is given as N-alkyl name of the substituent.

If a carbon is attached with four different groups, that carbon atom is chiral in nature.  It shows optical isomerism.

To find: Draw all the possible tertiary constitutional isomers and assign the corresponding name for C₅H₁₃N with chirality if any.

Carbon (C), nitrogen (N) and hydrogen (H) valency in C₅H₁₃N