IMAT 2013 Q46 [Chemical Reactions]

The compound (CH_3)_2CHCH_2NH_2 can be synthesised by the following route.


What types of reaction are used in stages 1, 2 and 3?

A. 1=substitution; 2=addition; 3=reduction
B. 1=substitution; 2=addition; 3=hydrolysis
C. 1=addition; 2=substitution; 3=reduction
D. 1=addition; 2=addition; 3=reduction
E. 1=addition; 2=substitution; 3=hydrolysis

In the first reaction, we can see that our double bond in Propene has been broken, and HBr_3 has been added. Alkenes undergo this type of reaction, in its simplest terms an organic reaction where two or more molecules combine to form a larger one called an addition reaction.

This narrow down our possible answers to C, D or E.

In our second reaction, Br has been replaced or substituted for a nitrile or cyanide group. We can hence call this a substitution reaction, a reaction in which the functional group of one chemical compound is substituted by another group.

Now it’s between C and E.

The last reaction, we can see that Nitrogen has been reduced with hydrogen. It’s also obviously not a hydrolysis reaction. Our answer should be C.