Question

Using your roadmaps as a guide, show how to convert 1-bromopentane and sodium cyanide into \(N\)-hexylhexanamide. You must use 1-bromopentane and sodium cyanide as the source of all carbon atoms in the target molecule. Show all reagents and all molecules synthesized along the way.

Short answer

Question: Outline the steps required to synthesize N-hexylhexanamide using 1-bromopentane and sodium cyanide. Answer: To synthesize N-hexylhexanamide from 1-bromopentane and sodium cyanide, follow these steps: 1. React 1-bromopentane with sodium cyanide to form 1-pentanenitrile. 2. Hydrolyze 1-pentanenitrile to obtain hexanoic acid. 3. Convert hexanoic acid into its acid chloride, and then react it with hexylamine to produce N-hexylhexanamide.

Step-by-step solution

Formation of 1-pentanenitrile

In this first step, react 1-bromopentane with sodium cyanide under mild conditions. The sodium cyanide will attack the carbon atom bonded to the bromine in a nucleophilic substitution reaction, replacing the bromide group with the cyanide group. This reaction will form 1-pentanenitrile as the product. The overall reaction is as follows: $$ C_5H_{11}Br + NaCN \rightarrow C_5H_{11}CN + NaBr $$

Hydrolysis of 1-pentanenitrile to form hexanoic acid

In this step, carry out the hydrolysis of 1-pentanenitrile under acidic conditions. The nitrile group (CN) will be converted to a carboxylic acid (COOH) forming hexanoic acid. The reaction is given by: $$ C_5H_{11}CN + 2 H_2O \xrightarrow[H^+]{heat \, and \, stir} C_5H_{11}COOH + NH_3 $$

Formation of N-hexylhexanamide

Now, you'll need to convert hexanoic acid into N-hexylhexanamide. First, convert hexanoic acid into its acid chloride by reacting it with thionyl chloride (SOCl2) as follows: $$ C_5H_{11}COOH + SOCl_2 \rightarrow C_5H_{11}COCl + SO_2 + HCl $$ Next, react hexylamine (C6H15N) with hexanoyl chloride to form N-hexylhexanamide: $$ C_5H_{11}COCl + C_6H_{15}N \rightarrow C_5H_{11}CONH(C_6H_{13}) + HCl $$ In summary, to form N-hexylhexanamide from 1-bromopentane and sodium cyanide, three major steps are required: 1. Formation of 1-pentanenitrile by reacting 1-bromopentane and sodium cyanide. 2. Hydrolysis of 1-pentanenitrile to form hexanoic acid. 3. Conversion of hexanoic acid into N-hexylhexanamide by first converting it into its acid chloride and then reacting it with hexylamine.