Chapter 18, Problem 37P

(a) Give the IUPAC name for A and B. (b) Draw the product formed when A or B is treated with each reagent: 1. ${\text{NaBH}}_{\text{4}},{\text{CH}}_{\text{3}}\text{OH}$; 2. ${\text{CH}}_{\text{3}}\text{MgBr}$, then ${\text{H}}_{\text{2}}\text{O}$; 3. ${\text{Ph}}_{\text{3}}{\text{P=CHOCH}}_3$;4. ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{NH}}_{\text{2}}$, mild acid; 5. ${\text{HOCH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{OH}$, ${\text{H}}^{\text{+}}$.

Interpretation Introduction

(a)

Interpretation: The IUPAC name for A and B is to be determined.

Concept introduction: IUPAC nomenclature is a systematic way of naming the organic compounds. The basic principles of IUPAC naming for hydrocarbon are:

1. The hydrocarbon is named after the carbon chain containing higher number of carbon atoms.

2. For functional group such as aldehyde suffix ‘al’ and for ketone suffix ‘one’ is added to the name.

3. When the chain is substituted with different substituents, then the numbering is done according to priority.

Answer to Problem 37P

The IUPAC name for A and B is $\text{3, 3-dimethylbutanal}$ and $\text{5-isopropyl-2-methylcyclohexanone}$ respectively.

Explanation of Solution

The given compound is,

Figure 1

The red coloured balls have two bonds. So, these are the oxygen atoms. Black coloured atoms have four bonds. So, these are the carbon atoms. The grey coloured balls have one bond. So, these are the hydrogen atoms. The molecular structure is,

Figure 2

The parent hydrocarbon is butane. The functional group present is aldehyde. Two methyl groups are present on third carbon atom. When same substituents are present, then prefix depends on the number of substituents. The IUPAC name of the compound is $\text{3, 3-dimethylbutanal}$.

The given compound is,

Figure 3

The red coloured balls have two bonds. So, these are the oxygen atoms. Black coloured atoms have four bonds. So, these are the carbon atoms. The grey coloured balls have one bond. So, these are the hydrogen atoms. The molecular structure is,

Figure 4

The parent hydrocarbon is cyclohexane. The functional group present is ketone. Methyl group is present on fifth carbon atom and isopropyl group is present on third carbon atom. The IUPAC name of the compound is $\text{5-isopropyl-2-methylcyclohexanone}$.

Conclusion

The IUPAC name for A and B is $\text{3, 3-dimethylbutanal}$ and $\text{5-isopropyl-2-methylcyclohexanone}$ respectively.

Interpretation Introduction

(b)

Interpretation: The products formed when B is treated with given reagents are to be drawn.

Concept introduction: The metal hydride reagents are good reducing agents such as ${\text{NaBH}}_{\text{4}}$. They can be used to reduce carbonyl compounds, conjugated double or triple bonds and $\text{C}-\text{X}$ bond in alkyl halides and epoxides.

Grignard reagents are organometallic compounds which are prepared using alkyl halides in presence of magnesium metal in dry ether. These reagents act as strong nucleophiles and bases.

Answer to Problem 37P

The products formed when B is treated with given reagents are,

Explanation of Solution

1. In the presence of ${\text{NaBH}}_{\text{4}},{\text{CH}}_{\text{3}}\text{OH}$, compound B is reduced to alcohol. The corresponding reaction is shown below.

Figure 5

The product formed is $\text{5-isopropyl-2-methylcyclohexanol}$.

2. The Grignard reagent reacts with compound B to form secondary alcohol. The corresponding reaction is shown below.

Figure 6

The product formed is $\text{5-isopropyl-1, 2-dimethylcyclohexanol}$.

3. When compound B is treated with ${\text{Ph}}_{\text{3}}{\text{P=CHOCH}}_3$, the new carbon-carbon double bond is formed between the negatively charged carbon atom of Wittig reagent and carbonyl carbon of aldehyde. The corresponding reaction is as follows,

Figure 7

The product formed is $\text{(E)-4-isopropyl-2-(methoxymethylene)-1-methylcyclohexane}$.

4. The compound B reacts with ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{NH}}_{\text{2}}$ in presence of mild acid to form imine. The corresponding reaction is as follows,

Figure 8

The product formed is $\text{(E)-N-(5-isopropyl-2-methylcyclohexylidene)propan-1-amine}$.

5. The product formed by the reaction of compound B with ethylene glycol in the presence of $p\text{-toluenesulfonicacid}$ is shown below.

Figure 9

Conclusion

The products formed when B is treated with given reagents are shown in Figure 5, Figure 6, Figure 7, Figure 8 and Figure 9.