Chapter 7.SE, Problem 38AP

Draw structures corresponding to the following systematic names:

(a) (4E)-2, 4-Dimethyl-l, 4-hexadiene

(b) cis-3, 3-Dimethyl-4-propyl-l, 5-octadiene

(c) 4-Methyl-l, 2-pentadiene

(d) (3E, 5Z)-2, 6-Dimethyl-1, 3, 5, 7-octatetraene

(e) 3-Butyl-2-heptene

(f) trans-2, 2, 5, 5-Tetramethyl-3-hexene

Interpretation Introduction

a) (4E)-2, 4-Dimethyl-1, 4-hexadiene.

Interpretation:

The structure corresponding to the systematic name (4E)-2, 4-dimethyl-1, 4-hexadiene is to be drawn.

Concept introduction:

The longest carbon chain containing the double bond to be chosen. Based on the name of the parent compound–the alkene name ends with the suffix–alkene. The chain is to be numbered from the end that gives the lowest number to the carbon in double bond. Substituents are to be numbered according to their positions in the chain and listed alphabetically. The position of the double bond is indicated by giving the number of the first alkene carbon before the name of the parent name. If more than one double bond is present, their positions are indicated with the suffixes -diene, -triene and so on. The isomer that has the higher ranked groups on each carbon are on the same side of the double bond is said to have Z configuration. If the higher ranked groups are on opposite sides, the alkene is said to have E configuration.

To draw:

The structure corresponding to the systematic name (4E)-2, 4-dimethyl-1, 4-hexadiene.

Answer to Problem 38AP

The structure corresponding to the systematic name (4E)-2, 4-dimethyl-1, 4-hexadiene is

Explanation of Solution

The name shows that the longest carbon chain should contain six carbons with two double bonds between C₂ & C₃ and C₄ & C₅. There should be two methyl substituents one on C₂ and other on C₄. Further higher ranked groups on each carbon should be in the opposite sides of the double bonds.

Conclusion

The structure corresponding to the systematic name (4E)-2, 4-dimethyl-1, 4-hexadiene is

Interpretation Introduction

b) cis-3, 3-Dimethyl-4-isopropyl-1, 5-octadiene.

Interpretation:

The structure corresponding to the systematic name cis-3, 3-dimethyl-4-isopropyl-1, 5-octadiene is to be drawn.

Concept introduction:

The longest carbon chain containing the double bond to be chosen. Based on the name of the parent compound–the alkene name ends with the suffix–ene. The chain is to be numbered from the end that gives the lowest number to the carbon in double bond. Substituents are to be numbered according to their positions in the chain and listed alphabetically. The position of the double bond is indicated by giving the number of the first alkene carbon before the name of the parent name. If more than one double bond is present, their positions are indicated with the suffixes -diene, -triene and so on. The isomer that has similar groups on each carbon on the same side of the double bond is called as the cis isomer. The isomer that has similar groups on each carbon on the opposite side of the double bond is called as thetrans isomer.

To draw:

The structure corresponding to the systematic name cis-3, 3-dimethyl-4-isopropyl-1, 5-octadiene.

Answer to Problem 38AP

The structure corresponding to the systematic name cis-3, 3-dimethyl-4-isopropyl-1, 5-octadiene is

Explanation of Solution

The name shows that the longest carbon chain should contain eight carbons with two double bonds between C₁ & C₂ and C₅ & C₆. There should be two methyl substituents on C₃ and an isopropyl group on C₄. Further similar groups in each carbon should be on the same sides of the double bonds.

Conclusion

The structure corresponding to the systematic name cis-3, 3-dimethyl-4-isopropyl-1, 5-octadiene is

Interpretation Introduction

c) 4-Methyl-1, 2-pentadiene.

Interpretation:

The structure corresponding to the systematic name4-methyl-1, 2-pentadiene is to be drawn.

Concept introduction:

The longest carbon chain containing the double bond to be chosen. Based on the name of the parent compound–the alkene name ends with the suffix–ene. The chain is to be numbered from the end that gives the lowest number to the carbon in double bond. Substituents are to be numbered according to their positions in the chain and listed alphabetically. The position of the double bond is indicated by giving the number of the first alkene carbon before the name of the parent name. If more than one double bond is present, their positions are indicated with the suffixes -diene, -triene and so on.

To draw:

The structure corresponding to the systematic name 4-methyl-1, 2-pentadiene.

Answer to Problem 38AP

The structure corresponding to the systematic name 4-methyl-1, 2-pentadiene is

Explanation of Solution

The name shows that the longest carbon chain should contain five carbons with two double bonds between C₁ & C₂ and C₂ & C₃. There should be amethyl substituent on C₄.

Conclusion

The structure corresponding to the systematic name 4-methyl-1, 2-pentadiene is

Interpretation Introduction

d) (3E, 5Z)-2, 6-Dimethyl-1, 3, 5, 7-octatetraene.

Interpretation:

The structure corresponding to the systematic name (3E, 5Z)-2, 6-dimethyl-1, 3, 5, 7-octatetraene is to be drawn.

Concept introduction:

The longest carbon chain containing the double bond to be chosen. Based on the name of the parent compound–the alkene name ends with the suffix–ene. The chain is to be numbered from the end that gives the lowest number to the carbon in double bond. Substituents are to be numbered according to their positions in the chain and listed alphabetically. The position of the double bond is indicated by giving the number of the first alkene carbon before the name of the parent name. If more than one double bond is present, their positions are indicated with the suffixes -diene, -triene and so on. The isomer that has the higher ranked groups on each carbon are on the same side of the double bond is said to have Z configuration. If the higher ranked groups are on opposite sides, the alkene is said to have E configuration.

To draw:

The structure corresponding to the systematic name (3E, 5Z)-2, 6-dimethyl-1, 3, 5, 7-octatetraene.

Answer to Problem 38AP

The structure corresponding to the systematic name (3E, 5Z)-2, 6-dimethyl-1, 3, 5, 7-octatetraene is

Explanation of Solution

The name shows that the longest carbon chain should contain eight carbons with two double bonds between C₂ & C₃ and C₆ & C₇. There should be two methyl substituents one on C₂ and other on C₆. Further higher ranked groups on C₂ & C₃ must be placed on the opposite sides of the double bond. The higher ranked groups on C₆ & C₇ must be placed on the same side of the double bond.

Conclusion

The structure corresponding to the systematic name (3E, 5Z)-2, 6-dimethyl-1, 3, 5, 7-octatetraene is

Interpretation Introduction

e) 3-Butyl-2-heptene.

Interpretation:

The structure corresponding to the systematic name3-butyl-2-heptene is to be drawn.

Concept introduction:

The longest carbon chain containing the double bond to be chosen. Based on the name of the parent compound–the alkene name ends with the suffix–ene. The chain is to be numbered from the end that gives the lowest number to the carbon in double bond. Substituents are to be numbered according to their positions in the chain and listed alphabetically. The position of the double bond is indicated by giving the number of the first alkene carbon before the name of the parent name. If more than one double bond is present, their positions are indicated with the suffixes -diene, -triene and so on.

To draw:

The structure corresponding to the systematic name 3-butyl-2-heptene.

Answer to Problem 38AP

The structure corresponding to the systematic name 3-butyl-2-heptene is

Explanation of Solution

The name shows that the longest carbon chain should contain seven carbons with a double bond between C₂ & C₃. There should be a butyl substituent on C₃.

Conclusion

The structure corresponding to the systematic name 3-butyl-2-heptene is

Interpretation Introduction

f) trans-2, 2, 5, 5-Tetramethyl-3-hexene.

Interpretation:

The structure corresponding to the systematic name trans-2, 2, 5, 5-tetramethyl-3-hexene is to be drawn.

Concept introduction:

The longest carbon chain containing the double bond to be chosen. Based on the name of the parent compound–the alkene name ends with the suffix–ene. The chain is to be numbered from the end that gives the lowest number to the carbon in double bond. Substituents are to be numbered according to their positions in the chain and listed alphabetically. The position of the double bond is indicated by giving the number of the first alkene carbon before the name of the parent name. If more than one double bond is present, their positions are indicated with the suffixes -diene, -triene and so on. The isomer that has similar groups on each carbon on the same side of the double bond is called as the cis isomer. The isomer that has similar groups on each carbon on the opposite side of the double bond is called as the trans isomer.

To draw:

The structure corresponding to the systematic name trans-2, 2, 5, 5-tetramethyl-3-hexene.

Answer to Problem 38AP

The structure corresponding to the systematic name trans-2, 2, 5, 5-tetramethyl-3-hexene is

Explanation of Solution

The name shows that the longest carbon chain should contain six carbons with a double bond between C₃ & C₄. There should be four methyl substituents two on C₃ and two on C₅. Further similar groups in each carbon should be on the opposite sides of the double bonds.

Conclusion

The structure corresponding to the systematic name trans-2,2,5,5-tetramethyl-3-hexene is