Question

Names of some compounds are given. Which one is not correct in IUPAC system?

• A. $ \underset{3-\text{methyl}-2-\text{butanol}}{\mathop{C{{H}_{3}}-\underset{OH}{\mathop{\underset{|}{\mathop{CH}}\,}}\,-\underset{C{{H}_{3}}}{\mathop{\underset{|}{\mathop{CH}}\,}}\,-C{{H}_{3}}}}\, $
• B. $ \underset{4-\text{methyl}-2-\text{pentyne}}{\mathop{C{{H}_{3}}-C{{H}_{2}}\equiv C}}\,-CH{{(C{{H}_{3}})}_{2}} $
• C. $ \underset{2-\text{ethyl}-3-\text{methyl}-\text{but}-1-\text{ene}}{\mathop{C{{H}_{3}}-C{{H}_{2}}-\underset{C{{H}_{2}}}{\mathop{\underset{||}{\mathop{C}}\,}}\,-\underset{C{{H}_{3}}}{\mathop{\underset{|}{\mathop{CH}}\,}}\,-C{{H}_{3}}}}\, $
• D. $ \underset{3-\text{methyl}-4-\text{ethyl}\,\text{heptane}}{\mathop{C{{H}_{3}}-C{{H}_{2}}-C{{H}_{2}}-\underset{C{{H}_{2}}C{{H}_{3}}}{\mathop{\underset{|}{\mathop{CH-\overset{C{{H}_{3}}}{\mathop{\overset{|}{\mathop{C}}\,}}\,H}}\,}}\,-C{{H}_{2}}C{{H}_{3}}}}\, $

Answer 1

Answer: (C)

$ C{{H}_{3}}-\overset{6}{\mathop{C}}\,{{H}_{2}}-\overset{5}{\mathop{C}}\,{{H}_{2}}-\underset{\,\,\,\,\,C{{H}_{2}}C{{H}_{3}}}{\mathop{\underset{|}{\mathop{\overset{4}{\mathop{C}}\,}}\,}}\,H-\overset{C{{H}_{3}}}{\mathop{\overset{3|}{\mathop{C}}\,}}\,H-\overset{2}{\mathop{C}}\,{{H}_{2}}-\overset{1}{\mathop{C}}\,{{H}_{3}} $
Correct IUPAC name is 4-ethyl-3-methyl heptane because substituents are written in alphabatical order.