# Write a condensed structural formula for each of the following?

## a) 3,4-diethylheptane b) 4-isopropyl-3methyldecane

Feb 9, 2017

${H}_{3} C - C {H}_{2} C H \left(C {H}_{2} C {H}_{3}\right) C H \left(C {H}_{2} C {H}_{3}\right) C {H}_{2} C {H}_{2} C {H}_{3}$

#### Explanation:

In both this case and the next, first we draw the longest chain, a heptane chain, and then appropriately substitute it.

For $\text{3-methyl-4-isopropyldecane}$, which is not strictly a IUPAC name, but would be understood, we do the same thing:

${H}_{3} C - C {H}_{2} C \text{*"H_2C"*} {H}_{2} C {H}_{2} C {H}_{2} C {H}_{2} C {H}_{2} C {H}_{2} C {H}_{3}$, to give the parent molecule, $\text{decane}$, and then substitute with alkyls at the starred carbons:

${H}_{3} C - C {H}_{2} C \text{*"H(CH_3)C"*} H \left({C}_{3} {H}_{7}\right) {C}_{6} {H}_{13}$.

This is one instance where it is easier to draw the beast out on paper rather pfaff around with an editor. Certainly you have to practise the representation of organic molecules on paper, so that you can show the examiner that you appreciate the connectivity of a given, named molecule.