Question

Could someone please tell me the IUPAC name for these?

I'M SORRY about the side ways picture, I've tried everything to get it straight.

Answer 1

(a) `cis"-1,4-dipropylcyclohexane"`; (b) `trans"-1,3-diethylcyclopentane"`

I reproduced parts of your question below to make them more readable.

The compounds are both saturated cyclic hydrocarbons, so their class name begins with cyclo- and ends with -ane.

They are `color(blue)("cyclo")"alk"color(blue)("anes")`.

(a) Name the first compound

(i) Count the number of carbon atoms in the ring.

There are six carbon atoms. The numerical prefix for "six" is hex-. The name becomes cyclohexane.

(ii) Number the carbon atoms in the ring

One substituent is automatically `"C1"`.

Then number the other carbon atoms, taking the shortest path to the next substituent.

The substituents are on `"C1"` and `"C4"`.

(iii) Name the substituents

The substituents each have three carbon atoms.

The name of a carbon chain ends in -yl, and the numerical prefix for a three-carbon chain is prop-.

Each sidechain is a propyl group. The name becomes propylcyclohexane.

(iv) Indicate the numbers of each sidechain by a multiplying prefix.

There are two propyl groups, and the multiplying prefix for "two" is di-

The name becomes dipropylcyclohexane.

(v) Attach the numbers if the locants (the locating carbon numbers), separated from each other by commas and from letters by hyphens

The groups are on `"C1"` and `"C4"`, so the name becomes 1,4-dipropylcyclohexane.

(vi) Identify the cis-trans relationship of the groups

Both groups are "on top" of the ring — they are on the same side of the ring. The prefix for "same side" is cis-.

The complete name becomes `cis"-1,4-dipropylcyclohexane"`.

(b). Use the above principles to name the second compound

(i) Five carbon atoms in a ring → cyclopentane

(ii) Substituents on atoms 1 and 3.

(iii) Two-carbon chains → ethyl → ethylcyclopentane

(iv) Two ethyl groups → diethylcyclopentane

(v) Add locants → 1.3-diethylcyclopentane

(vi) Add stereochemistry

One group is "on top" of the ring, and the other is "on the bottom." The prefix for "on opposite sides" is trans-.

The complete name becomes `trans"-1,3-diethylcyclopentane"`.