MCAT Organic Chemistry Review

Nomenclature

Answers to Concept Checks

· 1.1

1. 1. Find the longest carbon chain in the compound with the highest-order functional group; 2. Number the chain; 3. Name the substituents; 4. Assign a number to each substituent; 5. Complete the name

2.

Note: There are two possible answers; however, the longest chain must include the hydroxyl group.

3. Numbers are separated from each other by commas with no spaces. Numbers are separated from words within the compound name by hyphens.

· 1.2

1. 

2. Butane and all hydrocarbons that are larger than butane may have a branched appearance, which shortens the parent chain. An example is isobutane, properly named methylpropane, shown on the next page. Any branched hydrocarbon with the correct number of carbons and no multiple bonds or rings is correct.

3.

2. The alcohol would take precedence because the carbon to which it is attached has a higher oxidation state.

3. Diols are alcohols with two hydroxyl groups. For geminal diols, these are on the same carbon. For vicinal diols, they are in the vicinity of one another—on adjacent carbons.

4. Isopropyl alcohol and ethyl alcohol, respectively.

· 1.3

1. An aldehyde has a carbonyl group at the end of the chain. A ketone has a carbonyl group somewhere in the middle of the carbon chain. Another way to think of this is that the carbonyl carbon of an aldehyde has at least one bond to a hydrogen atom, whereas the carbonyl carbon of a ketone is always bound to two other carbons.

2. Aldehydes are referred to with the suffix –al, while ketones are given the suffix –one. Carbonyl groups of both aldehydes and ketones are labeled as oxo– substituents (ketones may also be called keto– substituents).

3. 

4. Ketones and aldehydes both take precedence over both alcohols and hydrocarbon chains, and the functional group that is the highest priority determines the suffix. Therefore, the aldehyde would determine the suffix when naming this compound.

· 1.4

1. The ester derivative would be methyl pentanoate. The amide would be pentanamide. The anhydride would be pentanoic anhydride.

2. 3-methyl-2-oxopentanoic acid