MCAT Organic Chemistry - Nomenclature

International Union of Pure and Applied Chemistry (IUPAC)

simplies chemical naming; unambiguous relationship between the name and structure of a compound; no two compounds have the same name

parent chain

Longest Carbon Chain Containing the Highest-Order Functional Group

Numbering

highest priority functional group/substituted carbons with the lowest number; assign substituents the number of carbon they are attached to

heteroatoms

atoms besides carbon and hydrogen, like oxygen, nitrogen, phosphorus, or halogens

Substituents

functional groups that are not part of the parent chain; assign the number of carbon they are attached to; numeric and hyphenated prefixes are ignored while alphabetising

carbon chain substituents

end with -yl

n- means normal

multiple - prefixes di-, tri-, tetra-, etc. directly before substituents

Alkanes

simple hydrocarbon molecules with the formula C_nH_(2n+2); saturated - only single bonds

name is the Greek root describing the number of carbons followed by –ane

Alkyl halides

indicated by a prefix: fluoro–, chloro–, bromo–, or iodo–; number the carbon

alkenes

simple hydrocarbon molecules with the formula C_nH_2n; unsaturated - at least one double bond

ends with -ene; number starting carbon of bond before parent or before suffix; number of multiple bonds prefix added to suffix

alkynes

simple hydrocarbon molecules with the formula C_nH(_2n-2); unsaturated - at least one triple bond

end with -yne; number starting carbon of bond before parent or before suffix; number of multiple bonds prefix added to suffix

Alcohol/hydroxyl group

―OH

ends with alykl parent suffix - e + ol; higher priority than alkyl chains - number each before suffix; if no priority, hydroxy- substituent; often have common names - name of alkyl group + alcohol

diol/glycol

alcohol with two hydroxyl groups

entire hydrocarbon + -diol; number each hydroxyl group

geminal diols/hydrates

diols with hydroxyl groups on the same carbon

not commonly seen because they spontaneously dehydrate to produce carbonyl compounds

vicinal diols

diols with hydroxyl groups on adjacent carbon

carbonyl group

―C=O

chain-terminating substituents

appear in the end of carbon chains

Aldehyde

carbonyl group found at the end of the carbon chain

parent alkane - e + al; do not include number if on carbon 1; if not priority, oxo- prefix

common names: formaldehyde; acetaldehyde; propionaldehyde

aldose sugars

Ketone

carbonyl group somewhere in the middle of the carbon chain

parent alkane - e + al; always include number; also alkyl groups in alphabetical order + ketone, if not priority, oxo-/keto- prefix

common names; acetone (2-propanone; smallest ketone)

ketose sugars

carbon names adjacent to carbonyl

adjacent to the

carbonyl carbon is indicated by alpha (α), then beta (β), gamma (γ), and delta (δ)

both sides of ketone

Carboxylic (organic) acids/carboxyl group

contain both a carbonyl group (C=O) and a hydroxyl group (―OH) on a terminal carbon; also written (COOH); highest priority functional group

parent alkane - e + -oic acid

common names: formic acid, acetic acid, propionic acid

Esters

COOR; hydroxyl group is replaced with an alkoxy group

name of parent acid - -oic acid + -oate; if not priority, alkoxycarbonyl- prefix

aloxy group

-OR, where R is a hydrocarbon chain

amide

CONR, hydroxyl group is replaced by an amino group; complex—the amino nitrogen can be bonded to zero, one, or two alkyl groups

name of parent acid - -oic acid + -amide; substituents attached to nitrogen are labeled with N-; if not priority; carbamoyl-/amido- prefix

amino group

a substituent group containing nitrogen

anhydride

In the formation of an anhydride from two carboxylic acid molecules, one water molecule is removed; symmetric if 2 same acid, asymmetric if 2 different acids; cyclic if intramolecular reaction of dicarboxylic acid

name of parent acid - acid + anhydride

Order of priority

Carboxylic acid > anhydride > ester > amide > aldehyde > ketone > alcohol > alkene or alkyne > alkane