Nomenclature and Isomerism Flashcards

Comprehensive vocabulary flashcards covering organic nomenclature rules, functional group suffixes, types of isomerism, chirality, and pharmaceutical applications of optical isomers.

IUPAC Systematic Naming System

A naming system for organic chemistry based on a root describing the carbon chain length, with numbers (locants) and prefixes/suffixes indicating functional group locations.

Root

The part of an IUPAC name that describes the length of the longest unbranched carbon chain.

Cyclo-

A prefix used to indicate that hydrocarbon molecules form a ring structure, such as in cyclohexane ($C_6H_{12}$).

Alkenes

A family of organic compounds containing a $C=C$ bond, identified by the suffix -ene (e.g., propene, $CH_3CHCH_2$).

Alkynes

A family of organic compounds containing a $C\equiv C$ bond, identified by the suffix -yne (e.g., propyne, $CH_3CCH$).

Halogenoalkanes

Organic compounds containing a halogen ($F$, $Cl$, $Br$, or $I$), identified by the prefixes fluoro-, chloro-, bromo-, or iodo-.

Carboxylic acids

Compounds containing the $-COOH$ group, identified by the suffix -oic acid (e.g., ethanoic acid, $CH_3COOH$).

Anhydrides

Compounds with the formula $RCOOCOR$, identified by the suffix -anhydride.

Esters

Compounds with the formula $RCOOR'$ named from their parent alcohol and acid, using the suffix -oate (e.g., propyl ethanoate).

Acyl chlorides

Compounds containing the $-COCl$ group, identified by the suffix -oyl chloride.

Amides

Compounds containing the $-CONH_2$ group, identified by the suffix -amide.

Nitriles

Compounds containing the $RC\equiv N$ group, identified by the suffix -nitrile (e.g., ethanenitrile).

Aldehydes

Compounds containing the $-CHO$ group at the end of a chain, identified by the suffix -al.

Ketones

Compounds containing the $C=O$ group within a chain, identified by the suffix -one (e.g., propanone).

Alcohols

Compounds containing the $-OH$ group, identified by the suffix -ol or the prefix hydroxy- if other higher-priority groups are present.

Amines

Compounds containing the $-NH_2$ group, identified by the suffix -amine or the prefix amino-.

Arenes

A family of aromatic compounds, such as methylbenzene ($CH_3C_6H_5$).

Isomers

Compounds that have the same molecular formula but different molecular structures or a different arrangement of atoms in space.

Structural Isomers

Molecules with the same molecular formula but with different functional groups, different positions of functional groups, or different carbon skeletons.

Stereoisomerism

A form of isomerism where two or more compounds have the same structural formula but differ in the arrangement of their bonds in space; includes E-Z and optical isomerism.

Optical Isomers

Isomers that occur when four different substituents are attached to one carbon atom, resulting in non-superimposable mirror images.

Chiral Centre (Asymmetric Carbon Atom)

A carbon atom bonded to four different groups, often indicated by an asterisk (*), making the molecule chiral.

Enantiomers

A pair of optical isomers that are non-superimposable mirror images of each other.

Plane-polarised Light

Light waves that vibrate in only one plane after passing through a polaroid filter.

Polarimeter

A device used to measure the angle and direction of rotation of the plane of polarisation by different optical isomers.

(+)-isomer

The optical isomer that rotates the plane of polarisation clockwise.

(-)-isomer

The optical isomer that rotates the plane of polarisation anticlockwise.

Racemic Mixture (Racemate)

A $50:50$ mixture of two enantiomers that is not optically active because the rotational effects of the two isomers cancel out.

Nucleophilic Addition

A reaction type, such as adding $HCN$ across a $C=O$ bond, which can produce a racemic mixture if the starting material is planar.

$$109.5^{\circ}$$

The standard bond angle for a tetrahedral arrangement of groups around a central carbon atom in optical isomers.

Glycine (Aminoethanoic acid)

The only $\alpha$-amino acid that does not have a chiral centre.

Lactic Acid (2-hydroxypropanoic acid)

A chiral molecule produced naturally in sour milk or muscle tissue, which can be synthesised as a racemate from ethanal and $HCN$.

Ibuprofen

A common painkiller sold as a racemic mixture; the S+ form is an active anti-inflammatory, while an enzyme in the body converts $60\%$ of the R- form into the S+ form.

Naproxen

A drug where one optical isomer treats arthritic pain while the other causes liver poisoning, making it vital to sell only the effective isomer.

Thalidomide

A drug formerly used for morning sickness; its S-form caused serious birth defects, while the R-form acted as a sedative.