Quick questions on IUPAC nomenclature for organic compounds explained: HSC Chemistry Module 7

Alcohols, aldehydes, ketones, amines, alkenes, alkynes all take a locant before the suffix: butan-2-ol, pent-2-ene, hex-3-yne, butan-2-one, butan-2-amine. Aldehydes and carboxylic acids do not need a locant because they are always C1.

Esters are named alkyl alkanoate in two words.

A primary amine $R-NH_2$ takes the suffix $-amine$ with a locant for the nitrogen-bearing carbon. Secondary and tertiary amines are named by the largest parent amine, with the other substituents named with the $N-$ locant prefix. Example: $CH_3 - N(CH_3) - CH_2CH_3$ is $N,N$-dimethylethanamine (parent is ethanamine, two methyls on nitrogen).

When two numbering directions are possible, choose the one that gives the lowest locant to the principal group. If the principal group has the same locant in both directions, choose the direction that gives the lowest locants to the substituents, taken as a set (compare term by term).

Halogens are $fluoro$, $chloro$, $bromo$, $iodo$. Alkyl groups are $methyl$, $ethyl$, $propyl$, etc. An $-OH$ becomes a $hydroxy-$ prefix only when not the principal group (e.g. in 2-hydroxypropanoic acid, where the acid outranks the alcohol).

Alkyl (from alcohol) is named first, alkanoate (from acid) second. The alkanoate carbons include the carbonyl.

Apply IUPAC rules to name each structure: (a) $CH_3CH_2CH=CH_2$, (b) $CH_3CH(OH)CH_2CH_3$, (c) $HCOOCH_2CH_3$. [3 marks]

Draw the structural formula and write the molecular formula for 3-methylpentan-2-ol. [3 marks]

Provide IUPAC names for: (a) the addition product of HBr with prop-1-ene (Markovnikov); (b) the ester from propanoic acid and butan-1-ol; (c) the primary amine derived from propan-1-ol by direct ammonia substitution. [2+2+2 marks]