MCAT: Organic Chemistry: Nomenclature
Carbonyl
C=O
Carboxylic acid derivatives:
Esters, amides, anhydrides
Alcohols are often named by their common names
Ex: ethanol = ethly alcohol; isopropyl alcohol = 2-propanol
Name this structure
Hept-6-en-1-ol
Propanal is referred to by its common name,
Propionaldehyde
Functional group priority
(Oxidized C -> higher priority) - alkenes and alkanes are tied, except in a ring, where alkenes have higher priority
Carboxylic acids
- COOH (carbonyl (C=O) + hydroxyl (-OH) - terminal functional groups ALWAYS on C1 - highest priority functional group - replace -e with -oic acid
naming relative to carbonyl group
- alpha carbons are adjacent to carbonyl carbon - successively distant carbons are beta, gamma, and delta carbons (ABGD)
Anhydrides
- carboxylic acid derivative - 2 carboxylic acid - 1 H20 - looks like a very excited party guy - named by replacing "acid" with "anhydride" if symmetrical - if asymmetrical, both carboxylic acids are named before "anhydride"
Amides
- carboxylic acid derivative in which -OH is replaced by N - -e is replaced with -amide - N- indicates substituents attached to N atom
Esters
- carboxylic acid derivative in which -OH is replaced with -OR (alkoxy group) (at least one alkyl on O) First name: alkyl hanging off of single bound O of ester, distal to the C=O Last name: parent acid name with -oate at the end (instead of -oic acid); C of carbonyl is included
-yne
triple bond
Form- prefix
Prefix shared by common names of methanoic acid (formic acid) (carboxylic acid) and methanal (formaldehyde) (aldehyde) - basically means meth i think
n-propyl
"Normal" straight chain alkane
Ketone
- numbered - carbonyl group not on the end - replace -e with -one - use oxo- if not highest priority (sometimes keto-) Above alcohol, below ketone
Acetone
- smallest ketone - acet-, like eth-, refers to 2 carbons, even though this compound has three carbons
t-butyl (tert-butyl)
-C(CH3)3
Steps to IUPAC nomenclature
1. Find longest carbon chain containing highest priority functional group. 2. Number the chain such that the HP functional group (gives suffix) has the smallest possible number. 3. Name substituents with a prefix and their number (add di-, tri-,... for multiples) 4. Alphabetize the prefixes and separate number and words with commas/hyphens
Name this structure
3-methyl-2-oxopentanoic acid
Ethanal is referred to by its common name,
Acetaldehyde
Leaving group
Atoms that can dissociate to form a stable species after accepting electron pairs.
Acetyl
COCH3 Ketone specifically 1 C away from the end Acet = carbons
Aldehyde
Carbonyl at end of chain (chain-terminating) - usually on C1, so don't need 1- - replace -e with -al - aldehydes and ketones do not have any leaving groups connected to carbonyl carbon - use oxo- if not highest priority Above ketone and alcohol
Phen- prefix
Derived from benzene
-ene
Double bond
Methanal is referred to by its common name,
Formaldehyde
Vicinial diols
Hydroxyl (OH-) groups on adjacent C's
germinal diols
Hydroxyl (OH-) groups on the same C - aka hydrates - uncommon because they spontaneously dehydrate (expel an H2O molecule) and produce carbonyls (C=O)
Know common and IUPAC name
IUPAC: ethanoic acid Common: acetic acid
Know common and IUPAC name
IUPAC: methanoic acid Common name: formic acid
Alcohol Naming
If highest functional group, replace -e with -ol (usually the case) If not highest functional group, hydrox-
Formic acid is a common name for
Methanoic acid (carboxylic acid)
Methyl formate is the common name for
Methyl methanoate (ester)
Are di-, tri-, tetra-, etc. used in alphabetization?
No
Are hyphenated prefixes like n- and tert- included in alohabetization? (Ex: n-propyl, tert-butyl)
No
Carboxyl
O=C-OH ox = OH
Are nonhyphenated roots like iso, neo, and cyclo included in alphabetization?
Yes
diols/glycols
alcohols with two hydroxyl groups Ex: ethane-1,2-diol (aka 1,2-ethanediol; common name: ethylene glycol)
Acetic anhydride is the common name for
ethanoic anhydride (anhydride)
carbon chain substituents
suffix -yl
