1 Nomenclature Flashcards
Give the five steps for IUPAC naming of chemicals
- Identify the longest carbon chain containing the Highest order functional group (the parent chain)
- Number the chain
- The carbon numbered 1 will be the one closest to the highest-priority functional group
- The more oxidized (substituted) a carbon is, the higher priority it is.
- Name the substituents (functional groups)
- Will be placed at the beginning of the name as a suffix
- only the highest priority functional group will determine the suffix for the compound and must be part of the parent chain
- Assign a number to each substituent
- Multiple substituents of the same type will get both the di-, tri-, and tetra- prefixes that we have previously noted and also a carbon number designation - even if they are on the same carbon.
- Complete the name
- Names always begin with the names of the substituents in alphabetical order, witch each substituent preceded by its number.
- Note: Prefixes like di-, tri-, tetra- as well as hyphenated prefixes like n- (normal) and tert-/t- (e.g. like t-butyl) are ignored while alphabetizing.
- Nonhyphenated roots that are part of the name, however, are included: iso- (e.g. isobutyl), neo, or cycla etc.
- The numbers are separated from each other with commas and from words with hyphens.
- Finish the name with the name of the backbone chain, including the suffix for the functional group of highest priority.
Recall the structure for the following common alternative alkyl substituents
- t-butyl
- neopentyl
- isopropyl
- sec-butyl
- isobutyl
What are alkanes? Give their names depending on number of carbons.
- Simple hydrocarbon molecules with the formula CnH(2n+2)
- Methane
- Ethane
- Propane
- Butane
- Pentane
- Hexane
- Heptane
- Octane
- Nonane
- Decane
- Undecane
- Dodecane
How are alkyl halides named?
Halogens (fluorine, chlorine, bromine, and iodine) are common substituents on alkanes (methane, ethane, propane etc.)
Alkyl halides are indicated by a prefix: fluoro-, chloro-, bromo-, iodo-
What is the difference between alkanes, alkenes, and alkynes?
Alkanes: Hydrocarbons with no substituents
Alkenes: Double bonds present
Alkynes: Triple bonds present
How are alcohols named?
Replacing -e in the name of the corresponding alkane with -ol (e.g. methane to methanol)
- Chain is numbered so that the carbon attached to the hydroxyl group gets the lowest possible number.
What are diols (aka glycols)?
Alcohols with two hydroxyl groups are called diols or glycols and are indicated with the suffix -diol. The entire hydrocarbon name is preserved and -diol is added.
When naming diols, one must number each hydroxyl group. For example, ethane-1,2-diol is an ethane molecule that has a hdyroxyl group on each carbon. This molecule is also known by its common name, ethylene glycol.
What are geminal diols and vicinal diols?
Diols with hydroxyl groups on the same carbon are called geminal diols (hydrates). Hydrates are not commonly seen because they spontaneously dehydrate to produce carbonyl compounds with the functional group C=O
Diols with hydroxyl groups on adjacent carbons are called vicinal diols (think vicinity)
What are aldehydes and ketones?
molecules with carbonyl groups (C=O).
Aldehydes: carbonyl group is chain terminating on the parent chain
Ketons: carbonyl group is in middle of chains
Sugars are classified as either aldoses (aldehyde sugars) or ketoses (ketone sugars)
How are aldehydes named?
Replacing the -e of the parent alkane with the suffix -al (e.g. ethane to ethanal)
Usually a number doesn’t have to be used as the aldehyde functional group is the highest priority and therefore on the first carbon (you do not do 1-butanal for example)
How are ketones named?
By replacing the -e in the name of the parent alkane with the suffix -one (e.g. pentane to 2-propanone/acetone/dimethylketone)
In the case that there is a higher priority group that takes precedence over the carbonyl, we name aldehydes and ketons as substituents using the prefix oxo- (ketones may sometimes by indicated with prefix keto-)
The carbon adjacent (on either side) of the carbonyl carbon is alpha, the one next to that beta and so on. Alpha-carbon acidity is notable.
It is important to know both the common names and IUPAC names for common aldehydes and ketones. What are the structures and IUPAC names for the following aldehydes and ketones:
- Formaldehyde
- Acetaldehyde
- Acetone
- Formaldehyde (methanal)
- Acetaldehyde (ethanal)
- Acetone (2-propanone or dimethylketone)
How are carboxylic acids named?
-e in the name of the parent alkane is replaced with the suffix -oic acid.
Remember: carboxylic acid functional groups are always terminal and on the MCAT they are the most oxidized carbons and therefore that carbon will always be 1 (no need to number it though).
Recall the common names for the following carboxylic acids
- Methanoic acid
- Ethanoic acid
- Propanoic acid
- Methanoic acid: formic acid
- Ethanoic acid: acetic acid
- Propanoic acid: propionic acid
What are esters? How are they named?
Common carboxylic acid derivates where the hydroxyl group is replaced with an alkoxyl group (-OR, where R is a hydrocarbon chain).
Naming them is easy. The first part of the name is the alkyl name of the esterifying group (e.g. ethyl propanoate). The second part is the parent acid with -oate replacing the -oic acid suffix (e.g. ethyl propanoate).
Groups bonded directly to the ester oxygen are named as substituents and are not numbered.
What are amides and how do you name them?
The hydroxyl group is replaced by an amino gorup (nitrogen containing group). The amino nitrogen can be bonded to zero, one, or two alkyl groups.
Named similary to esters except the suffix is -amide. Substituents attached to the nitrogen atom are labeled with a captial N-, indicating that this group is bonded to the parent molecule via a nitrogen. These substituents are included as prefixes in the compound name and are not numbered.
What are anhydrides and how do you name them?
Carboxylic acid derivative. Formation of anhydrides is from two carboxylic acid molecules with a water molecule removed. Many are clyclic.
Named by replacing acid with anhydride in the name of the corresponding carboxylic acid if the anhydride is formed from only one type of carboxylic acid. If the anhydride is not symmetrical, both carboxylic acids are named (without the suffix acid) before anhydride is added to the name.
