Naming Thiols: Study with Video Lessons, Practice Problems & Examples

Thiols, or mercaptans, contain a mercapto group (–SH) attached to a carbon atom. Their naming conventions resemble those of alcohols, where "thiol" is added to the parent chain name. The structure includes the location of substituents followed by the parent name. Understanding thiols is essential in organic chemistry, particularly in reactions involving functional groups like aldehydes and ketones, and their role in biochemical processes such as alcoholic fermentation and enzyme activation.

Rules for Naming Thiols Concept 1

Here we're going to say that thiols, also called mercaptans, possess a mercapto group. "Mercapto" just means SH group, connected to a carbon atom. Now the set of rules for naming thiols is very similar to the ones used to name alcohols. Here, all we do is add "thiol" to the parent chain name. So our naming convention will be the location of our different substituents, then we have the location and then the parent, and then our final name. Right? This is the way we would approach naming different types of files.

Naming Thiols Example 1

Name the following thiol compound. Right. So step 1 says to find the longest carbon chain because it'll represent the parent chain, and assign a name according to the prefixes. Now, the parent chain should include the SH group, the mercapto group, and have the largest number of carbons. If there is a tie between the longest chain, choose the chain with more substituents. If we take a look here, our longest chain would have to be this chain. Now we have our longest chain, so we have to, let's see, assign names according to the prefix. We're going to assign names to all the substituents here. So we know that this SH group is going to become a thiol. It's going to form near the end of the name, so we won't worry about it yet. We have "br" here, which is bromo, and one carbon here is methyl.

Step 3 is we start numbering the chain from the end closest to the SH group. So the end close to the SH group is here: 1, 2, 3, 4, 5, 6. If there's a tie, number from the end closest to the next substituent. If it's still a tie, number in alphabetical order. Assign the numerical location to the carbon with the SH group, which we did. And then steps 4 to 6 will repeat steps from previous naming topics. So here this is what it would look like. Alright, so we'd say we have bromo and methyl. We name those alphabetically. So bromo is on 3, so 3-bromo. 5-methyl. Then we're going to say that the thiol group, the mercapto group, is on carbon 2, so 2. It's a 6-carbon chain, so hexanethiol. Okay? So this would be the name of this particular thiol compound.

Determine IUPAC name for given compound.

• A. 1,2-hexenedithiol
• B. 5,6-hexanedithiol
• C. 5,6-heptanedithiol
• D. 1,2-hexanedithiol

Determine IUPAC name for given compound.

• A. 3-heptene-3-isopropyl-2-thiol
• B. 3-isobutyl-4-heptene-2-thiol
• C. 3-isopropyl-3-heptene-2-thiol
• D. 4-heptene-3-isobutyl-2-thiol

Draw skeletal structural formula for 2-ethylcyclopentanethiol.

• A.
• B.
• C.
• D.

Here’s what students ask on this topic:

What are thiols and how are they named?

Thiols, also known as mercaptans, are organic compounds that contain a mercapto group (–SH) attached to a carbon atom. The naming conventions for thiols are similar to those for alcohols. To name a thiol, you add the suffix 'thiol' to the parent chain name. The structure includes the location of substituents followed by the parent name and then 'thiol'. For example, if the SH group is attached to the second carbon of a propane chain, it would be named 2-propanethiol.

How do you differentiate between thiols and alcohols in naming?

While both thiols and alcohols have similar naming conventions, the key difference lies in the functional group. Alcohols contain a hydroxyl group (–OH), whereas thiols contain a mercapto group (–SH). In naming, alcohols use the suffix 'ol' (e.g., ethanol), while thiols use the suffix 'thiol' (e.g., ethanethiol). The position of the functional group is indicated by a number, and the rest of the naming follows the standard IUPAC rules for organic compounds.

What is the significance of thiols in biochemical processes?

Thiols play a crucial role in various biochemical processes. They are involved in the formation of disulfide bonds, which are important for the structural stability of proteins. Thiols also participate in redox reactions, acting as antioxidants. In metabolic pathways, thiols are essential in enzyme activation and in processes like alcoholic fermentation. Their ability to form strong bonds with heavy metals makes them important in detoxification processes as well.

Can you provide an example of naming a thiol with multiple substituents?

Sure! Let's consider a thiol with the molecular structure CH₃-CH(SH)-CH₂-CH₃. Here, the SH group is attached to the second carbon of a butane chain. Additionally, if there is a methyl group attached to the third carbon, the compound would be named 3-methyl-2-butanethiol. The numbering ensures the lowest possible locants for the substituents and the thiol group.

What are some common uses of thiols in industry?

Thiols are widely used in various industries due to their unique properties. In the petroleum industry, they are used as odorants for natural gas to detect leaks. Thiols are also used in the production of certain pharmaceuticals and agrochemicals. In the rubber industry, they act as vulcanization agents. Additionally, thiols are used in the synthesis of polymers and as intermediates in organic synthesis.