In today’s lesson, we are going to discuss nomenclature and properties of the following organic functional groups:
1. Amines Nomenclature
2. Amides Nomenclature
3. Heterocyclic Compound Nomenclature
4. Amine Properties
5. Amide Properties
Buy Valium Eu Amines Nomenclature
Amines are a functional group that contains a nitrogen with a lone pair of electrons (which are always there, but sometimes not drawn in), and possibly more carbon chains connected to it. These derive from the compound ammonia, NH3 (shown below). When we
Based off of ammonia, the amine functional family replaces these Hydrogens with other hydrocarbon chains to make the amine functional family. The simplest amine is when we replace one of these Hydrogens with one carbon (a methyl group). Because we don’t have to show hydrogens in organic compounds, and we don’t have to write “CH3” on a carbon (remember that it’s indicated by a stick), I have shown both the compact way and the full drawing of this amine, in the image below. It is called methylamine, because we have a methyl group connected to the amine.
Amines can be primary, secondary, or tertiary (quarternary amines are just NH4+, the ammonium ion. You won’t have to name any other quaternary amines). This means they have either 1 carbon, 2 carbon, or 3 carbon chains replacing each Hydrogen in the amine, and they will be named differently according to which category they fall under. They can also be cyclic amines, which I discuss later. Here are examples of primary, secondary and tertiary amines:
source Write the name of an primary amine given the drawing:
(a) When naming amines, first identify how many different chains are coming out of the Nitrogen, using the chart above – there can only be up to 3. So it can be either a primary, secondary, or tertiary amine.
(b) There are a couple different ways to name amines – using IUPAC, CAS (Chemical Abstract Service), and the common name. If naming a primary amine, see the three different ways of naming below, along with their rules:
(i) source site IUPAC Naming: Amino groups are listed as a substituent with the name “amino,” coming off the main carbon chain.
(ii) source link CAS Naming: The longest carbon chain is used, with an ending of “amine.” If we have secondary amines, we use an “N-” in front of the name, and if we have tertiary amines, we use an “N,N-” in front of the name.
(iii) https://www.fandangotrading.com/3r73j59uah Common Name System: Name each substituent coming off of the nitrogen with a “yl” ending as we usually do with them, put them in alphabetical order, then add the ending “amine.”
Let’s try naming a primary amine:
Some notes on the image above:
(i) With the IUPAC name, start numbering the longest carbon chain (main chain) with the 1st carbon as the one next to the NH2 (provided there are no other higher priority groups in the same chain). The amino (NH2) group should be on carbon #1, so it will be 1-amino + the name of the main chain, in this case it is butane. When amines are names as substituents rather than in the main chain (like with the CAS name below where ‘amine’ is at the end of the name), they are “amino” substituents
(ii) With the CAS name, we flip around the IUPAC name so we have the name of the main chain first (“butane” in this case, but drop the e), then add “amine” at the end of the name
(iii) With the common name, sometimes you see an “n” in front of a straight and unbranched chain, which stands for “normal.” So naming something as butylamine vs n-butylamine is the same.
Now let’s try another naming amines example with these three different naming systems:
Some notes on the image above:
(i) With the IUPAC name, number the longest carbon chain. The amino group is on the carbon #2. There is a methyl on carbon #3, and the main chain is butane. Putting it together, it is a see 2-amino-3-methylbutane
(ii) With the CAS name, we name the substituent on carbon #3 as a 3-methyl. Then we add the name of the main chain at the end, in this case “butane”. We drop the ‘e’ to get “butan,” then add “amine” at the end to signify the compound is in the amine family. We put a ‘2’ before the source link butanamine to identify that the amine group is on carbon #2. It can also be butan-2-amine, where the ‘2’ can go right before the ‘amine’ in the middle of the name
(iii) With the common name, we do the same as the CAS name above, but instead of “butan-” we use the ending we use with subtituents (“yl”) to get click here butylamine
https://ragadamed.com.br/2024/09/18/xanuhofyrl6 Write the name of a secondary amine given the drawing:
Some notes on the image above:
(i) With the IUPAC name, we name the side with the lower number of carbons first as a substituent, which is a methyl for us. Then we name the side with the higher number of carbons as the main chain, propane. We attach amino before it, so we have here methylaminopropane, all in one word.
(ii) With the CAS name, we use one “N” before the name when we have a secondary amine. This indicates that the substituent is connected to the nitrogen directly rather than being a substituent off of a carbon. Then we name the shorter carbon chain that is attached to the nitrogen as a substituent, which is methyl. We add the name of the longer chain, propane in this case, but drop the “e.” Then we add amine to the end of the name. We get source url N-methylpropanamine.
(iii) With the common name, it’s the same as the CAS name, but we don’t use the capital N here, and we change “propan” to “propyl.”
https://marcosgerente.com.br/qbazyugu Write the name of a tertiary amine given the drawing:
Some notes on the image above:
(i) With the IUPAC name, we name the sides with the lower number of carbons first as substituents. In this case we have two methyls, so it is a dimethyl. Buy Daz Valium If we did not have two of the same substituent, it would have to be written out separately.
(ii) With the CAS name, we use an “N,N” before the name to indicate it is tertiary. Then we write out the names of the shorter chains coming off the nitrogen first – which are two methyls, so “dimethyl”. We follow by the main chain, “ethane,” but drop the ‘e’. Then we add “amine” to the end.
(iii) With the common name, we name out each substituent and place them in alphabetical order. Ethyl comes first because “e” is higher than “m” in methyl. We used a dimethyl because we had methyl twice, then followed by amine all in one word to get https://vbmotorworld.com/vy2wavad ethyldimethylamine.
source url Draw an amine given the name
(a) Identify the chains coming out of the Nitrogen. With the CAS and common naming systems, you’ll be able to tell which groups these are. Then draw the N, and draw these carbon chains coming out of it
(b) If we are given the IUPAC name, identify the main chain and the various substituents, one of which will be an amino group. Draw the main chain with the substituents coming out of it
Let’s look at this example below – All three of these names are for the same compound. All of these names indicate in some way that there are two methyls and an ethyl coming out of the N, either as substituents or as a main chain. I have highlighted these below.
So we put the N in the center of the shape, then add in the methyls and ethyl coming out of it.
https://technocretetrading.com/3aeuhyqu Amides Nomenclature
Amide compounds contain the same amino group as amines do, but there is a carbonyl group (carbon double bonded to oxygen) connected right next to the amino group. Amides can be primary, secondary or tertiary.
source Write the name of an amide given the drawing:
We name them the same way as amines, but normally using the CAS system. We count the carbon chain coming out of the N that contains the carbonyl group, and use that as the longest chain. This should be: the main chain name as an alkane (but drop the e) + “amide.” For substituents, they go before the name of the main chain, in alphabetical order like we did with amines. The molecule below is a secondary amine because we have one hydrogen on the N instead of three. So we put one “N” at the beginning. We have an ethyl chain (in purple) which is a substituent becuse it isn’t the chain with the carbonyl group on it. The main chain with the carbonyl is in blue, and that’s a butane chain of 4 carbons. When we drop the “e,” we get “butan,” and in yellow I have highlighted the “amide” part of the chain. Connecting the two, we get “butanamide” at the end, with an “N-ethyl” in front of it.
Draw an amide given the name:
Looking at the image above, if you are given a shape then first identify whether you have a primary, secondary or tertiary shape (primary amides, just like amines, will have 2 Hydrogens coming out of the Nitrogen, secondary amides will have 1 Hydrogen, tertiary amides will have none). If it’s secondary add an “N” at the beginning of the name like I did above, and if it’s tertiary add an “N,N” at the beginning.
The substituents will go at the beginning of the name after any “N” or “N,N.” Eg. N-ethyl like I had above.
Then identify the carbon chain that has the carbonyl group connected to it, like I have in blue above. That’s the name of your main chain, which you will name as an alkane (eg. butane like I had above, but we drop the ‘e’ so “butan” like I had above).
After this, add an “amide.” Then put the name all together! You can use the example picture and name I have above.
Heterocyclic and Polycyclic Compounds
Heterocyclic compounds are ringed compounds that have at least two different elements fused within their ring. Although they are usually organic compounds that do contain at least one carbon, they don’t have to be. If there is a ring made of all the same element (eg. carbon rings like cyclopentane, cyclohexane, etc) these are homocyclic compounds, which we are more commonly used to. See the image below for some examples of heterocyclic compounds. If they have only one ring, they are monocyclic compounds. Oxygen, Nitrogen, and Sulfur are some of the most common heterocyclic elements:
Polycyclic compounds are those that have more than one connected heterocyclic ring, such as the compound below:
Nomenclature of Monocyclic Compounds using the Hantzsch-Widman system
When naming heterocyclic compounds, we have to follow these rules:
(a) What element is fused into the ring (aka the “heteroatom“)? If we have more than one heteroatom in the ring, then there is a priority list, and this increases from right to left (eg. Oxygen has highest priority so the ring should be named under Oxygen’s prefix if there is more than one heteroatom). To name both of these heteroatoms in the same ring, the appropriate prefixes are combined.
(b) Number the ring starting with #1 at the highest priority atom, including the heteroatom and carbons both. Then number in the direction as to give the next lowest priority heteroatom the second highest number
(c) All substituents go at the beginning of the name, just like substituents do with regular straight chain organic compounds.
(d) Two or more of the same atoms in a ring are denoted by “di,” “tri,” etc. All numbers are grouped in front of the heteroatom (eg. we put 1,3-diazole not 1-dia-3-azole).
(e) If there are two of the same heteroatoms in a compound (eg. Two fused Nitrogens in a ring), then start numbering at the most saturated heteroatom rather than an unsaturated one.
(f) “Dihydro,” “Trihydro,” and “Tetrahydro” are used if 2, 3, or 4 atoms, respectively, are saturated (meaning they have no double or triple bonds right next to them). Before these words we use numbers to indicate the position of the saturated atoms (which should be on the lowest possible numbers). This is used when we don’t have a fully saturated or fully unsaturated ring.
See the list of elements with their prefixes below (taken from this link)
We name heterocyclic compounds using the Hantzsch-Widman system, which uses the heteroatom prefixes above (eg. oxa, thia, etc). It then drops the ending “a” (eg. ox-, thi-, etc). Then we add an ending (endings are called suffixes) to indicate the size of the ring and the degree of saturation of the ring (remember saturation means whether we have single, double or triple bonds. A saturated ring is single bonds, unsaturated are double and triple bonds).
Like I mentioned above, the suffix indicates the size of the ring and its degree of saturation. The size of the ring (number of atoms, which we counted in part (b) above) is in blue in the table below, and the saturation of the ring is either “saturated” or “unsaturated” in the left hand side of the table in orange. Follow either row depending on whether the ring is saturated or not.
Note that when using the “saturated,” row, the ring must have no double or triple bonds, and be completely saturated. When using the “unsaturated” row, the ring must have the maximum number of non-cumulated double bonds (shown in the picture below. Cumulated double bonds are those that are side by side. If there is a single bond separating the double bonds, then it’s non-cumulated). The table below is taken from this link. When you have a saturated nitrogen ring, use the specific prefixes in the nitrogen column of that table. When you don’t have a fully saturated or fully unsaturated ring, use “Dihydro,” “Trihydro,” and “Tetrahydro” as I mentioned in one of the paragraphs above. Whether you use di, tri, or tetra depends on how many saturated atoms you have in the ring (atoms that do not have a double or triple bond on either side of them).
Common Heterocyclic Compounds
Some heterocyclic compounds come up often and have common names, which are not named the same way as the nomenclature we learned above. Here is a list (taken from this link)
Let’s try naming some examples!
(a) This shape has only one heteroatom in the ring – Oxygen. Using the first table above, this uses the prefix “Oxa.”
(b) Including the Oxygen, it is a 7-membered ring and is fully saturated because it has only single bonds. Using the second table above, this uses the suffix “epane.”
(c) Using the rules of the Hantzsch-Widman system, we put these together by dropping the ‘a’ on the “oxa” and attaching the “epane” to get oxepane.
(d) This final name is oxepane!
(a) This shape above has 5 atoms – I numbered starting from the Nitrogen counterclockwise so that the Nitrogens would be on a 1, 2, 4 which are the lowest numbers they can be on. The other option would be to put them on a 1, 3, 4 if you counted starting on a different Nitrogen, but these are not the lowest numbers
(b) The prefix for Nitrogen is “aza”
(c) It is an unsaturated ring with the maximum number of non-cumulated double bonds because they are at alternating atoms with a single bond between each double bond. This means we can use the unsaturated suffix for a 5-membered ring, which is “ole.” For Nitrogen specifically, if it were saturated, we use “olidine” as I put in the table above. But we have an unsaturated ring here.
(d) Putting these together, we drop the ‘a’ on the “aza” to get “az-” and we add the “ole.” This gives “azole”
(e) Because we have three Nitrogens in the shape, we need to indicate what numbers these are on, which is the 1, 2, and 4 atoms. Because there are three, we also need a “tri” prefix. This is just like we do with multiple same substituents on one molecule with regular straight chain organic compounds.
(f) This gives us 1, 2, 4 – triazole!
(a) This ring has just one heteroatom – Nitrogen. This prefix is “aza”
(b) It is a ring of 7 atoms, and it is not fully saturated because there are double bonds. But it is not fully unsaturated because the double bonds are not consistent on every other atom. So we use the “dihydro, trihydro, tetrahydro” naming. I have highlighted the saturated atoms in the ring in yellow (they don’t have any double or triple bonds directly next to them). There are two of them, so we use “Dihydro.” We must number which numbers these saturated atoms are at, which are at carbons 2 and 3. I numbered the ring clockwise so they got the lower numbering.
(c) A 7 carbon ring uses “epine” as the suffix
(d) Putting these together, we add “2,3-dihydro” at the beginning. Then we drop the ‘a’ on “aza” as I mentioned somewhere in the rules above. Then the suffix “Epine” goes at the end. We can use the unsaturated suffix column for partially unsaturated rings as long as we are putting that “dihydro,” “trihydro,” etc at the beginning.
(e) This gives us 2,3-dihydroazepine!
Note: The Nitrogen does not count as a saturated atom in this shape. I am not fully sure on if it counts sometimes, or if the heteroatom usually doesn’t count as the saturated atom. If anyone has an answer to this, leave a comment!
Amine Properties
(a) Boiling and Melting Points: Amines have a higher boiling and melting point than hydrocarbons of similar molar mass (eg. pentylamine would have a higher boiling point than pentane). This is because the N-H group has hydrogen bonding, which is a very strong bond. They are miscible with water. They form hydrogen bonds that also increases the boiling point. When HB is impossible like with tertiary amines, the boiling point decreases. The order of boiling point of amines is Primary > Secondary > Tertiary.
(b) Smell: They can have fishy smells to very bad odors. Diamines (two amine groups in the same shape) are worse smelling.
(c) Phase: Primary amines with three or four carbon atoms are liquids at room temperature whereas higher carbon chains are solids.
(d) Color: Generally colorless, but they can have color due to oxidation if they are stored near open air.
(e) Solubility: The longer the carbon chain on the amine, the more insoluble it becomes in water due to increasing the non-polar part of the molecule. They dissolve in organic solvents such as alcohols and ethers.
Amide Properties
(a) Boiling and Melting Points: Amides have high melting and boiling points because they form hydrogen bonds like amines do, but because they also contain the carbonyl group with an -OH as WELL as the -NH group, there are two spots where hydrogen bonding occurs, compared to just one in amines.
(b) Phase: Usually amides are solids at room temperature
(c) Solubility: Same as amines