Amine naming 2
Amine naming 2. Created by Sal Khan.
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- What is the order according to higher priority among functional groups as substituents of the main carbon chain? Thanks.(14 votes)
- Cations > Carboxylic Acids > Sulfonic Acids > Acid Anhydrides > Esters > Acyl Halides > Amides > Imides > Nitriles > Aldehydes > Ketones > Alcohols > Thiols > Hydroperoxides > Amines > Ethers > Sulfides> Alkenes > Alkynes > Alkyl Halides > Nitroalkanes > Alkanes(52 votes)
- At @4:10Sal says that the amino group should be given priority over the others. Is there any rule to find out which functional group should be given priority?(7 votes)
- yes there is a preference table for finding that.
go to http://en.wikipedia.org/wiki/IUPAC_nomenclature_of_organic_chemistry(18 votes)
- Why can't you count benzene as part of the backbone chain so that it has 11 carbons?(12 votes)
- So, if in the first example, If i shortened the 8-chain ring to just 5-chains, would the compound be named based on that 5 carbon chain or based on the phenyl group since the phenyl group has more carbons?(5 votes)
- why does it matter about alphabitacle order for the compund(2 votes)
- I'd hate to look in a phonebook that's not arranged alphabetically...(23 votes)
- Why does the alcohol group take priority over the amino group?(2 votes)
- The IUPAC has defined a standard order of functional groups. Several factors go into making this list, but one is atomic number, Since O > N, alcohols have priority over amines. You can see a table of priorities at http://www.chem.ucalgary.ca/courses/350/Carey5th/useful/nomen.html(12 votes)
- what are the chemical reaction of amines??(5 votes)
- 1.)Aminolysis: ammonia or amines react with an aldehyde or ketone to form an amine. The reaction needs a reducing agent like NaBH4
Ex: NH3 + H2-C=O -> CH3NH2
2.) Hoffman Rearrangement: Amides react with Br2 and NaOH to produce an amine
Ex: CH3CONH2(acetamide) + NaOH +Br2 -> CH3NH2 + CO2
3.) Curtius Rearrangement: Similar with Hoffman Rearrangement but instead of Amides, Acid Chlorides react with NaN3(sodium azide) to form amines
Ex: CH3CH2CH2COCl(butanoyl chloride) + NaN3 + heat -> CH3CH2CH2NH3 + CO2
4.) Sandmeyer Reactions: Amine reacts with HNO2 and H2SO4 to produce a Diazonium salt which reacts with a lot of reagents
-with CuBr and HBr to form Bromobenzne(from Diazotization of aniline)
-with CuCl and Hcl to form Chlorobenzene(from Diazotization of aniline)
-with HCN and KCN to form Benzonitrile(from Diazotization of aniline)
-with Cu2O and CU(NO3)2 to form Phenol(from Diazotization of aniline)
-with H3PO2 to form Benzene(from Diazotization of aniline)
5.) Diazonium Coupling Reactions: ArylDiazonium salts react with activated aromatic rings, like Phenol, to produce azo compounds
Ex: (C6H5-NN)+HSO4- reacts with Phenol to form (C6H5)-N=N-(C6H5) <- an azo compound
6.) Hoffman Elimination: An amine reacts with Ag2O and an excess of CH3I to form alkenes through an anti-zaitsev process
Ex: 2-butylamine + CH3I + Ag2O + heat -> 1-butene
7.) Reactions of an aryl or alkyl halide to form amines: Alkyl/Aryl halides react with NaN3 and the reducing agent: LiAlH4, ether to form Amines
Ex: CH3CH2CH2Br + NaN3 -> CH3CH2CH2N=N=N + LiAlH4 and ether -> CH3CH2CH2NH2
Ex: Bromobenzne + NaN3 -> (C6H5)-N=N=N + LiAlH4 and ether -> Aniline - (C6H5)-NH2(4 votes)
- if benzene is just a functional group attached to a carbon compound it's prefix is 'phenyl'.similarly what is the prefix given to a cyclohexane if it is a functional group too?(3 votes)
- why does sal start numbering the first compound from the right?
should'nt he start from the left because then only the branched chains get the lowest numbering possible?(2 votes)
- The OH group takes priority over the others in the numbering.
So he has to start numbering from the end that is closest to the OH group — the right hand end.(5 votes)
- why are amines not acidic in nature? electronegativity of nitrogen and oxygen is almost same [ 3, 3.5] so the bond N - H and O - H must be almost identical ( with reference to polarity )(1 vote)
- You might be surprised at the big change in acidity a difference of 0.5 in electronegativity can make.
Here are the electronegativities of some atoms X and the pKₐ values of their X-H bonds.
C(2.55); pKₐ = 44
N(3.04); pKₐ =38
O(3.44); pKₐ =16
F(3.98); pKₐ =3
In the ionization X-H → X⁻ + H⁺, the main difference is in the stability of the X⁻ ion.
As the X atom becomes more electronegative, it is better able to stabilize the negative charge, so the position of equilibrium moves to the right.(6 votes)
I was wondering why its called 3-bromo-4-nitroaniline, and not 1-bromo-2nitroaniline?? I didnt think we could count the amine after we combined it with the benzen?(0 votes)
- The carbon containing the NH₂ group is automatically number 1.
You start counting from there.(7 votes)
Let's see if we can handle some slightly more difficult amine naming examples. So if we look at this blue molecule right here, we always want to start off by finding the longest carbon chain. It looks like it's this chain at the bottom where we have one, two, three, four, five, six, seven, eight carbons. So it's going to be octan. We don't want to just call it octane because we have these functional groups up here, and maybe one of them's going to take higher priority than just the fact that this is an alkane. And, in fact, one of them will. So let's look at them. So over here we an amino group. That would make this molecule an amine. So this is an amino group right here. Then we have this benzene ring. And when benzene is a functional group, we call it a phenyl group. And that's derived from I think it's either the Greek or the Latin word for light because benzene was first isolated from, I guess, the air around lanterns or something, so this is called a phenyl group. And then finally we have this OH, which would make this whole thing an alcohol, or we could call that a hydroxy group, so this right here is a hydroxy group. Now, this is just something that you need to know. There's no way to kind of deduce it. The people who've decided how to name things just decided that certain groups take higher priority over others. And out of these three groups, the hydroxy group, the thing that's making this whole thing an alcohol, takes the highest priority, so this is what's going to define the suffix. So if we start numbering, we want to start numbering this chain closest to the highest priority group. So we'll start numbering at this end. So it's one, two, three, four, five, six, seven, eight. So we have a hydroxy group on the three carbon, so this is octan-3-ol. If this was not a high priority, we would put a hydroxy in the front, but since this is the highest prioritiy, its defining this as an alcohol, octanol. But we put the 3 there to say it's on the three carbon. And then, of course, this would be 5-phenyl. This right here is 5-phenyl. And this right here is 8-amino. And amino comes before phenyl in alphabetical order, so this whole molecule is going to be-- let me write it over here-- it's going to be 8-amino-5-phenyl-octan-3-ol. And we're done. So this is an aromatic compound because of the benzene ring. It's an amine because of the amino group. And it's an alcohol because of the hydroxy group. Now let's look at this molecule here in green. And actually, I forgot to draw part of it. This is supposed to be a benzene ring. So let me make clear. That is a benzene ring. So let's think about the different functional groups here. And we'll start with the one that you've probably never seen before. This is a nitro group, and it's highly explosive. Maybe in a future video, I'll show you some nitroglycerin and some TNT, as you know, which are highly explosive, but they have nitro groups on them. So this right here is a nitro group. It takes very low precedence in the whole scheme of things. So this will never be the cause of naming the suffix. We just know that this is a nitro group right here. We, of course, have a bromo group that we've seen many times. That is a bromo group. And then we have an amino group right here. So this is going to be-- let me do this in a different color. This is definitely an amine. This is an amino group right there. And out of these three groups, the amino group is definitely of the highest priority. So you might be tempted to name this 1-amino-2,3-brom o-4-nitrobenzene, but when a benzene ring is attached to an amino group, this one also has one of those special names. And let me just do it on the side right here. So if I just have a benzene ring attached to an amino group, so that's an NH2 right there, we call this molecule right here, and this is just the common name for it and it's something to put in your toolkit, this is aniline. So that will be the base name. This whole thing right here we call aniline. Let me write it over here. So this is aniline. And then we always want to start numbering at the group that's really defining the molecules, so we start numbering here. And you want to go in the order where you're going to bump into something first. So, one, two, three, four. So this is going to be-- if we look at them, and bromo comes alphabetically before nitro, so it's going to be 3-bromo-4-nitroaniline. And we are done!