Now, there's two ways to differentiate this. One is the common naming and one is the systematic naming. So let me differentiate between the two. So in the common naming, and this can get a little bit involved, and this frankly is probably the most complicated part of naming organic compounds.
Systematic is often more complicated, but it's easier to systematically come up with it. So there's a common and then there's a systematic. So the common way of doing it is, if you just say butylcyclopentane, that implies that you are bonding to the first or, depending on how you view it, the last carbon in the chain.
So this right here is butylcyclopentane. This right here is not just butylcyclopentane. What you would do is you definitely have a cyclopentane ring, so this would definitely be a cyclopentane. Let me put some space here. This is definitely going to be a cyclopentane. And you do have a butyl group on it, so we do have a butyl group, but because we are bonded-- we aren't bonded to the first carbon. We're bonded to a carbon that is bonded to two other carbons.
We call this sec-butylcyclopentane, so this is sec-. And everything I'm doing is obviously free-hand. If you were to see this in a book, the sec- would be italicized, or sometimes it would be written as s-butylcyclopentane. And this sec- means that we have attached to a carbon that is touching two other carbons. So you look at the butyl group, and say, well, which of these carbons is attached to two others? It's either that one or that one. And regardless of whether you're attached to this or this, if you think about it, it's fundamentally the same molecular structure.
So that's what you do when you're attached to that guy right over there. But what about the situation where we're dealing with just the common names right here? What about the situation where it looks like this? So we have our cyclopentane right there, and we have a-- I guess we could call it a butyl group. It'll have four carbons in it, but let's say that the four carbons look something like this.
Let's say there are four carbons, so we have one, two, three, four carbons and we're bonded to this one right over here. So whenever you're bonded to one end of the four-carbon group and it branches off at the other end, and it seems a little complicated, this only deals for alkyl groups below five or six carbons, this we call an isobutyl group.
So let me write this down. So this right here, is sec-butyl, or s-butyl sometimes for short. This right here, this right there is iso-butyl. It's actually-- iso- that is an iso-butyl group. And then the last thing to worry about when you're dealing with butyl groups is something like this. Let me draw it. So you could also draw four carbons like this. You have one carbon, two, three, four.
One, two, three, four carbons and you're attached over here. Now this naming, this group right here-- and you're going see the systematic naming is much easier for these compounds. This group right here, over here the carbon you're attached to is attached to two other carbons, so it is sec-butyl. When you're attached to three carbons, it is t-butyl, or tert-butyl, so this right here is a tert-butyl group, or sometimes called a t-butyl. And I really want you to understand the difference here.
The common naming, it's easier to say and easier to spell, but it's sometimes a little confusing. This is just straight up butyl so you would call this butylcyclopentane.
This is sec-butyl, because you have this guy connected to two carbons. That's where the sec- comes from. Sometimes it'll be s-butyl. So this could be called sec-butylcyclopentane or s-butylcyclopentane. This, because we're attached to the end away from this branching off, is still a butyl group, since we have four carbons.
But since we're attached here, this is iso-butyl, so this is iso-butylcyclopentane, And then finally, since the carbon we're attaching to is attached to one, two, three other carbons, it is a tert-butyl or a t-butyl group.
So this is t-butylcyclopentane. That's the common naming. So maybe I should clear out systematic here just so it's clear to you that everything we've done here is common naming.
So let me write it down. It won't hurt to write them down again because the more familiar you are with these, the better. So this is just butylcyclopentane. This is s- or sec- butylcyclopentane. And this is iso-butylcyclopentane. I'm going off the screen here. And then finally, this is tert-butyl, or t-butylcyclopentane. Now, I said these are the common naming. The prefix "iso" from "isomer" means "equal" while the prefix 'n-' stands for "normal".
An empirical formula consists of symbols representing elements in a compound, such as Na for sodium and Cl for chlorine, and subscripts indicating the relative number of atoms of each constituent element. Prefix neo is used for those alkanes in which two methyl groups are attached to the next to end carbon atom second last of the continuous chain. Iso - it means there is one methyl group on secondary carbon, neo - it means that there are two methyl groups on secondary carbon atom.
Bonding R to the carbon 1 of isobutane yields isobutyl. It's on the first carbon and this carbon has 1 other carbon attached to it so can we call it "n- isobutyl "? Alkyl group. Definition: An alkyl is a functional group of an organic chemical that contains only carbon and hydrogen atoms, which are arranged in a chain. Examples include methyl CH 3 derived from methane and butyl C 2 H 5 derived from butane. These rules get complicated, but we've tried to simplify them using 6 steps: Locate the longest carbon chain in our compound.
Name that parent chain find the root word Figure out the ending. Number your carbon atoms. Name the side groups. Put the side groups in alphabetical order. Esters can be named using a few steps Esters are named as if the alkyl chain from the alcohol is a substituent. No number is assigned to this alkyl chain. This is followed by the name of the parent chain from the carboxylic acid part of the ester with an —e remove and replaced with the ending —oate.
Seems to me that " isopropyl " should come before " methyl ," as the letter "i" is most definitely before the letter "m" in the alphabet. A systematic name is a name given in a systematic way to one unique group, organism, object or chemical substance, out of a specific population or collection.
When you have the prefix neo - you're talking about a compound in which all but two carbons form a continuous chain, and these two carbons are part of a terminal tert-butyl group.
The prefix iso -, which stands for isomer, is commonly given to 2-methyl alkanes. In other words, if there is methyl group located on the second carbon of a carbon chain, we can use the prefix iso -. The prefix will be placed in front of the alkane name that indicates the total number of carbons. Illustrated Glossary of Organic Chemistry - Isobutyl group. Isobutyl isobutyl group : A portion of a molecular structure equivalent to isobutane 2-methylpropane minus one hydrogen atom from carbon one.
Bonding R to the carbon 1 of isobutane yields isobutyl. It's on the first carbon and this carbon has 1 other carbon attached to it so can we call it "n- isobutyl "? Esters can be named using a few steps Esters are named as if the alkyl chain from the alcohol is a substituent. No number is assigned to this alkyl chain. This is followed by the name of the parent chain from the carboxylic acid part of the ester with an —e remove and replaced with the ending —oate.
Four carbon atoms but- and chiral. Tert-butyl is not called neo-butyl because the 'neo' form has two carbon branches as substituents on the main branch. In isopropyl functional group is attached to 2nd position, so basically isopropyl is 2-propyl. Whereas butyl group have 4 carbon atoms.
The key difference between isopentane and neopentane is that isopentane contains a four-membered carbon chain with one methyl group attached to this chain at the second carbon atom of the chain whereas neopentane contains one carbon centre attached with four methyl groups.
Sec - propyl does not exist, the smallest sec - substituent is sec -butyl. If you apply the meaning of " sec " to draw sec - propyl , you will see that it is exactly the same as isopropyl , the preferred name. The prefix " iso " is used when all carbons except one form a continuous chain. This one carbon is part of an isopropyl group at the end of the chain.
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