Hello, good day! We continue with our study of organic chemistry. Today we're going to study the topic of alcohols. The activity we're going to do today is to name the following structures, and we'll start with our structure from part a. As you know, the first thing to do is identify the longest chain that contains the hydroxyl functional group, which is the H, located, as you can see, in the lower right corner. Okay, in this case, we have two options. First, we'll look at the option that is incorrect, and then the correct option. We'll explain why one is correct and the other is not. Let's begin with the incorrect option. In this case, it would be this carbon chain. Okay, this is the correct one. Next, we'll number the carbons. Remember that you number from the end closest to the hydroxyl functional group. In this case, it would be carbons 1, 2, 3, 4, 5, 6, and 7. So, a hydrocarbon chain of 7 carbons, except that since it doesn't have a hydroxyl functional group, the ending -al is added. So, it would be ethanol, 7 carbons. It's very important to mention here that The numbering starts from the carbons; the hydroxyl group is not counted, or should not be counted, as this is a very common mistake made by those beginning their study of organic chemistry of alcohols. Now we are going to analyze the correct option. The correct option, which we will mark in blue, is this option: a chain that twists to the right. Again, we identify the ends: in this case, the upper right end and the lower right end. As we can see, the hydroxyl functional group is closer to the lower right end; therefore, the numbering starts from that end. So it is carbon 1, 2, 3, 4, 5, 6, 7, and 8. In this case, the hydrocarbon chain has 8 carbons, so it is octane. This one does not have the hydroxyl functional group; the ending "-o" is added, so it is octane. And from there, we have to see, once we have identified the main chain, if this hydrocarbon structure has any branches or substructure. As you can see here in yellow, we are circling it, and if there is a branch, this branch, as you can see, has three carbons. Therefore, The three-carbon branch, as we recall, is called a proper branch, so we begin naming our structure. First, we name the branch; in this case, there is only one, and it is on carbon 4, so it is 4-hyphen- propel. And remember that between a name and a number, or between two names, there is a difference that must be marked by a hyphen. Between the number and the number, there is a difference that must be marked by commas, so that when we provide or generate the name, there will be no empty spaces. So it is 4-propel. Now we are going to indicate, we are going to name the main chain. We indicate the carbon number where the hydroxyl functional group is located; this is on carbon number 1. And from there we continue naming the main chain. The main chain, as we said, is an 8-carbon hydrocarbon chain with a hydroxyl functional group, so it is called octane, and that is our first structure. Now we analyze our second hydrocarbon structure. Again, what we are going to do now is identify the trunk or main chain. Remember, this trunk/main chain is the longest hydrocarbon chain. which has more carbons and in this case has the characteristic that it must integrate all the hydroxyl functional groups as we can observe in our hydrocarbon structure there are three hydroxyl functional groups so the main chain must encompass all three of them, therefore there is no other option but this we are proceeding to point out this is my hydrocarbon chain again we can analyze or we can in this case visualize that there are the two ends being pointed out the upper right end this lower right end the numbering starts from the end closest to the functional group if we observe in the case of the upper part the end in this case the hydroxyl functional group is 2 carbons 1 and 2 carbons from what is the end in the lower part it is also 2 carbons 1 and 2 carbons from what is the lower end that is to say it is at the same distance as we mentioned at some point when there is this tie so to speak a tiebreaker proceeds the tiebreaker is to look for the existence of a third hydroxyl group to the end that is closest this third hydroxyl group will be The end from which the numbering begins is obviously this third hydroxyl group. If this hydroxyl group doesn't exist, then we proceed to find the closest carbon chain to one of the ends, and from that end we begin the numbering. Evidently, the third hydroxyl group is much closer to the upper right end than to the lower end; in fact, it's three carbons away, while in the other configuration it's 11 carbons away, which is a lot. Therefore, having clarified this, we proceed to name it. Well, we proceed to number the carbons. We proceed to number the carbons, so it's carbon 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and 13. Normally, a hydrocarbon structure with 13 carbons is called Tribeca. In this case, having three hydroxyl functional groups, it would be Tribeca, not Friol. And we observe that the name of the compound is preserved as is, and when having two or more hydroxyl groups, the ending -ol is accompanied by a multiplicative prefix, which in this case would be -3. The prefix "tree" refers to three hydroxyl groups. Next, we need to identify the presence of branches. As we can see, there are two branches located on carbon 7. The first branch has only one carbon, so it's a metal. The second branch has two carbons, so it 's a compound. Now that all the branches are identified, we proceed to name them. As we know, we first have to name these branches. These branches are named in alphabetical order, as we already know. So the letters to distinguish are e and m, and obviously, e comes first in the alphabet. So we start with e, then we name the next one, which is methyl, ending in 77. For the "tree" branches, we proceed to name the main chain or trunk, indicating the carbons where the hydroxyl functional group is located. Remember that this numbering is from smallest to largest, that is, it has an ascending order: 23 12. And the name is already on the side, which is trio, 23 12, not trios. Again, the trio indicates the presence of three groups. Hydroxyl functional groups located on carbons 23 and 12, and this is our second structure. Okay, and now we have our third structure. As we can see, it's a more elaborate, more complex, and much larger structure than the previous two. Again, if we look closely, we can identify the presence of two hydroxyl functional groups. Once again, as step number one, we proceed to identify the longest chain. We remember that this chain must have the presence of, or must integrate, the two hydroxyl functional groups. Again, there is no other chain than the following. Okay, once we have identified the longest chain that has the two hydroxyl functional groups, we will mark it again so that there is no doubt that this chain involves the two hydroxyl functional groups. Okay, once we have it delimited in our figure, we proceed to number it. As we can see, in this case, there are two ends: the upper left end and the right end. As we remember, the numbering in this case begins at the end closest to the hydroxyl functional group. If we can see if the numbering in this In this case, starting from the far left, we would find the functional group up to carbon number 3. However, if the numbering starts from the far right, we would immediately find the functional group on what would be carbon 1. So, the numbering correctly starts from the far right. We erase the numbers and begin the numbering: carbon 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14. And since we have identified the main chain, we will now proceed to identify the branches: one branch on carbon 12, a pair of branches on carbon 10, another pair of branches on carbon 7, the same for carbon 5 and carbon 4, and finally, there are also branches on carbon 2. Once we have identified all the branches that are connected to the main chain, we proceed to identify these branches. In this case, we will start in ascending order: carbon 2. On carbon 2, there is a methyl group, which is a branch of one carbon and a symporter. Carbon branching there, regarding carbons 4 and 5, there is also a methyl pair and another methyl pair. Remember, its name is methyl or methyl, its structure is SH3D. There on carbon number 7 at the top, we have a self-supporting structure. Remember that these structures can, in this case, undergo various configurations on paper. Normally, we had previously found a smooth profile of this shape, and here it undergoes a slight variation. Similarly, we identify that it is a self-supporting structure because the free bond or connecting bond is on the intermediate carbon, which would be carbon number 2. So, since it does not undergo this variation in the structure, we can clearly identify it as a self-supporting structure, regardless of the change in its configuration and the slightly different way we are seeing it. There, at the bottom of carbon 7, there is again a style. Continuing, carbon day, the top part is a useful text; it has 4 carbons. There at the bottom is a neo pencil; it has 5 carbons in a structure surrounding a main carbon, which is the carbon in the middle, and finally, on carbon number 12, there is the The existence of another metal, well then what we are going to do now is proceed to identify which of these branches and gave first in alphabetical order the letters in this case contrast is of methyl, sorry of till m of methyl and of that gives nn open till and remember that in the case of the tertiary til there is an exception, it does not start with the tf of the prefix ternary but it starts with the b useful. Remember that in this case branches that have that exception are the tertiary til and the sec-til. The letter of the prefix ternary of the sec-til is not counted and it goes directly to the av of useful. Well then, evidently that makes the first branch that I am obliged to name the tertiary til, so it will be 10 hyphens but useful. Remember that to name these structures we are following the rules of the IUPAC which tell us that one way to name the structures based on their branches is by following an alphabetical order. Once we have named the tertiary til, we continue, what letters do we have? m of methyl ethyl and of nn To avoid lying, obviously the next letter is steel. Let's see where we have steel. In this case, we have it at carbon 2, we have it at carbon 7, and nothing else. So it's 27. We use the multiplicative prefix that indicates 2, in this case it 's d, and we write the name of the branch, leaving us with 27 and the hyphen. Now we're working with the symbols or styles. From there, the next thing we have to compare is methyl, m for methyl and isopropion. And cne open til quickly. Obviously, the next one is and we're going to check it: a b c d e f g h. And indeed, so it's 7 isopropyl again. And if at any point you have any doubts, but we quickly go through the alphabet, or it's also suggested that you have an alphabet on hand. As we practice, we'll become more familiar with it and we'll remember the order of the letters. I know it's something basic, something that has been seen before; however, it's better to be sure and double-check so as not to make a mistake. For example, now the letter that would follow would be m for methyl. Remember that in the alphabet it's mn So, n comes before n. We observe and manage in this case to identify the presence of 6 atoms: 1 on carbon 22, 2 on 4, 2 on 5, and one on 12, and nothing more. So we give it a name. It would be the first one, obviously. We indicate that there are 2, 4, and 4 carbons. Here the number is repeated because there are two constituents on carbon 4. 55 is repeated again because there are 22 substituents attached to carbon 5 and 12. We remember that between numbers the separation must be given by, in this case, through the use of commas and hyphens. And let's see, remember that we had said that there were six. The multiplicative prefix of six is ex-. So it will be hexamethyl. Since I don't have enough space, I continue it below: methyl. And we have just named the six attached. The last substituent to name, in this case, is mine. The profile will be 10. And we have already named all the substituents, so the last thing we have left is to name the trunk or main chain. For this, first we are going to indicate the number of carbons on which the... The hydroxyl functional group, which is 1, 2, and 1,2, and a hyphen, is in this case a hydrocarbon structure with 14 carbons. This is tetradecane with the presence of two hydroxyl groups, so it will be tetradecane. Enter decane, and that's it, we already have the name of our structure, which is: 27 10.000 7 mil 244 5 512 hexamethyl 10 91 12 tetradecane. And today we proceed to analyze our last structure. Okay, and we have to analyze now, as we said, our last hydrocarbon structure. As we can see, unlike the previous structures that were represented by carbon and hydrogen, this last structure is represented by the linear form where each, in this case, little peak, so to speak, represents a carbon. So the first thing we are going to do is identify the trunk or main chain, which in this case must contain the pair of hydroxyl functional groups that we have already identified in our structure. We proceed to close our trunk or main chain. Okay, let's do it very carefully, following the form. The chain is there, and it's enclosed in blue. It's my main chain. Now, very important, very important: as we can see, both chains begin, or both chains have the functional group, the hydroxyl, attached to carbon number 1. This would be the carbon from which they will start, or could start. This one here, so this could be carbon number 1, and this could be carbon number 2. Okay, remember that the rule says we must start from the carbon that is... in this case, I repeat, the rule tells us that we must start from the end that is closest to the functional group, the hydroxyl. And unfortunately, we can see that both hydroxyl functional groups are the same distance from the ends. As I said, there is a tie. This tie situation must obviously be resolved, for which we will use a tiebreaker. The tiebreaker we mentioned is locating the presence of a third hydroxyl group, and unfortunately, we cannot resort to this because there is no other functional group besides the hydroxyl. So, we go to the alternative method. In this case, we use the alternative method in the absence of a hydroxyl that would allow us to break the tie. And this method... It tells me that I should look for the nearest branch. For example, if I start from left to right, the nearest branch I find almost immediately is at carbon number 2. At carbon number 2, I find, in this case, a branch, which is this methyl group that is right here. If I continue numbering from the far right, the first branch I encounter is at carbon number 5, which is here. So, obviously, the numbering in this case has to go from left to right. And we're going to do it, and we'll erase our main cinnamon stick. In a moment, we'll restore it, and we'll indicate carbon 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14. If you observe, normally, the structures in this case, which are done on the computer, don't show these little dots because it's understood that each dot is a carbon: 15 and finally 16. Now, as I was saying, very important: do not under any circumstances count the hydroxyl groups and think that the chain in this case has 18. Remember that The chain is a carbon chain, so we only count carbons. I reiterate this because, as I mentioned before, it's a common mistake for beginners in organic chemistry, especially when starting to study alcohols. We often try to count hydroxyl groups as carbons, or we get confused and count them incorrectly. Once I've named, or rather, numbered, the main chain, we proceed to identify the branches. At carbon 2, I have a methyl group. At carbon 3, I also have a pair of methyl groups. At carbon 4, the same story applies. The same for carbon 5; I also have a pair of methyl groups. At carbon 6, I also have a pair of methyl groups. At carbon 7, I have a pair of methyl groups. At carbon 8, I have a pair of methyl groups. At carbon 11, here's very important: let's see how many carbons carbon 11 has. How many carbons does this branch have? This carbon unit doesn't have carbons 1, 2, 3, 4, 5, 6, or 7. It would be a reptile. Carbon 12 also has... Let's see how many branches there are, but it has 1, 2, 3, 4, 5, or 6 carbons. That would be a success, since we've identified the branches, which are several. Let's start naming our structure, starting, as you know, with the branches. We see that in the case of EPD, it starts with the letter h. In the case of Exile, it starts with the letter che, and its own beginning with the letter y. Still, it starts with the letter e, and I included the beginning with the letter m. Obviously, in alphabetical order, the first thing we would name would be the pair of styles. They are on carbons 9 and 10, so it would be 9 and 10. There are two of them. Their fixed flavor is di, and the branch 9 and 10 is named. And that's it. From there, we continue ab, c, d, e, f, g, h. And here we're going to have a dilemma because both it and Phil start with h, so we're going to carefully analyze both names to see which one comes first. As we can see, the first letter doesn't provide us with clear evidence of team first in this case because both start with the letter h. So, since there isn't one starting with The letter h is said to be a tie and again a tiebreaker is sought; that tiebreaker will not be provided by the second letter; the second letter of exile s, the second letter of epd and le c again in the second letter there is a tie, which is what happens if the second letter or third letter or fourth l If there's a tie, you continue until you finish the name and look for a tiebreaker. The tiebreaker isn't provided by the third letter. In this particular case, it's exile, the third letter is 3x ept, and the third letter is p, so we obviously know it comes before x. So the next name will be that of the reptile, so it's 11 reptile hyphen 12 exile, and in lowercase, steel & seal. I've already named both again. Obviously, we now have the pair of "propi" which I'm going to put at the bottom. It would be 88 and isopropyl. Here another situation arises. Many times people ask, "Hey, in this case, what is 'propi'? Am I forced to repeat it there?" Or can I simply say, "Okay, 'propi'?" And you have to repeat it? And why? The first one refers to the profile, like the body, and the second one refers to the three-carbon branch whose bond is in the middle part, which is the isopropyl. That is, if it has to be repeated, we already have what is the propi, we cross it out, and the last branch that I have left to name is the one referring to the mets, and the mets, and I have them. Let's see 12, 7, 26, 25, 24, 23, 24, 6, 8, 10, and there are 10 and 1 on carbon 2, so there are 11. He named them. Well, in this case, he didn't name the numbers or indicate the numbers where the styles are located: 1 on carbon 2, then 2 on carbon 3, 2 on carbon 4, 2 on carbon 5, 2 on carbon 6, and finally 2 on carbon 7. And again, we explain that it is evidently 11. In these topics, or rather, our exercises, we have to constantly check that the name is correct because any minimal error in the name invalidates the exercise. As I was saying before, organic chemistry is very precise, and changing, in this case, the location of a name or the location of a radical, as I was saying, can lead to the situation where the location of a radical gives you two different species, and these species are completely opposite, as I gave you the example in class. In this case, the zoom, which I was saying, shows that the difference between two compounds is... It could be determined by the location of a branch, generating in this case a first compound that would be a medicine and a second compound that would be a poison. Both are completely different, and the only thing that could differentiate them is the location of that same branch. That's why we have to be very careful and always be analyzing and verifying that our process is correct. So, let's check that they are indeed called 2, 4, 6, 8, 10, 11. I put the multiplicative prefix 11, 1 here where it's located, and finally, we're going to name the trunk or main chain. We indicate the carbons where the hydroxyl functional group is located, which is carbon 1 and carbon 16. The name of the 16-carbon hydrocarbon structure is that of khan, it 's decane, and since it has two hydroxyl functional groups, it's ex-decane. And with that, we have finished our last structure. Well, thank you for having been attentive to today's class where we studied the topic of alcohols, and we are looking forward to our next session in this We're going to begin our study of aldehydes, and so thank you very much for attending the class. We'll see you in the next study session. Take care, goodbye.
Comenzamos el estudio de los grupos funcionales. El primer grupo funcional a estudiar a detalle es el de los alcoholes.