hello everybody my name is Iman welcome back to my YouTube channel today we're going to be talking about alcohols and in this chapter what we plan on covering is first a discussion on the description and properties of alcohols this is going to include talking about nomenclature as well as physical properties then we're going to move into talking about reactions of alcohols this is going to include a discussion on oxidation reactions mulates and toilat as well as protecting groups and then we'll end the chapter with a discussion on the reactions of fennels all right here we're going to talk about Quinones and hydroxyquinones as well as UB quinone all right so let's go ahead and get started now alcohols we've talked about them in previous chapters but they have the general formula R all right with the functional group O referred to as a hydroxy group now alcohols are named in the IUPAC system by replacing the E ending of the root alkan with the ending o all right so you replace that e with o if the alcohol is the highest priority functional group the carbon atom attached to it is going to receive the lowest possible number so here we can see some examples all right we have an alcohol group at the second position all right this is a one two three carbon chain three carbon chains are called propane all right now we have an alcohol group so we replace this E ending with o all right so instead of propane it's going to be propanol all right and then we just have to add in the number to indicate where this hydroxy where this hydroxy group is it's at position two so the name of this molecule is two propanel all right propenol I should really focus on making the o sound correct here all right here's another example we have a carbon chain 1 2 3 4 5 6 it's a six carbon chain we would typically name that hexane all right but when there's when when the highest priority functional group is our hydroxy group then we replace that e with an O so it's going to be hex anol all right and then you go about using the same naming convention and there should be a methyl right here all right so this is going to be we're going to start naming it on this side because we want this hydroxy group to have the lowest number so one 2 3 4 five 6 all right we have two methyl groups at four and five so the name of this molecule is four five dimethyl two hexanol all right the number is going to be associated with the parent name all right especially because the parent name has been changed to indicate that there is an alcohol group hence why the two is here and not the first thing that we state in the name for this molecule now alternatively the common naming practice is to name the alkal group as a derivative followed by alcohol so another way we could approach this all right is we can name the alkal group as a derivative and then follow it by alcohol so this would be all right there's a two carbon chain ethane all right what we could say that this is is one ethanol all right and alternatively you can also say ethyl alcohol so notice how we name the alkal group as a derivative and then we just follow it with alcohol we see the same here this is an isobu uh group so we call this isobu alcohol fantastic now when the alcohol is not the highest priority group it's named as a substituent with the prefix hydroxy all right so that's the takeaway if the alcohol group is not your highest priority group something else that's also important for us to talk about is we're going to also see that hydroxy groups can be attached to aromatic Rings all right these compounds are called fennels so you can see that right here you have a Benzene ring with an alcohol group attached to it you have an aromatic ring with an alcohol group attached to it this is called aenl the hydroxy hydrogens of fennels are particularly acidic by the way and that's due to the resonance within the fenel ring now sometimes all right you can have Benzene rings that contain two substituents whether it be an alcohol or two alcohols alcohol in another group all right or two other groups that are not alcohols there's an important naming convention or a a assignment all right when a Benzene ring contains two substituents all right and what that is is that their relative positions have to be indicated and the way that we do this is using the following words Ortho Meta and para all right so two groups on adjacent carbons like we see here you have an alcohol group on this carbon and a bromine group here on this adjacent carbon these two groups are right next to each other all right so when we name this molecule we started off with an O for Ortho all right Ortho bromoenol all right two groups that are separated by a carbon so as we see here we have an alcohol group and a methyl group and they are one two carbons away all right this is referred to as meta or just letter M so you can see here metac crestle all right and this is M methyl fenel in other way in other words all right so this is more so of the common name all right but notice the M we denote M here to note that the alcohol and the methyl group are meta to each other they are two carbons away from each other all right now two groups that are on opposite sides of the Ring they're called parah or also denoted with just a p so for example this molecule is Paran nitr fenol all right notice that they are on complete opposite sides of each other all right now in this first objective besides just nomenclature we really want to talk about physical properties of alcohols and one of the prominent properties of alcohols is that they are capable of intermolecular hydrogen bonding which results in significantly higher melting and boiling points than those of analogous hydrocarbons all right so molecules with more than one hydroxy group are going to show even greater degrees of hydrogen bonding and this is evident from boiling points that you can compare so you might have a couple of molecules that look like you might have this hydrocarbon all right then you have this alcohol all right let's say that this molecule has two alcohols all right what you'll notice all right is that the boiling point of this molecule is- 42° C the boil point of this molecule is 97° C and this is almost 190° C so boiling point increases with significantly with additional hydroxy groups which permits more hydrogen bonding and hydrogen bonding occurs when hydrogen atoms are attached to highly electronegative atoms like nitrogen oxygen or Florine hydrogen bonding is the result of the extreme polarity of these bonds and in the case of a hydroxy group The electronegative oxygen pulls electron density from the less electronegative hydrogen atom and what this does is it generates a slightly positive charge on the hydrogens and a slightly negative charge on the oxygen and so then the partially positive hydrogen of one molecule electrostatically attracts The partially negative oxygen of another molecule all right and that generates a non-covalent bonding Force that's known as hydrogen bonding now one additional note here is that the hydroxy hydrogen is weakly acidic and alcohols they can dissociate into protons or alkoxide ions in the same way that water dissociates into Pro uh protons and hydroxide ions all right so with that we have covered our first objective all right our second objective is reactions of alcohols and actually actually we've covered a lot of this information briefly in the previous chapter when we were giving an overview of how to analyze organic reactions of course all of those reactions that were mentioned in that chapter briefly are ones that we will further elaborate on starting here all right so in the main reactions actually that you will see on the mcap for alcohol specifically they're going to include oxidation they're going to include preparation of mesilat and toilat and also protection of carbonal by alcohol so those are the three main reactions of alcohols we want to cover here starting all right starting with oxidation all right and we've covered this briefly but oxidation of alcohols it can produce several products all right and we can start from the very beginning we can say that primary alcohols all right like this right here this is a primary primary alcohol they can be oxidized to alahh highes but only by uh pyrodinium chlorochromate also known as PCC all right this is a mild anhydrous oxidant all right and notably this reactant it stops after the primary alcohol has been converted to an alahh because PCC it lacks the water necessary to hydrate the otherwise easily hydrated aldhy all right so this is the first important reaction we should know all right we can we can have oxidation of primary alcohol hols to an alahh by PCC make sure you know this now secondary alcohols secondary alcohols they can be oxidized to ketones by PCC or any stronger oxidizing agent all right we're about to talk about that right here one note though tertiary alcohols they cannot be oxidized because they are already as oxidized as they can be without breaking a carboncarbon bond now the oxid the oxidation of primary alcohols all right with a strong oxidizing agent like chromium all right will produce a carboxilic acid now in the process chromium 4 I should say I should specify is reduced to chromium 3 now common examples of chromium containing oxidizing agents are going to include sodium and potassium di chromate salts which are the ones that you're more likely going to encounter on the MCAT all right these kinds of oxidizing agents they can take a primary alcohol all the way to a carboxilic acid all right so we're talking about sodium chromate all right or potassium chromate all right they can take a primary alcohol convert it to a carboxilic acid all right what they can also do is they can take they can convert a secondary alcohol like we see here to a ketone all right through the use of these di chromate salts all right so as with other strong oxidizing agents all right these are going to these these chromate salts are going to fully oxidize primary alcohols to carboxilic acids and they're going to oxidize secondary alcohols to ketones like we see here all right so that's the next important thing that we should know all right now an even stronger chromium containing oxidizing agent is chromium trioxide that's this is CR um CR without the two ignore that C3 all right that's chromium trioxide when dissolved with dilute sulfuric acid and acetone all right this is called a Jones oxidation and as expected this reaction oxidizes primary alcohol right here all right to carboxilic acid or it can take secondary alcohols to Ketone so what we see here in this particular example though this is a primary alcohol that's being oxidized to a carboxilic acid but I just want to note all right that Jones oxidation can take a secondary alcohol and also convert it to a ketone all right so we've been introduced to a couple of different oxidizing agents that can take primary alcohols to carboxilic acids and that can take secondary alcohols to ketones all right those are going to be our chromium salts here all right our di chromium salt and our chromium trioxide fantastic so that's for that's that's our oxidation reactions for alcohols something el else that we want to talk about is mulates and toilat so the hydroxy group of alcohols are fairly poor leaving groups for nucleophilic substitution reactions however they can be protonated or reacted to form much better leaving groups all right and the way that we do this all right is by converting these alcohols to meates and toilat all right so these alcohols they can be protonated or reacted to form much better leaving groups that are called meates and toates so a mesilate is a compound containing the functional group s O3 ch3 all right it is derived from methane sulfonic acid all right and it's shown here all right meates they can be paired using methyl sulfonyl chloride and an alcohol and an alcohol in the presence of a base all right then we also have toates toss lates contain the functional group S3 C6 H4 ch3 they're derived from toine sulfonic Acid these compounds are produced by reaction of alcohol with Paraline sulfon chloride forming Esters of toine sulfonic acid all right and this is the structure of a toss all right so if we since alcohols are not great leing groups we can convert them to these mulates or toilat and then they can act as better leing groups for nucleophilic substitution reactions now in addition to making hydroxy groups um of alcohols into better leaving groups for nucleophilic substitution reactions they can also serve as prot acting groups when we don't want the alcohols to react so if you have a synthesis that you're trying to you know write up and you have an alcohol group that you want to protect from your starting product to your end product but you're going to react this kind of molecule with things that might replace or change your alcohol group and you don't want that what you can do is convert that alcohol to a mesilate and tosilate they can serve as protecting groups you you can go about your synthesis and at the end when you've completed your synthesis and now you want that alcohol group back you can remove the protecting group all right and we're going to talk about ways that we're going to do that but conceptually I want I want to drive that point here all right now speaking about protecting groups all right alcohols can actually also be used as protecting groups for other functional groups themselves all right so for example alhida and ketones can be reacted with two equivalents of an alcohol or a dial so that they can form acetal or ketal acetal are primary carbons with two o groups and a hydrogen atom and ketos or or ketos are secondary carbons with two o groups all right we can see that here here this is an acetal this is a ketal all right fantastic now carbonal they are very reactive with strong reducing agents like lithium aluminum hydde acetals and ketals on the other hand they don't react with a lithium aluminum hydride so if you have a ketone or alahh that you want to protect as you go about your synthesis all right as you go about your synthesis you're going to want to protect this group and the way that you can do that is using alcohols as protecting groups so you can start by treating this starting material with a dial all right what this is going to do is going to it's going to replace this carbonal all right to form a ketal all right and then you can go about your synthesis until you reach the very end once you've accomplished what you want which is here the case is replacing this with a alcohol group all right um then you can go ahead and remove this protecting group all right and get back your Ketone all right and so alcohols can be used as protecting groups for other functional groups themselves and this right here depicts the protection of a ketone by ketal formation using a d alcohol now last but not least we're going to talk about our third objective which is reactions of fennels all right reactions of fennels they proceed in a very similar fashion to reaction of alcohols all right the thing to not as a reminder is that the hydrogen in the hydroxy group of fenals it's particularly acidic because the oxygen containing anion is resonance stabilized by the ring and specifically today we really want to talk about uh Quinones and hydroxyquinones all right starting off with a fennel all right that you can do treatment of fennels with oxidizing agents so that you can produce compounds called Quinones and so what we see here is the oxidation of parab benzene diol which is a hydroquinone all right to a quinone which is this product right here all right this is called 14 benzoquinone now quinon are named by indicating the position of the carbonal numerically and then just adding quinone to the name of the parent fennel all right now due to the conjugated ring system these molecules they are resonance stabiliz ized electrophiles all right they're not necessarily aromatic because they do lack the classic aromatic conjugated ring structure all right but some Quon do have an aromatic ring this is just not the case right here all right it's just not always the case now Quon they serve as electron acceptors biochemically specifically in the electron transport chain in both photosynthesis and aerobic respiration actually what you see here this is known by its common name vitamin K this is a common quinone all right it can be refer it's it's referred to as Vitamin um K1 or Pho quinone and it's important for for photosynthesis and the carboxy of some of the clotting factors in blood all right now these molecules they can be further oxidized to form a class of molecules called hydroxyquinones they share the same um ring structure they same they they share the same ring and carbonal backbone as Quinones but they just differ in by the addition of one or more hydroxy group all right so I don't have it here but we can draw an example an example of a Hydrox uh hydroxy kunon would be if this structure had an O group right here for example all right so they share the same ring and carbonal backbone as Quinones but they differ by the addition of one or more hydroxy group all right all right now because of resonance hydroxy Quinones they also behave like Quinones with electron donating groups and that makes them slightly less electrophilic uh although still reactive now the last thing I do want to talk about all right is Ubbi quinone all right the UB quinone is one example of a biologically active quinone it is also called co-enzyme q and it's a vital electron carrier associated with complexes 1 2 and three of the electron transport chain um it is the most oxidized form that this molecule takes physiologically all right it can also be reduced to UB quinol upon the acceptance of electrons and this oxidation reduction capacity allows this molecule to perform its physiological function of electron transport all right with that we've covered everything we need to to know for this alcohol chapter in the next video we're going to do some practice problems together other than that good luck happy studying and have a beautiful beautiful day future doctors