hi today we will discuss six-membered and higher heterocyclic rings in easy way in our previous video we have discussed the three member to the five membered heterocyclic ring systems and what is their norm enclosure and today we will discuss the six membered and higher ring systems and what is the nomenclature and how we can give the numbering to these heterocyclic ring systems now let us go over the six membered ring systems so the simple ring system is the the six membered ring system with one hetero atom as the nitrogen so all we have seen this is the P reading so pyridine is the the nitrogen containing six membered ring system and if it is oxygen is present then it is called as PI R on but in this PI R on second position is saturated because oxygen is hanging the valency has only two so the second position should be saturated so here we are going to indicate the point of saturation with its position and letter H so two H indicates second position is saturated so this is a 2 H PI R on again here we are not following any particular suffix so they should be well known with their common names like the pyridine and pi wrong now the 6 membered ring systems with two hetero atoms now here we can add an end there a hetero atom nitrogen at the second position otherwise we can add the end reheater atom at the third position and finally we can also add this hetero atom at the fourth positions so nitrogen's can be present at the first and second position or first and third position or first and fourth positions now how can we write the name for these ring systems here the first one is coming from the pyridine and an extra nitrogen is there like the esse just like in the pie resolved which is a 5 membered ring system here we can you apply the same logic so pyridine within the period n we are going to introduce that as a so period plus SR plus ein so that is a period of time if you remove the edge it's simply pyridine so within the pyridine we have introduced the aza because it is hang an extra nitrogen at the ads end position so that is a period and what about the second one so just like the previous imidazole so here fireplace even amid indicates that is a meta position that is the third portion and is a six membered ring system that is the iron has a suffix so PI R plus e mid plus sign so this is the pyrimidine so pyrimidine is anga nitrogen's at the first and third positions and what is the name for the last one here the one of the nitrogen can be indicated as a PI and n the nitrogen as the aza and suffix as ein so fire plus has a plus sign that is the PI resign so here we had to remember that in the pyridine nitrogen is present into the second position so we have written the period but in the PI resign it is present at the fourth question we have taken only prefix PI so P redesign is 1 2 and PI resign is 1 4 so here we have three types of heterocyclic ring systems with two hetero atoms so P redesign pyrimidine and PI resign now let us go to the 6 plus 5 membered ring systems so this is one of the 6 plus 5 membered ring system the 6 membered ring system is the simple benzene and second one is a heterocyclic ring system which can be called as PI role so simply it can be written as benzo pyrole but actually this ring system is commonly known as indole so in delicious six plus five membered ring system with the nitrogen as the hetero atom similarly another one is the benzene with Iran when the benzene is going to be fused it can be written as benzo plus fewer on so it is a benzo few wrong similarly this structure benzo plus thiophene this is the benzo thiophene these names can be directly derived by using the whatever this term benzo when the benzene is going to be fused with the heterocyclic ring systems now let us take another example with the six plus five membered ring system with two hetero atoms here so what is the name of this one so now here the water the heterocyclic ring system is the imidazole which is attached with the benzene so bench plus image all there is a Benjamin soul so here we have not used the whoa because it is not easy to pronounce so benzo virtual is simplified as Benjamin and so similarly another one is the benzene with the oxygens now here this is the binge +13 oxygen so that is a 1/3 binge oxygen similarly third structure with the sulfur so again here binge +1 three tides all there is a 1/3 been jota's all now let us go to the 6 plus 6 member ring systems so this is one of the 6 plus 6 membered ring system with having nitrogen so again this heterocyclic ring system is commonly known as Queen Arlene so here the nitrogen is present at the first position if suppose if position of the nitrogen is going to be changed like this now here the nitrogen is present at the second question so this is called as ISO Queen only so crinoline and ISO Queen early Queen only needs one of the important ring system in the present in the animal areas like the chloroquine may flow Queen and isoquinoline is one of the important ring system present in the smooth muscle relaxant like the papal ring now six plus six membered ring system with two hetero atoms so this is the one of the ring system so this is wondering where the nitrogen's are present at the first and second position this ring is commonly known as seen Nolan and the nitrogen's can also be present at the first and third position then this name of this ring can be derived from the the base name Queen Holly so because if single nitrogen is present that is Queen olan so Quinn Olin plus extra nitrogen as Asia that is Queen azulene similarly if the nitrogen is present at the first and fourth position then it is commonly known as queen ox alleyne here don't think that boy X indicates ogz in his present this ring is commonly known as Queen ox Elaine where the nitrogen's are present at the first and fourth positions these rings are well known with their common names we have to remember as it is the next one is the Ender heterocyclic ring system but here you can observe that the nitrogen's are not present at the first position so if we give the name ring here this is 1 2 3 & 4 that means here the nitrogen's are present at second and third positions how we can give the name for this compound so if we compare this ring with the aromatic rings is having Turing's so this is nothing but simply naphthalene so from the naphthalene we can derive a small part which can be used for the naming of this heterocyclic ring system so from naphthalene we can take the tile as one of the pot so from the naphthalene we can take the fal and since the nitrogen is present we can use the azza but here we are not using the die as a-- even two nitrogen's are present simple we are indicating the nitrogen's which are going to replace the carbon as the adds up and the nitrogen's are present in the six membered ring system so on so what are the complete name is the Teledyne so here we are going to discuss like this in order to remember very easily because in the six plus six membered ring system the two nitrogen's can be present at the first and second position first and third portion and first and fourth question as well as they can also present at the second and third position so when they are present at the second and third position we can simply compare it with the naphthalene and from that we can derive the name so the water this heterocyclic ring system is derived from the naphthalene ring and the name is the Teledyne this thelusson ring is present in one of the drug hydralazine hydrogen is a vasodilator used to treat the hypertension as well as in the treatment of L apprecia next let us go with the other rings so now this is a ring of six plus seven membered ring system and here you can observe it is angry again two hetero atom that is the nitrogen's so from which position we have to give them M bring always in the compote hanging two or more rings we have to give the name break from the atom adds into the bridgeheads so we can give the numbering either from this atom are from this atom which are adds into the bridgeheads bridgeheads are nothing but what are the atoms which are which are involved in the fusion between the two rings so we can start the numbering from any of these atoms but if we start an ambering from this nitrogen 1 2 3 4 5 we can give the lowest number to the both of the nitrogen so this numbering is correct so nitrones are present at 1st and 4th positions and here you can observe that the third position is saturated it is not attached with any double bond so which we can indicate with any indicated hydrogen 3 hitch so if we give the name this is three hitch plus benzo because benzene is going to be fused benzo and nitrogen's are present at the first and fourth position so one for dyadya and this is a seven membered ring system with nitrogen so whatever the suffix is the e pi n-- so by combining all these we can get the name as three hitch bender daiji pine are three hitch one for benzodiazepine simply we can write benzodiazepine because most of the benzodiazepines are hanga nitrogen's at first and fourth position so this is the three hits one for benzodiazepine similarly we can go with the end the ring where here it is saying the sulfur and nitrogen so we can start the numbering from the sulfur because sulfur should be given more preference than the nitrogen so this is one two three four and five so just like the previous one but here there is no saturation point so simply we can write benzo plus one-fourth ir h r+ e pine so that is the one for benzo Taiji pine or simply we can write benzodiazepine but it should be indicated as one for benzodiazepine because we also have one 5 benzodiazepine so in order differentiate we have to indicate it with the one four so the water the ring system is the benzo Taiji pine similarly another one here you can see that three rings are there so it is a tri cyclic ring system so from which atom we had to give the numbering here sulfur should be given the least number but we cannot start the numbering from the sulfur because sulfur is there in the middle ring we cannot start the numbering from middle of the ring we should start the numbering from any of the terminal so let us start here this is one two three four and five so in this way we have given the least number to the sulfur that is five if we try to give the numbering in reverse direction sulfur will get the more number which is not correct so sulfur is given the fifth number then 6 7 8 9 and 10 so now the sulfur is present at the fifth portion and nitrogen is present at the tenth position and because the nitrogen is saturated here we can indicate this as 10 H so 10 H fino even here two phenyl groups are there but here we are not using again - I'll or DYFS you know simple we are going to indicate by few know that means phyno indicates the phenyl group is going to be flanger on both of the sides of this heterocyclic ring system so 10h plus vino plus sulfur is indicated by thea and nitrogen is indicated by a za and sulfur and nitrogen are present within a six membered ring system so the suffix is i combining all this we will get 10 h phenotype so phenotype gendering system is present in the well-known drugs which are used as the antipsychotics like chlorpromazine try flu from giant flu finish line in all of these phenothiazine ring system is pressing similarly another heterocyclic ring with so many hetero atoms here you can observe for hetero atoms are there and the numbering is somewhat different in this ring system this ring system is made up of two heterocyclic rings one of the heterocyclic ring is made up of pyrimidine and then there's heterocyclic ring is the imidazole so this is a imidazole of pyrimidine but if we give the numbering here so we have to start the numbering from the pyrimidine ring so 1 2 3 4 and here you can see that we are giving numbering even to the bridgeheads in the previous examples we are not giving the numbering to the what of the Brigid hats but in this structure we will give the numbering to the bridge it heads so for then we are giving the 5 and 6 that means we are completing the numbering to the pyrimidine ring initially then to the image all we are going to continue there so 7 8 & 9 so saturated nitrogen is indicated by 9th position so this is commonly known as a purine ring which can be indicated as 9h purine so 9h purine is a Amira jolo pyrimidine but it is commonly known as pure in ring system in this way we can have lot of heterocyclic ring systems and in many of these heterocyclic ring systems we can remember the name by using some logic by using some prefix and suffix and otherwise we can compare the rings with the other rings so that we can remember their names very easily so that's about the heterocyclic ring systems naming and numbering if you liked this video please don't forget to subscribe to our channel and click the bell notifications and please share 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