 Okay, let's write down this and trans nomenclature we use when identical group present in the present on the double bonded carbonyl. Double bonded carbonyl. ENC nomenclatures we use in case of more substituted alkane. Sir, could we use ENC in case of this example that you gave us? Here we are going to use. In case of nitrogen containing compound, like suppose we have C double bond N and double bond N. Sir, is E used when both of them are on the same side or different side? We will discuss now. We have to assign the priority first of the group attached on to the double bonded carbonyl. See for cis and trans isomers it's very simple. The double bonded carbonyl atom if they contains identical group on the same side P and Q. Then it is cis, C double bond C, P, Q, P and R with respect to P we can say this is cis. To find out this ENC isomers we have to assign priority on the group attached on to the double bonded carbonyl. So first of all we will assign the priority on the group attached to the double bonded carbonyl. If higher priority group on the same side that is z isomer, z isomer. If higher priority group or on the opposite side it is E isomer. Higher priority same side Z, higher priority opposite side E isomer. So why do we say z isomer? Why do we say z isomer? It's a Greek word, I don't remember that word exactly but according to that we will take this. Now the thing is how do we assign priority on to this? To assign priority we have a rule and we call it as sequence rule or CIP rule. To assign priority we have a rule we call it as sequence or CIP rule. CIP rule C, I, N, P based on the name of the scientist. C stands for Carl, I is in gold and P is prelogged. Name of the scientist. C H N I guess. Carl in gold and prelogged, CIP rule. So what is this rule? First point to write down. Higher atomic number will have the higher priority. So if the atoms are attached directly on the double bonded carbon atom then we will see the atomic number of that. Higher atomic number, higher will be the priority. Second point, in case of isotopes, in case of isotopes we will compare the mass number. Like if we have oxygen 18 and oxygen 16, the priority of oxygen 18 is more over oxygen 16. Plurin 37, Plurin 35, priority order is this. Tritium, priority order is this. We compare the mass number when isotopes are present. Third point, if groups are attached to the double bonded carbon atom then we will compare the atomic number of first atom. For example, if Plurin is there, SO3H is attached to the double bonded carbon atom. Hydroxy group OH is attached, NH2 is attached or suppose we have COOH attached to the double bonded carbon atom. So we will compare the atomic number of the first atom, the atom which is attached to the double bonded carbon atom. Here it is oxygen, nitrogen and carbon. Plurin, what is the atomic number? 17. Atomic number of sulphur is 16, 8, 7 and 6. So more atomic number more will be the priority. Priority order is this. Right on lone pair is considered to have the least priority. Lone pair we also consider as a group attached onto the double bonded atom and that will have the least priority. Secondable bond COOH and CH3 and Plurin. Assign the priority E,N,Z, cis, trans, what do you do? Once we assign priority to these things, what do we do with them? So first you tell me the priority here. See we already assigned priority on the atoms or groups which attach to the carbon atom, double bonded carbon atom. So these two will assign priority 1 and 2 or 2 and 1, these two 1 and 2 or 2 and 1. So what is the priority of OH and H? Oxygen and Hydrogen. This is first and this is second. What about this one? First and second. So higher priority group on the opposite side, here it is 1, here it is 2. Higher priority opposite side it is E-Ice. So at what point does cis and trans not matter anyway? How many C's do they have? Do not see, if you have all the 4 atoms different then we do not assign cis or trans. Here you see we have 3 different atoms, bromine, chlorine and hydrogen. So with respect to bromine we can say this is cis. But for the first phase what cis it is more subsidiary alkene. So we write it as E or Z-Ice. If you have B-C's or 4-C's or something, does cis and trans still make a difference? How is 3-C and 4-C? Like this you are saying? Yes. So let's see that across the double bonded. Across the double bonded. So we always look at priority across one of the double bonded carbon atoms. 3-DM, isotope of hydrogen. 3-DM, 2-DM and then 4-DM. What is the priority here? Which one is 1? 3-DM has 1. You see higher priority than hydrogen? This is 1 and this 2? Nitrogen and carbon? Nitrogen. Same side? Same. What about this one? Synth or N-D? Synth or N-D. Sir, how do you know this one? Here it is non-pair. So non-pair is 1. What is another? Non-pair is reached at the same at which side? What? Which one is like the system? Which is synth? Opposite, higher priority opposite and N-D. Same side, synth. Higher priority same side, synth. Higher priority opposite and N-D. Synth and N-D we use in carbon nitrogen double bond. Synth like synth. Synth, S-Y-N. S-Y-N, S-Y-N, S-Y-N, S-Y-N, S-Y-N, S-Y-N, S-Y-N. So E and Synth are same? No. Nitrogen? No. So if it has nitrogen. Only nitrogen is same? Yeah. If it has nitrogen, then carbon. Then E and Synth are same. So in rest of the higher priority we have left for O-H? Yes. Okay. This one? One and? One. One. So we can write this as sys or preferably we will write it as? So what if instead of that chlorine there was an iodine? Then how would we do it? So would we go bromine and iodine? I'll write a little. Six. Six. So like iodine is a little? One. And one? Okay. So with respect to this, this is sys. And how would we write it? If we write the name, what would we write? Preferably we'll write E or C. But if somewhere it is sys also written it is not wrong. But you can write down the name of this. We'll have the E isomer of it. So with respect to bromine and sys, but with respect to that thing it starts? That's what. Well, we have substituted alkene. Then we'll write ENZ. Sir, but would we write E or C for this? Because this is an E. Bromine and iodine. Higher priority is this too. Opposite side is E. Sys can be E. Sys can be zero. Sys is only for the same type. Yes, that's what. Identical group on the same side of double bonded carbon. Atomite is sys. E or sys you can write for this. Z or sys you can write for this. I didn't say E is sys. I said sys can be E or z. It is not necessary that sys is always z or always E. Example I'll give you here. With respect to bromine it is sys, which you understood. If you write sys it means we're talking about this is with respect to bromine only. Sys, and when you assign the priority, higher priority on the opposite side. So it is E. Here you see with respect to bromine again it is sys. Higher priority is the same side. Sys can be E or z. Trans can also be E and z. So if it is written sys is z and trans is E. That is not true. Understood? So write on these two examples. But opposite side we have higher priority opposite side. E is always opposite. It's only defined for carbon element. Write it down. So if you have an N there and E is the same as trans so is there another thing where you can have sys and an E and trans. So if you have an N there like it's C N then can it be sys and trans and it is an E only. We'll write N T only for that. Sir E right? For carbon this one. I don't know. I'll just draw it randomly. You'll see. Which one is the higher priority? Water one. Water one. Why? It's the same. It's only the first carbon atom. Okay, see here. See if you have like this subcycling structure attached then how do we compare? This carbon atom let it be here. This carbon atom is this. What is the first atom? Carbon. What is the first atom here? Carbon. Right? Here also we have carbon. We'll open up this thing. Either you can go clockwise or anticlockwise one by one next action. I said this carbon is here. This attached is one carbon and this another carbon. These two are the carbon atoms. Then we go this way. Clockwise. Clockwise. You can go anticlockwise. So both have to be clockwise or anticlockwise. Clockwise, clockwise, anticlockwise. So carbon then what we get? Oxygen. Carbon. Then carbon. Carbon, oxygen and then carbon. Till here. We have the first one again. Yes. Here what happens? Carbon, oxygen. Carbon, carbon, carbon, oxygen and carbon. Okay. Now we'll compare one by one. Right? So this we have carbon only. So we cannot compare carbon, carbon. We cannot decide. Oxygen, oxygen we cannot decide. Carbon, carbon we cannot decide. Carbon, carbon we cannot decide. Here we can decide. Oxygen has more priority over carbon. It means this group has higher priority over this group. Sir what if going clockwise and anticlockwise gives us different results? They won't give you that. So this is smaller ring. First priority. This is second priority. Here also you can compare the smaller ring and higher priority. This one is. And this one. Similar ring if it is present. Smaller ring will have the higher priority. Okay. So all these I don't know. In patient we have discussed his trans, EZ, syn, and D.