Question

Question 24 Assign a systematic (IUPAC) name to each of the following compounds: Br Br

Answer 1

21H Longest carbon chain has "6"carbons rootword as "hex" .In this compound single bonds present, suffix is " ane" .Methyl group is substitutent at 2 nd carbon atom and bromine group is substitutent at 5 th carbon atom and Br Br aldehyde (-al ) group is a functional group at first carbon atom. 5,5-dibromo-2,2-dimethylhexanal Longest carbon chain has "6"carbons rootword as "hex" 2) In this compound single bonds present, suffix is "ane" .Methyl group is substitutent at 3 rd , 4th and 5 th carbon atom and bromine group is substitutent at 5 th carbon atom - 2 and Ketone (-one) group is a functional group at second carbon atom . Orientation of high priority groups are clockwise direction, but above the plane is lowest priority at (3R,4S)-3,4,5-trimethylhexan-2-one4 th carbon atom (s) and Orientation of high priority groups 3) are anti-clockwise direction, but above the plane is lowest priority at 3 rd carbon atom (R) 654 Longest carbon chain has "5"carbons rootword as "cyclopent ". In this compound single bonds present , suffix is " ane" .Methyl group is substitutent at 2 nd and 5 th carbon atom and ketone (-one ) group is a functional group at first carbon atom. 2,2,5,5-tetramethylcyclopentan-1- one OH 4) Longest carbon chain has "5"carbons rootword as " pent" .In this compound single bonds present , suffix is " ane" .Propyl group is substitutent at 2 nd carbon atom and aldehyde (-al ) group is a functional group at first carbon atom. 2-propylpentanal 5) Longest carbon chain has "4" carbons rootword as "cyclobut " .In this compound single bonds present , suffix is " ane" Carbaldehyde (-al) group is a functional group at first carbon atom. 4 cyclobutanecarbaldehyde

The IUPAC name of the any compound contains 3 parts prefix+ rootword + suffix Prefix = any substitutents rootword = longest chain containing most number of carbons if the chain contains 1 carbon = meth 2 carbon = eth 3 carbon = prop 7 carbon = hept 4 carbon = but 8 carbon = oct 5 carbon = pent 9 carbon = non 6 carbon = hex and so on Suffix = if the compound contains single bond (C-C) only then suffix 'ane' double bonds (C=C) 'ene triple bonds yne For selecting prefix numbering, the substituents numbers has to be given in such way that the sum of the all substituents should be as less as possible. For selecting rootword chain, the chain with more number of carbons has to be selected In all the given compounds alkanes are present, hence the suffix is 'ane' in all the four compound For all the compounds, blue coloured part of the name is prefix red coloured part of the name is rootword and pink coloured part of the name is suffix

To know the absolute configuration at chiral carbons (carbons attached with four different groups), the priority of the attached groups has to given by Chan-Ingold-Prelog (CIP) rules. According to CIP rules the group with highest molecular weight should get first priority (1) followed by the groups with next highest molecular weights. If the attached groups are same in the adjacent atoms, one has to move further to see different atoms After giving priorties according to CIP rules, if the rotation of the priority groups (from 1st priority group to 3rd priority group) is clock wise then the configuration of that chiral center is R if the rotation of the priority groups (from 1st priority group to 3rd priority group) is anti clock wise then the configuration of that chiral center is S If the least priority group (40 is present above the plane then the configuration of the chiral center should be opposite. That means R becomes Sand S becomes R