CHEM 2211 1st Edition Lecture 6 Outline of Last Lecture I types of carbons II an hydrogens III common nomenclature naming Outline of Current Lecture I systematic nomenclature IUPAC system Current Lecture Systematic nomenclature IUPAC How to name a compound with IUPAC system 1 circle the longest continuous chain of carbon a in this case it is 6 carbons 2 if there are 2 equal chains use the most branched chain a in the example above you can see the circle include a 6 carbon chain b but the circle could go that way or this way c this is because both chains end up with 2 branches 3 number the chain with the lowest number on any branching group a in our example above we can number from left or right b from left our lowest number on a group would be 4 then 5 c from right our lowest number on a group would be 2 then 3 d this tells us to number from the right Naming the part Parent chain longest continuous C chain use the table from the last lecture for carbon chain names 6 carbons ex above would mean our parent chain name is hexane The parent chain name will go at the end of the name These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Branched groups Groups intersecting or branching off the parent chain get named as such ex above there are two groups Group off of the 2nd carbon is methyl Group off of the 3rd carbon is also a methyl The groups have to be labeled by which carbon they branch off of as just shown When multiple branching groups are the same We see this above with the 2 methyl groups A group number prefix has to be applied to them o 2 di o 3 tri o 4 tetra o 5 penta o 6 hexa o 7 hepta o 8 octa o 9 nona o 10 deca Putting the parts of the name together List branching groups alphabetically Add prefixes if multiple of same branching group Tag each group with the of carbon its attached to Separate numbers from letters with dashes Separate numbers from numbers with commas Add the name of the parent alkane at the end with no space So the name of our example chain will look like this 2 3 dimethylhexane If we end up with a chain that has a complex branched group The rules for naming it are Circle the parent chain give number 1 to the carbon attached to main parent chain Name groups of groups Groups go alphabetically Put in parentheses in the final name for doing IUPAC 1st letter counts methyl even if it s a prefix for a complex group o this is for alphabetical order in full name Example 1 1 Parent chain is circled 2 Attach 1 to the first carbon attached to the parent chain 3 Name groups of groups a Group to right of 1 carbon including 1 C propyl b Group to left of 1 C not including 1C methyl 4 1 methylpropyl 5 Final name a 4 1 methylpropyl octane
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