1 1.9 LINE NOTATION Organic chem models: ourses/chem130/molecules/models.ht ml ourses/chem130/molecules/models.ht ml

2 The end of any line indicates a carbon atom, unless another atom is indicated. Any place where two or more lines meet represents a carbon atom, unless another atom is indicated. Any missing valencies are filled by adding hydrogens. RULES FOR LINE NOTATION 1) 2) 3) 4)All non-carbon atoms are clearly indicated. 5)Unshared pairs are implied, but not shown.

3 LINE NOTATION

4 STRUCTURES INVOLVING HETEROATOMS A “heteroatom” is any atom different from carbon or hydrogen. “hetero” = different (Greek) There is no carbon here, another atom is indicated.

Classification of carbon atoms C C PRIMARY CARBON C C C C C C C C C C C C SECONDARY CARBON TERTIARY CARBON QUATERNARYCARBON CONNECTED TO ONE OTHER CARBON CONNECTED TO TWO OTHER CARBONS CONNECTED TO THREE OTHER CARBONS CONNECTED TO FOUR OTHER CARBONS

6 QUATERNARY PRIMARY TERTIARY SECONDARY A hydrocarbon containing carbon atoms with differing degrees of substitution All of the methyl groups (CH 3 ) are primary. EXAMPLE

7 1.11Branched chain alkyl groups MEMORIZE THESE

8 isopropyl propyl ethyl methyl NAMES OF SOME COMMON ALKYL GROUPS CH 3 CH 2 CH 3 CH 2 CH 2 CH 3 CH-CH 3 CH 3 C1 C2 C3 Attached to 2 o C of propane

9 NAMES OF SOME COMMON ALKYL GROUPS ( continued ) sec -butyl isobutyl butyl CH 2 CH 2 CH 2 CH 3 CH 2 -CH-CH 3 CH 3 CH-CH 2 -CH 3 CH 3 (t -butyl) tert-butyl C-CH 3 CH 3 C4 Attached to 1 o C of isobutane Attached to 2 o C of butane Attached to 3 o C of isobutane CH 3 -CH-CH 3 CH 3 CH 3 -CH-CH 3 CH 3 CH 3 CH 2 CH 2 CH 3

10 SOME GENERALIZATIONS chain ends in two methyl groups = iso chain tert -butyl attachment is to the 3 o carbon isopropyl, isobutyl, isopentyl ….

11 ALPHABETIZATION isopropyl, isobutyl, isopentyl …... one word, no italics ALPHABETIZE UNDER I sec - butyl, tert - butyl …. italics are ignored ALPHABETIZE UNDER B

12 Choose... 1.isopropyl 2.sec-butyl 3.isobutyl 4.tert-butyl CH 3 -CH-CH 2 -CH 2 -CH-CH 2 -CH 2 -CH-CH 2 -CH 2 -CH 3 CH 3 CH 3 -CH-CH 3 CH 2 -CH 3 SPECIAL GROUP NAMES ARE OFTEN CONVENIENT ON A LONG CHAIN CONVENIENT ON A LONG CHAIN and allowed by the IUPAC

13 ALWAYS PICK THE CHAIN WITH THE MOST SUBSTITUENTS WHEN MORE THAN ONE CHAIN OF THE SAME LENGTH IS POSSIBLE : This will avoid using the special groups in favor of simpler ones ….

14 CH 3 -CH 2 -CH-CH 2 -CH 2 -CH-CH 2 -CH 2 -CH 3 CH 3 -CH-CH 3 CH 3 CHCH 2 CH incorrect 6-sec-butyl-3-isopropylnonane What is the correct name?

15 SOME FINAL EXAMPLES

16 If you can name this, you can name anything!

17 ALPHABETIZATION RULES

18 FIVE CASES OF ALPHABETIZATION CASE 1 arranging order with no prefixes 3-ethyl-2-methylhexane CASE 2 arranging order with prefixes 5-ethyl-2,3-dimethylnonane multiplier (di) is ignored CASE 3 arranging order according to locant number 3-ethyl-4-methylhexane not 4-ethyl-3-methylhexane ethyl before methyl

19 ….. AND DON’T FORGET CASE 4 italicized prefixes do not count in alphabetizing tert -butylalphabetize under B t -butyl sec -butyl CASE 5 groups without hyphens DO alphabetize using their first letter isopropyl isobutyl alphabetize under I