1. Organic Functional group and Stereochemistry

2. Families of Organic Compounds Organic compounds can be grouped into families by their common structural features. We shall survey the nature of the compounds in a tour of the families in this course

4. Functional Groups Functional group - collection of atoms at a site within a molecule with a common bonding pattern The group reacts in a typical way, generally independent of the rest of the molecule For example, the double bonds in simple and complex alkenes react with bromine in the same way.

5. Types of Functional Groups: Multiple Carbon–Carbon Bonds Alkanes have a C-C single bond Alkenes have a C-C double bond. Alkynes have a C-C triple bond

6. Groups with a Carbon–Oxygen Double Bond (Carbonyl Groups Aldehyde: one hydrogen bonded to C=O Ketone: two C’s bonded to the C=O Carboxylic acid:  OH bonded to the C=O Ester: C-O bonded to the C=O Amide: C-N bonded to the C=O Amine: C bonded to N (C-N) Carbonyl C has partial positive charge (  +) Carbonyl O has partial negative charge (  -).

7. 7 Groups with a Carbon–Oxygen Double Bond (Carbonyl Groups)

10. Alkanes and Alkane Isomers Alkanes: Compounds with C-C single bonds and C-H bonds only (no functional groups) Connecting carbons can lead to large or small molecules The formula for an alkane with no rings in it must be C n H 2n+2 where the number of C’s is n Alkanes are saturated with hydrogen (no more can be added They are also called aliphatic compounds

11. Names of Small Hydrocarbons No. of CarbonsFormula Name(C n H 2n+2 ) 1MethaneCH 4 2EthaneC2H6C2H6 3PropaneC3H8C3H8 4ButaneC 4 H 10 5PentaneC 5 H 12 6HexaneC 6 H 14 7HeptaneC 7 H 16 8OctaneC 8 H 18 9NonaneC 9 H 20 10DecaneC 10 H 22

12. Names of Larger Hydrocarbons No. of CarbonsFormula Name(C n H 2n+2 ) 11UndecaneC 1 2 H 26 12DodecaneC12H26C12H26 13TridecaneC13H28C13H28 14TetradecaneC 1 4 H 30 15PentadecaneC 1 5 H 32 16HexadecaneC 1 6 H 34 17HeptadecaneC 1 7 H 36 18OctadecaneC 1 8 H 38 19NonadecaneC 1 9 H 40 20IsocaneC 20 H 42

13. Different Ways to Write Butane

14. Isomers Isomers: are molecules with the same molecular formula, but different arrangements of atoms. There are different types of isomers, shown by the diagram on the right.

15. Alkane Isomers CH 4 = methane, C 2 H 6 = ethane, C 3 H 8 = propane The molecular formula of an alkane with more than three carbons can give more than one structural isomer –C 4 H 10 –C 5 H 12

16. Constitutional Isomers Isomers that differ in how their atoms are arranged in chains are called constitutional isomers Compounds other than alkanes can be constitutional isomers of one another They must have the same molecular formula to be isomers

17. Alkyl Groups Alkyl group – remove one H from an alkane (a part of a structure) General abbreviation “R” (for Radical, an incomplete species or the “rest” of the molecule) Name: replace -ane ending of alkane with -yl ending – CH 3 is “methyl” (from methane) –CH 2 CH 3 is “ethyl” from ethane

18. Types of Alkyl groups Classified by the connection site a carbon at the end of a chain (primary alkyl group) –a carbon in the middle of a chain (secondary alkyl group) –a carbon with three carbons attached to it (tertiary alkyl group)

19. Naming Alkanes Compounds are given systematic names by a process that uses –Prefix-Parent-Suffix Follows specific rules –Named as longest possible chain –Carbons in that chain are numbered in sequence –substituents are numbered at their point of attachment –Compound name is one word (German style) –Complex substituents are named as compounds would be See specific examples in text

20. Nomenclature of Alkanes 1.Determine the number of carbons in the longest continuous chain 20

21. 2. Number the chain so that the substituent gets the lowest number 21

22. 3.Number the substituents to yield the lowest possible number in the number of the compound substituents are listed in alphabetical order 22

24. Cycloalkanes Cycloalkanes are alkanes that have carbon atoms that form a ring (called alicyclic compounds) Simple cycloalkanes rings of  CH2  units, (CH2)n, or CnH2n Structure is shown as a regular polygon with the number of vertices equal to the number of C’s (a projection of the actual structure) cyclopropane cyclohexanecyclopentane cyclobutane

25. Naming Cycloalkanes Count the number of carbon atoms in the ring and the number in the largest substituent chain. If the number of carbon atoms in the ring is equal to or greater than the number in the substituent, the compound is named as an alkyl-substituted cycloalkane For an alkyl- or halo-substituted cycloalkane, start at a point of attachment as C1 and number the substituents on the ring so that the second substituent has as low a number as possible. Number the substituents and write the name See text for more details and examples

26. Cis-Trans Isomerism in Cycloalkanes Rotation about C-C bonds in cycloalkanes is limited by the ring structure Rings have two “faces” and substituents are labeled as to their relative facial positions There are two different 1,2-dimethyl-cyclopropane isomers, one with the two methyls on the same side (cis) of the ring and one with the methyls on opposite sides (trans)

27. Amine groups NH 3 Primary amines: In primary amines, only one of the hydrogen atoms in the ammonia molecule has been replaced. That means that the formula of the primary amine will be RNH 2 where "R" is an alkyl group.

28. Secondary amines: In a secondary amine, two of the hydrogens in an ammonia molecule have been replaced by hydrocarbon groups. At this level, you are only likely to come across simple ones where both of the hydrocarbon groups are alkyl groups and both are the same.

29. Tertiary amines In a tertiary amine, all of the hydrogens in an ammonia molecule have been replaced by hydrocarbon groups. Again, you are only likely to come across simple ones where all three of the hydrocarbon groups are alkyl groups and all three are the same.

31. Stereoisomers is the study of molecules on space how atoms or groups in a molecule arranged in space relative to each other it is that part of the science which deals with structure in three dimensions

32.  Stereoisomerism 1.Optical active isomers. 2.Geometrical isomers. 3.Conformational isomers

33. 33 3.2: Conformational Analysis of Butane Staggered: anti Staggered: gauche 3 KJ/mol

34. Geometric isomerism An isomerism resulting from rigidity in molecules and accures only in two class of compounds alkenes and cyclic compounds σ – σ – bond free rotation ( flexibility )  - bond C = C no free rotation ( rigidity ) σ – bond restricted rotation ( semi-fexable )

36. Optical isomerism Optical isomerism occurs when substances have the same molecular and structural formulae, but one cannot be superimposed on the other. Put simply, they are mirror images of each other

37. (+)-lactic acid(–)-lactic acid The dashed lines show bonds going into the screen; the wedges show bonds coming out of the screen.

39. Triglycerides: Three Fatty Acids Dehydrated to One Glycerol Steroids Proteins(amino acids ) DNA