Organic Chemistry

1. Organic Chemistry • Introduction • Functional Groups • Alkanes • Alkenes • Alkynes • Alcohols • Acids, Esters and Amides

2. Introduction • Organic chemistry is the study of carbon-containing compounds • The field of organic chemistry is very important for a wide variety of reasons. • A huge number of carbon-containing compounds are known. • Most of the advances in the pharmaceutical industry are based on a knowledge of organic chemistry. • Life as we know it is based on organic chemistry.

3. Introduction • Most organic compounds have a “skeleton” that is composed of C-C bonds. • The C-C bonds may be single bonds, double bonds, or triple bonds. • Carbon forms a total of 4 bonds. • The “skeleton” of an organic compound has H’s attached to it. • other “heteroatoms” like O, halogens, N, S, and P may be present as well

4. Introduction • Some familiar organic compounds: propane methane acetylene acetone

5. Introduction • Some familiar organic compounds: Acetic acid “ether” aspirin Ethyl alcohol

6. Introduction • Organic compounds are commonly classified and named based on the type of functional group present. • An atom or group of atoms that influences the way the molecule functions, reacts or behaves. • The center of reactivity in an organic compound

7. Functional Groups • On your exam, you will be responsible for recognizing and naming the various common functional groups that are found in organic compounds: • Use Table 25.4 and the following slides to help you study

8. Functional Groups

9. Functional Groups

10. Functional Groups

11. Alkanes • Contain C-C single bonds • no functional group • Tetrahedral electron domain geometry • sp3 hybridized carbons • Free rotation around single bonds propane

12. Cycloalkanes • Contain C – C with at least 3 of the carbons arranged in a cyclic (ring) structure • No functional group • Tetrahedral • sp3 hybrid orbitals

13. Alkyl Halides • Contain C-halogen bond • F, Cl, Br, or I

14. Alkenes • Contain C=C (carbon-carbon double bonds) • 1 sigma bond & 1 pi bond • Trigonal planar geometry • sp2 hybridized carbons Which atoms must be coplanar in an alkene? 1-propene

15. Alkenes • The C=C present in an alkene is composed of 1 sigma (s) bond and 1 pi (p) bond. • Double bonds are rigid and cannot rotate freely. • Rotation would cause loss of overlap of the p orbitals, destroying the p bond. ethylene

16. Alkynes • Contain C Ctriple bonds • 1 sigma bond • 2 pi bonds • Linear electron domain geometry • sp hybridized carbons Which atoms must be co-linear in an alkyne?

17. Aromatic Ring • Planar ring system with alternating single and double bonds • does not react like an alkene • Trigonal planar • sp2 hybridized carbons • Benzene ring is a very common aromatic ring. benzene pyridine

18. Functional Groups • Alkanes are often calledsaturated hydrocarbons • Organic compounds composed of carbon and hydrogen that contain the largest possible number of hydrogen atoms per carbon atom. • Alkenes, alkynes, and aromatic hydrocarbons are calledunsaturated hydrocarbons • Organic compounds composed of carbon and hydrogen that contain less hydrogen than an alkane having the same number of carbon atoms

19. Alcohols • Contain C-O-H bond • hydroxyl group • Alcohols form hydrogen bonds. • How does hydrogen bonding affect boiling point??? • Amphoteric

20. Ethers • Contain C-O-C bond • tetrahedrale.d. geometry • bent molecular geo.

21. Amines primary secondary tertiary • Contain C-N-R R’ • R and R’ can be H or C • Primary and secondary amines form hydrogen bonds. • Common organic bases • lone pair of e- on N

22. Aldehydes O C - H • Contain (-CHO) • Carbonyl (C=O) • always on the 1st or last carbon in a chain • trigonal planar geometry • sp2 hybrid orbitals

23. Ketones O C-C-C • Contain • Carbonyl attached to middle of chain • Trigonal planar e.d. geo. • sp2 hybridized C

24. Carboxylic Acids • Contain carboxyl group • Form hydrogen bonds • trigonal planar • sp2 hybridized carbon

25. Esters • Contain • trigonal planar • sp2 hybridized

26. Amides • Contain • where R and R’ = H or C • C=O is trigonal planar & sp2 hybridized

27. Nitriles • Contain • Linear • sp hybridized C

28. Functional Groups Example: Identify the functional groups present in the following compounds. thyroxine testosterone

29. Functional Groups Example:Identify the functional groups in the following compounds. Lisinopril Vanillin

30. Depicting Structures of Organic Compounds • Organic compounds can be depicted using a variety of formulas: • Empirical formula • Molecular formula • Lewis structure • Full structural formula • Three dimensional drawings • Condensed structural formula • Line angle drawings

31. Depicting Structures of Organic Compounds • Ethyl acetate is an organic molecule with: • empirical formula = C2H4O • molecular formula = C4H8O2

32. Depicting Structures of Organic Compounds • Ethyl acetate is an organic molecule with: • Lewis structure: • depicts all covalent bonds using a straight line and shows all nonbonding pairs of electrons • Full structural formula: • a Lewis structure without the nonbonding electrons

33. Depicting Structures of Organic Compounds • Ethyl acetate is an organic molecule with: • 3-d drawing: • Condensed structural formula • Line angle drawing

34. Alkanes Some of the simplest alkanes: You must know these!!!

35. Alkanes Some of the simplest alkanes: You must know these!!!

36. Alkanes • The previous alkanes are also called straight-chain hydrocarbons: • all of the carbon atoms are joined in a continuous chain • Alkanes containing 4 or more carbons can also form branched-chain hydrocarbons (branched hydrocarbons) • some of the carbon atoms form a “branch” or side-chain off of the main chain

37. Alkanes • An example of a straight chain hydrocarbon: • C5H12CH3CH2CH2CH2CH3pentane • Examples of a branched hydrocarbon: • C5H12CH3CHCH2CH3 CH3 CH3 CH3CCH3 CH3 2-methylbutane 2,2-dimethylpropane

38. Alkanes • The three structures shown previously for C5H12 are structural isomers: • compounds with the same molecular formula but different bonding arrangements • Structural isomers generally have different properties: • different melting points • different boiling points • often different chemical reactivity

39. Alkanes • Organic compounds can be named either using common names or IUPAC names. • You must be able to name alkanes, alkenes, alkynes, and alcohols with 10 or fewer carbons in the main chain using the IUPAC naming system.

40. Alkanes • Alkane Nomenclature: • Find the longest continuous chain of carbon atoms and use the name of the chain for the base name of the compound: • longest chain may not always be written in a straight line 1 2 CH3 - CH - CH3 CH2 - CH2 - CH2 - CH3 Base name: hexane 3 4 5 6

41. Alkanes • Alkane Nomenclature: • Number the carbon atoms in the longest chain beginning with the end of the chain closest to a substituent • groups attached to the main chain that have taken the place of a hydrogen atom on the main chain 1 A substituent 2 CH3 - CH - CH3 CH2 - CH2 - CH2 - CH3 3 4 5 6

42. Alkanes • Alkane Nomenclature: • Name and give the location of each substituent group • A substituent group that is formed by removing an H atom from an alkane is called analkyl group: • Name alkyl groups by dropping the “ane” ending of the parent alkane and adding “yl”

43. Alkanes • Alkane Nomenclature: • Common alkyl groups (substituents): CH3 methyl CH3CH2 ethyl CH3CH2CH2 propyl CH3CH2CH2CH2 butyl Know these! 1 2 CH3 - CH - CH3 CH2 - CH2 - CH2 - CH3 3 4 5 6 2-methylhexane

44. Alkanes • Alkane Nomenclature: • Halogen atoms are another common class of substituents. • Name halogen substituents as “halo”: • Cl chloro • Br bromo • I iodo • F fluoro

45. Alkanes • Alkane Nomenclature: • When two or more substituents are present, list them in alphabetical order: • Butyl vs. ethyl vs. methyl vs. propyl • When more than one of the same substituent is present (i.e. two methyl groups), use prefixes to indicate the number: • Di = two • Tri = three • Tetra = four • Penta = five Know these.

46. Alkanes Example: Name the following compounds: CH3CH2CHCH2CH3 CH3 CH2CH2CH3 CH3CHCHCH3 CH3

47. Alkanes Example: Name the following compounds: CH3CH2CHCH3 CH2CH2Br CH2CH2CH3 CH3CHCHCH3 Cl

48. Alkanes • You must also be able to write the structure of an alkane when given the IUPAC name. • To do so: • Identify the main chain and draw the carbons in it • Identify the substituents (type and #) and attach them to the appropriate carbon atoms on the main chain. • Add hydrogen atoms to the carbons to make a total of 4 bonds to each carbon

49. Alkanes Example: Write the condensed structure for the following compounds: 3, 3-dimethylpentane 3-ethyl-2-methylhexane 2-methyl-4-propyloctane 1, 2-dichloro-3-methylheptane

50. Alkenes • Alkenes: • unsaturated hydrocarbons that contain a C=C double bond • Alkene Nomenclature: • Names of alkenes are based on the longest continuous chain of carbon atoms that contains the double bond.