Introduc)on to Func)onal Groups in rganic Molecules CH 3 H 3 C N C C N C C N N CH CH 3 Caffeine
Func)onal Group Func%onal group - collec)on of atoms at a site that have a characteris)c behavior in all molecules where it occurs 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
Family and Func)onali)es in rganic Molecules Hydrocarbon Family Alkane Alkene Alkyne Arene Heteroatom- Subs)tuted Hydrocarbon Family Haloalkane or alkyl halide Alcohol Ether Amine Nitrile Nitro Sulfide Sulfoxide Sulfone Thiol Carbonyl Family Aldehyde Ketone Carboxylic Acid Acid chloride Anhydride Ester Lactone Amide Lactame
Alkanes, - H Alkanes: Compounds with C- C single bonds and C- H bonds only (no func)onal groups), non- polar molecule Easy to rotate around C- C single bonds Connec)ng 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 alipha%c compounds
Alkanes C 4 H 10 can be arranged in two ways: C 5 H 12 can be arranged in three ways: These are cons)tu)onal isomers: the same molecular formula but the atoms are linked differently.
Alkanes C 6 H 14 can be arranged in five ways:
Cons)tu)onal Isomers (Structural Isomers) Chain Different carbon chains Hexane and 2- Methylpentane Posi)onal Different posi)ons 2- Methylpentane 3- Methylpentane 1- Butanol and 2- Butanol Func)onal Group Different Func)onality Ethanol and dimethyl ether
Alkanes, - H Alkanes with C s connected to no more than 2 other C s are straight- chain or normal alkanes Alkanes with one or more C s connected to 3 or 4 C s are branched- chain alkanes Butane and pentane are straight- chain alkanes Isobutane, isopentane, and 2,2- dimethylpropane are branched- chain alkanes
Classifica)on of Carbons in a Molecule A primary carbon is bonded to one carbon. A secondary carbon is bonded to two carbons. A ter)ary carbon is bonded to three carbons. Primary hydrogens are a^ached to primary carbons. Secondary hydrogens are a^ached to secondary carbons. Ter)ary hydrogens are a^ached to ter)ary carbons.
Condensed Structures of Alkanes We can represent an alkane in a brief form or in many types of extended form A condensed structure does not show bonds but lists atoms, such as CH 3 CH 2 CH 2 CH 3 (butane) CH 3 (CH 2 ) 2 CH 3 (butane) Structural formulas
Condensed and Line Structures Condensed structure of Butane Line structure of Butane
Cycloalkanes, C n H 2n Bond Angles in Planar Cyclic Alkanes
Alkenes - Hydrocarbon With Carbon- Carbon Double Bond Also called an olefin but alkene is be^er Hydrocarbon that contains a C- C double bond, C n H 2n formula Unsaturated hydrocarbon, non- polar molecule No rota)on around C- C double bond, planar molecule Includes many naturally occurring materials Flavors, fragrances, vitamins
Classifica)on of Alkenes Ethene is the simplest alkene Subs)tu)ng one of the hydrogen from ethene by an alkyl group leads to monosubs)tuted alkene H H H CH 3 H H H H H H H Ethene Propene Monosubstitued alkene Disubs)tuted alkenes can be classified as H H H H H H Geminal trans cis
Classifica)on of Alkenes Trisubs)tuted alkene H Tetrasubs)tued alkene
Cycloalkenes, C n H 2n- 2 Cyclopropene Cyclobutene Cyclopenten Cyclohexene Cycloheptene Cyclooctene 1,4,5-Triethylcyclohex-1-ene
Molecules with More than one Double Bond If molecule has two double bonds, called diene If molecule has three double bonds, called triene Four double bonds called tetraene, and so on
Types of Dienes Diene can be classified as conjugated If they are separated by only one single bond they are conjugated and their orbitals interact The conjugated diene 1,3- butadiene has proper)es that are very different from those of the nonconjugated diene (isolated diene), 1,4- pentadiene.
Alkenes Classifica)on Classify the following alkenes:
Alkynes, C n H 2n- 2 Hydrocarbon that contains a C- C triple bond, C n H 2n- 2 formula Unsaturated hydrocarbon, non- polar molecule Ethyne, also known as acetylene with molecular formula C 2 H 2 Structure of Ethyne is Mono- subs)tuted alkyne or terminal alkyne H C C H r H C C CH 3 H C C CH(CH 3 ) 2 H C C
Alkynes, C n H 2n- 2 Di- subs)tuted alkyne or internal alkyne Internal alkyne can be symmetric or asymmetric H 3 C C C CH 3 (H 3 C) 2 HC C C CH(CH 3 ) 2 C C H 3 C C C CH(CH 3 ) 2 H 3 C C C C C '
Cycloalkynes Cycloalkyne starts with 8 or more carbons Cyclooctyne Cyclodecyne
Arene or Benzene, C 6 H 6 Unsaturated hydrocarbon Planar and non- polar molecule From high temperature dis)lla)on of coal tar Hea)ng petroleum at high temperature and pressure over a catalyst
Subs)tuted Benzenes Subs)tu)ng one hydrogen from benzene leads to monosubs)tuted arene Disubs)tuted benzenes 1,2-substituted ortho- or o- 1,3-substituted meta- or m- 1,4-substituted para- or p-
Subs)tuted Benzenes Trisubs)tuted benzenes 1,2,3- substituted Tetrasubs)tuted benzenes 1,2,4- substituted 1,3,5- substituted 1,2,3,4- substituted 1,2,4,5- substituted 1,2,3,5- substituted
Subs)tuted Benzenes nly one possible pentasubs)tuted benzene ne possible hexasubs)tuted benzene
Heteroatom- subs)tuted Hydrocarbons -H -Group where Group = halogen, H, SH, NH 2, CN
Haloalkanes or Alkyl halides, - X Carbon- halogen containing molecules Polar molecule - X where X = F, Cl, Br, I = alkyl or cycloalkyl Cl Cl
Classifica)on of Alkyl Halides Primary = Halogen is on a primary carbon Secondary = Halogen is on a secondary carbon Ter)ary = Halogen is on a ter)ary carbon
Alcohols, - H Carbon bonded to H group, known as Hydroxyl group Polar molecule Most alcohols are water insoluble except Methanol, Ethanol, Propan- 1- ol, Isopropyl alcohol, Butan- 1- ol H 3 C H H H H H
Classifica)on of Alcohols Primary alcohol = H is on a primary carbon Secondary alcohol = H is on a secondary carbon Ter)ary alcohol = H in on a ter)ary carbon
Ethers
Cyclic Ethers xirane xetane Tetrahydrofuran Tetrahydro-2H-pyran xepane xirane is also known as epoxide 2-Methyloxirane 2,2-Dimethyloxirane 3-Ethyl-2,2-dimethyloxirane
Classifica)on of Amines The classifica)on depends on how many groups are bonded to N. Primary amine Secondary amine = one group bonded to N = two groups bonded N Ter)ary amine = three groups bonded N
Amines versus Alkyl Halides and Alcohols
ther Nitrogen Containing Compounds, Nitrile Carbon bonded to cyano group, CN Polar molecule Nitrile can be reduced to primary amine Nitrile can be hydrolyzed to carboxylic acid Nitrile also called carboxylic acid deriva)ve C C N H 3 C CH 3 C C CH 3 N C N Nitrile Pivalonitrile
ther Nitrogen Containing Compounds,nitro Carbon bonded to nitro group Polar molecule Nitro group can be reduced to primary amine H C N 2 H C N 2 N 2 H Nitromethane
Sulfur Containing Molecoles Thiol, - S- H Sulfide, - S- symmetrical and - S- asymmetric Disulfide, - S- S- symmetric and - S- S- asymmetric Sulfonium salt, 3 S + X - Sulfide oxidezes to Sulfoxide and to Sulfone S Sulfoxide S Sulfone
Carbonyl Family Aldehydes and Ketones Carbonyl compounds with hydrogen and alkyl groups Formaldehyde: two hydrogen Aldehyde: a hydrogen and an alkyl group Ketone: two alkyl groups
Aldehydes and Ketones Found in Nature
Biologically Important Ketones
Carboxylic Acid and Deriva)ves A Carbonyl Group and An Acyl Group
Carboxylic Acids Carbon bonded to C 2 H group, known as carboxyl group Polar molecule Weak acids, pk a ~5 C C 2 H C 2 H H
Carboxylic Acids
Carboxylate Ion Salts Conjugate base of carboxylic acid is known as salt of carboxylic acid
Carboxylic Acid Deriva)ve, Ester Most esters have pleasant odor Esters can be obtained from carboxylic acids Polar molecule ' Ester Ethyl acetate Ethyl cyclohexanecarboxylate Ethyl benzoate
Cyclic Esters, Lactones
Carboxylic Acid Deriva)ve, Amide Amide are classified as Primary, Secondary and Ter)ary NH 2 NH' N 2 ' Primary Amide Secondary Amide Tertiary Amide
Amide
Cyclic Amides, Lactams
Carboxylic Acid Deriva)ve, Acid Halide
Carboxylic Acid Deriva)ve, Anhydride Anhydride can be symmetric or asymmetric symmetirc anhydride Acetic anhydride Benzoic anhydride ' asymmetirc anhydride Acetic benzoic anhydride Anhydride can be cyclic Decahydro-1H-benzo[c]oxecine-1,3(4H)-dione