Chapter 13 rganic Chemistry-Part 2
13.4 Aromatic Compounds
Aromatic ydrocarbons Benzene (C66) was discovered in 1825, but a partially correct structure was not proposed until 1865 by August Kekule. The structure consisted of six carbons in a ring joined by alternating single and double bonds. Physical and chemical evidence indicates that benzene behaves as if all the carbon-carbon bonds are identical. ence, the following structural representation is sometimes used:
Delocalized Bonding in Benzene Sigma bonding system sp 2 hybrid orbitals Remaining p orbitals Delocalized π bonding
Aromatic ydrocarbons-nomenclature 1. Identify the benzene ring in a compound and assign the parent name benzene 2. Attach names and location of substituents. 3. For two or more substituents, number the benzene ring starting with one of the substituents to give the lowest combination of numbers to the substituents. 4. Some important monosubstituted benzenes have common names: C 3 N 2 C C Toluene Phenol Aniline Benzoic Acid Benzaldehyde
Aromatic ydrocarbons-nomenclature 5. The prefixes ortho (o), meta (m), and para (p) are often used to indicate the relative positions of two substituents in 1,2-, 1,3-, and 1,4- placement on a benzene ring. Br 1 Br Br 2 1 N 2 Br 1 3 Br N 2 4 1,2-dibromobenzene 1,3-dibromobenzene 1,4-dibromobenzene ortho-dibromobenzene meta-dibromobenzene para-dibromobenzene Br Cl
Name the following compounds as substituted benzenes. 15) 16) Cl C 2 C 3 1 4 3 1 3 Cl 2 N 2 Br 1-chloro-3-isopropyl benzene 2-bromo-1-chloro-5-ethyl-3-nitro benzene
The Benzene Ring in Drug Molecules C 3 C 3 C 3 C C 2 C 3 Aspirin Ibuprofen C 3 C 3 Cinnamedrine Dextromethorphan
13.5 Amines
Amines - Derivatives of Ammonia N Classification by the number of attached groups N N N ethylamine diethylamine triethylamine a primary amine a secondary amine a tertiary amine
Amines - Nomenclature Amines containing simple groups are named with common nomenclature. Simple groups include: Unbranched alkyl groups: methyl, ethyl, propyl, butyl,., decyl Branched 3- and 4-carbon alkyl groups: isopropyl, isobutyl, s-butyl, t-butyl Unsubstituted cycloalkyl groups: cyclohexyl and cyclopentyl C3 N C2 C3 ethylmethylamine N C3 C C3 2º 1º isopropylamine C3 N cyclohexylmethylamine C3 C3 2º 3º N C2C3 ethyldimethylamine
Amines - Basic Compounds When dissolved in water, amines generate hydroxide ions. N 4 + R R N + 2 R R=, alkyl, aryl R N + R R + - The product of the reaction is a salt and it is named from the name of the starting amine. C3 N methylamine + 2 C3 N + - + a solution of methylammonium hydroxide
Amines - Basic Compounds Ammonia may be reacted with a strong acid to quantitatively yield an amonium salt. N3 + Cl N4Cl ammonia hydrogen ammonium chloride chloride An amine may be reacted with a strong acid to quantitatively yield an amine salt. C3 N methylamine + Cl C3 N Cl- + methylammonium chloride
The Amino Group in Drug Molecules
Amines - Amine Based Drugs C 2C2 N C 3 Cl R-N + C3 Clphenylephrine hydrochloride NESYNEPRINE 3-(2-(methylamino)ethyl)phenol hydrochloride C 2 C 3 C C 2C2 N C 2 C 3 Cl C C 2 C 2 N C 3 Cl C 3 2 N procaine hydrochloride NVACAINE 2-(diethylamino)ethyl 4-aminobenzoate hydrochloride diphenehydramine hydrochloride BENADRYL 2-(benzhydryloxy)-N,N-dimethylethanamine hydrochloride
Biologically Interesting Amines
Biologically Interesting Amines
13.6 Alcohols and Ethers
Alcohols, Ethers, Phenols Structure of Functional Groups C C ALCL
Alcohols, Ethers, Phenols Structure of Functional Groups PENL C C C C ETER
Alcohols, Ethers, Phenols Structure of Functional Groups The oxygen atom in alcohols, phenols, and ethers is sp 3 hybridized. Two of the sp 3 orbitals are involved in bonding to hydrogen or carbon, and the remaining two contain lone-pair, or non-bonding, electrons. R R R water alcohol ether
Alcohols, Ethers, Phenols Structure of Functional Groups In water, the -- bond angle is 104.5 due to repulsion of the bonding electron pairs by the larger non-bonding electron pairs. In alcohols, phenols, and ethers the corresponding bond angles are closer to the expected tetrahedral 109.5 due to the replacement of one or both hydrogen atoms by larger carbon atoms.
Common Names Propyl alcohol (C3C2C2, propanol)
Isomerism in Alcohols 1-propanol 2-propanol
Nomenclature of Alcohols 1. Select the longest chain containing the - group as the parent chain; replace the -e with -ol 2. Number the parent chain starting at the end closest to the - group 3. Give the number for the position of the hydroxy group in front of the parent name. 1 2 3 5 C 2 C2 C 2 C2 C 3 4 1-pentanol 1 2 1 2 4 3 5 C 3 C2 C C2 C 3 3-pentanol 4 3 5 C 3 C C 2 C2 C 3 2-pentanol
4. Give the names and number of substituents 1 Cl C 3 2 C 4 C 3 C C 3 5 C 3 3-chloro-4-methyl-2-pentanol 5. Cyclic alcohols are named as cycloalkanols 6. If more than one alcohol group is present the terms diol, triol, etc. are used
Diols and Triols 1,2-ethanediol 1,2,3-propanetriol
Physical Properties of Alcohols-Boiling Points Boiling points increase with molecular weight and decrease with branching. Boiling points are higher than alkanes of similar molecular weight. 3 C 2 C C 2 3 C 2 C C 2 3 C 2 C C 2 3 C 2 C C 2 3 C 2 C C 2 3 C 2 C C 2 3 C 2 C C 2 3 C 2 C C 2 3 C 2 C C 2 3 C 2 C C 2 2 C 2 C C 2 C 2 C 3 2 C 2 C C 2 C 2 C 3 2 C 2 C C 2 C 2 C 3 2 C 2 C C 2 C 2 C 3 2 C 2 C C 2 C 2 C 3 2 C 2 C C 2 C 2 2 C 2 C C 2 C 2 C 2 C 2 2 C 2 C 2 C C 2 C 2 2 C 2 C 2 C C 2 C 2 ctane, boiling point = 126 C Attractive forces between alkane molecules are limited to simple London forces. eptanol, boiling point = 176 C Attractive forces between alcohol molecules include both dispersion forces and relatively strong hydrogen bonding.
Physical Properties of Alcohols-Solubility Alcohols are more water soluble than alkanes, but their water solubility is limited by the size of the nonpolar portion of the molecule. Nonpolar, or hydrophobic portions of molecules C 3 Polar, or hydrophilic portions of molecules 3 C C 2 C 2 C 2 C2 C 2 C 2
Physical Properties of Alcohols-Solubility C 3 C 3 TE RELATIVELY SMALL ATTRACTIN BETWEEN METANL MLECULES MAKES IT EASY FR WATER T SEPARATE INDIVIDUAL METANL MLECULES FRM EAC TER AND DISSLVE TE ALCL. METANL IS VERY SLUBLE IN WATER. TE RELATIVELY LARGE ATTRACTIN BETWEEN EPTANL MLECULES MAKES IT DIFFICULT FR WATER T SEPARATE INDIVIDUAL EPTANL MLECULES FRM EAC TER AND DISSLVE TE ALCL. EPTANL IS VERY SLIGTLY SLUBLE IN WATER. 3 C 3 C C 2 C 2 C 2 C 2 C2 C 2 C 2 C 2 C 2 C 2 C2 C 2
Solubilities of a omologous Series of Alcohols is Water
Functional Groups and Physical Properties
13.7 Carbonyl-Containing Compounds
Structure of the Carbonyl Group The carbonyl group is constructed in the same manner as the carboncarbon double bond, from an sp 2 hybridized carbon atom and an sp 2 hybridized oxygen atom. C The angles between the three bonds involved are approximately 120º.
Families Containing the Carbonyl Group Y C Z Family Y Z aldehyde or C ketone C C carboxylic acid or C -- ester or C --C amide or C -N
Nomenclature of Carbonyl Compounds Ethanal Propanone Ethanoic Acid Methyl ethanoate Ethanamide
Nomenclature of Carbonyl Compounds \\
Families Containing the Carbonyl Group
Aldehydes and Ketones
Common Aldehydes and Ketones C 2 Formaldehyde
Physical Properties of Aldehydes and Ketones Summary of Important Secondary Forces Which Contribute to boiling Points Alcohols Secondary Attractive Forces -bonding Dipole-dipole London ydrocarbons Aldehydes and Ketones Amines Increased Boiling Point
Physical Properties of Aldehydes and Ketones 240-200 - Boiling Point 160 120 - - Alcohols 80 40 - - Aldehydes Alkanes I I I I I 40 80 120 160 200 Molecular Mass
Physical Properties of Aldehydes Compound C C C 3 C 3 C 2 C C 3 C 2 C 2 C C C 3 C 2 C 2 C 2 Boiling Point (ºC) Water solubility (g/100 ml 2) -21 very soluble 21 very soluble 49 16 76 7 103 1
Physical Properties of Ketones Compound 3 C C C 3 C C 3 C 2 C3 C C 3 C 2 C 2 C3 C C 3 C 2 C 2 C 2 C3 Boiling Point (ºC) Water solubility (g/100 ml 2) 56 very soluble 80 26 102 6 127 - C 3 C 2 C 2 C 2 C 2 C C3 151 -
Carboxylic Acids and Derivatives
Polymers Polymer (macromolecule) a very large molecule with high molar mass formed by bonding together a large number of small molecules of low molecular mass. Monomer small molecule that bonds with others like it to form polymers. ligomer molecule that contain a few monomers; the middle ground between small molecules and polymers.
Addition Polymerization Monomers are added to the growing chain in such a manner so that all the atoms in the original monomers wind up in the chain. Condensation Polymerization Monomers are joined by removing small molecules from combining units. Each monomer has two reactive ends.
Addition Polymerization of Ethylenes verall Reaction: A X A X A X A X A X C=C C=C C=C C=C C=C B Y B Y B Y B Y B Y Acid or initiator A X A X A X A X A X C C C C C C C C C C B Y B Y B Y B Y B Y a polyethylene A X ( C C ) n n = number of individual units B Y
Addition Polymers from Ethylenes Monomer Polymer Uses C2 C2 (C2 C2 )n bottles, toys, housewares, wire cable insulation, plastic sheeting ethylene polyethylene C2 C (C2 C )n outdoor carpeting, food packaging appliance housings C3 C3 propylene polypropylene C2 C (C2 C )n styrofoam containers, food packaging hairbrush handles, toys styrene polystyrene
Addition Polymers from Ethylenes Monomer Polymer Uses C 2 C (C 2 C ) n home siding, gutters, flooring, garden hose, PVC tubing Cl Cl vinyl chloride polyvinylchloride (PVC) C 2 C (C 2 C ) n acrylic textile fibers CN CN acrylonitrile polyacrylonitrile polyacylonitrile CF2 CF2 tetrafluoroethylene (CF2 CF2 )n polytetrafluoroethylene Teflon, mechanical parts, cookware, chemical resistant gaskets
Condensation Polymers Polyesters Polyamides
Condensation Reactions Condensation reaction two molecules combining to form a larger molecule and a small molecule (typically water). 3 C C 2 C2 C C 3 3 C C 2 C2 C C 3 + 2 butanoic acid + methanol methyl butanoate C 2 C 3 C C2 butanoic acid + N ammonia 3 C C 2 C C2 N butanamide + 2
Condensation Reactions are also known by the term Dehydration Synthesis
Polyester Synthesis etc. Polyesters
Polyamide Synthesis etc. Nylons
13.8 Chirality
Stereochemistry - Review of Isomerism Isomers Structural Isomers Stereoisomers
Stereochemistry - Review of Isomerism Isomers Structural Isomers Stereoisomers Cis-trans Isomers Isomers with chiral centers
Stereochemistry - andedness in Everyday bjects We can imagine the mirror image of an object. In some cases, the mirror image and the original object are identical. In some cases, the mirror image and the original object are not identical.
Stereochemistry - andedness in rganic Compounds Enantiomers - compounds that have the following characteristics: 1) Molecules of two compounds are mirror images of each other. 2) Molecules of two compounds are nonsuperimposable. The characteristics of enantiomers are often the result of a single chiral carbon atom.
Stereochemistry - A Chiral Tetrahedral Carbon 1, 2, 3, and 4 must be different groups. What are different groups?
Stereochemistry - Examples of Enantiomers bromochlorofluoromethane
Stereochemistry - Examples of Enantiomers L-carvone D-carvone
Stereochemistry - Examples of Enantiomers 2-bromobutane
Chiral Recognition
Chiral Recognition Most reactions in living cells are catalyzed by protein molecules called enzymes. (Enzymes are a subset of a group of biological macromolecules referred to as receptors. ) Enzymes are large molecules containing a surface site, called the active site, where the substrate or reactant binds. For most enzymes this site is chiral. Chiral active sites are designed to interact strongly with one of the two possible substrate enantiomers, just as a left shoe interacts strongly with a left foot, and more or less excludes a right foot. This phenomenon is called chiral recognition or chiral discrimination. ther molecular properties are also used by enzymes to discriminate between substrate molecules: geometrical isomerism, size, shape, polarity, and charge. Discrimination on these bases is called the complementarity principle.
Chiral Recognition δ+ receptor response δ- δ- C δ- C N 2 2 C 3 δ+ (-) epinephrine (natural epinephrine) receptor active site
Chiral Recognition 3 C N 2 C 2 δ- δ- X C δ- δ+ δ+ X X receptor response (+) epinephrine Unnatural epinephrine) No receptor neurotransmitter complex forms