net Structures of Common Coenzymes The reactive parts of the molecules are darkened, while nonreactive parts are ghosted. Adenosine triphosphate—ATP (phosphorylation) NH2 N N O O O –O P O P O P OCH2 N N O O– O– O– OH OH www.net Coenzyme A (acyl transfer) NH2 N N O O CH3 O O HSCH2CH2NHCCH2CH2NHCCHCCH2OPOPOCH2 N N O HO CH3 O– O– 2–O PO OH 3 Nicotinamide adenine dinucleotide—NAD+ (oxidation/reduction) (NADP+) NH2 CONH2 N N O O N CH2OPOPOCH2 N N + O OH HO O– O– O OH OH (OPO32–) Flavin adenine dinucleotide—FAD (oxidation/reduction) NH2 N N HO OH O O HO CHCHCHCH2OPOPOCH2 N N O CH2 O– O– H3C N N O OH OH N H3C N H O www.net Tetrahydrofolate (transfer of C1 units) H H2N N N H N N H N CO2– O H O H NHCHCH2CH2C O– 1–5 O www.net S-Adenosylmethionine (methyl transfer) NH2 N N O CH3 –OCCHCH CH S CH2 N 2 2 + N O +NH 3 OH OH Lipoic acid (acyl transfer) Pyridoxal phosphate (amino acid metabolism) S S CH2OPO32– CHO CH2CH2CH2CH2CO2– + N H OH CH3 Thiamin diphosphate Biotin (carboxylation) (decarboxylation) H NH2 O + H H S N N N N O O H H –OPOPOCH CH CH3 N CH3 H 2 2 S CH2CH2CH2CH2CO2– O– O– www.net s, even Dear Colleague: t of th e st ud en ts in our course know that mos in pure te ac h or ganic chemistry e li fe sc ie nces rather than All of us w ho terested primar ily in th doctors ar e in ts , bi ochemists, and www.net y m aj or s, re bi ol og is we the chemistr ar e te ac hing so many fu tu us ar e questioning why se w e m or e of chemistry. Becau ves, more and the details of an yo un ge r ve rsions of oursel sp en d so m uc h time discussing ogy? Why rather th e nnection to biol ac h th e w ay w e do. Why do w t ha ve li tt le co continue to te ch chemists bu ng organisms? ons th at are of interest to resear ng the or ga ni c chemistry of livi reacti me discussi t it is d spend more ti aditional way, bu don’t we instea organic chem is tr y in th e tr who want to m uc h to be sa id for teaching rn at iv e fo r th ose instructors There is stil l al te gical l no w th er e has been no real rg an ic C he m istry with Biolo also true that un ti O and er en tl y. A nd th at is why I wrote om in en ce , I su spect that more t diff s to gain in pr teach somewha ic al biology continue A s ch em cordingly. gi ng their teaching ac ciple in more faculty wil l be ch an ch em is tr y. B ut my guiding prin on organic clusively on ta ke : th is is still a textbook s be en to focus almost ex Make no m is e ou t ha saved by t to in cl ud e and what to leav ol og ic al ch em istry. The space deciding w ha counterpart in bi every reaction on s th at have a direct to go od use, for almost voted thos e re ac ti gi ca l re ac tion s has be en pu t im at el y 25 % of the book is de io lo ple and approx addition, leaving out nonb by a biological exam bi otra nsformations. In fo ll ow ed istr y of th ei r andard discussed is es an d the organic chem 0 pa ge s shorter than st ol ec ul ne ar ly 20 urse. entirely to biom h B io lo gica l Applications is in a ty pi ca l two-semester co try w it the entire bo ok Organic Chemis faculty to cover ss ib le fo r text; I believe texts, making it po s is di ff er en t from any other l Application an ic C he m is tr y with Biologica Org ts. r today’s studen that it is ideal fo Sincerely, John McMurry All royalties from Organic Chemistry with Biological Applications will be donated to the Cystic Fibrosis (CF) Foundation. This book and donation are dedicated to the author’s eldest son and to the thousands of others who daily fight this disease. To learn more about CF and the programs and services provided by the CF Foundation, please visit http://www.net This page intentionally left blank www.net Organic Chemistry with Biological Applications 2e John McMurry Cornell University Australia • Brazil • Japan • Korea • Mexico • Singapore • Spain • United Kingdom • United States www.net Organic Chemistry with Biological © 2011, 2007 Brooks/Cole, Cengage Learning Applications 2e ALL RIGHTS RESERVED. 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Printed in Canada 1 2 3 4 5 6 7 13 12 11 10 09 www.net Brief Contents 1 Structure and Bonding 1 2 Polar Covalent Bonds; Acids and Bases 33 3 Organic Compounds: Alkanes and Their Stereochemistry 70 4 Organic Compounds: Cycloalkanes and Their Stereochemistry 105 5 Stereochemistry at Tetrahedral Centers 134 6 An Overview of Organic Reactions 175 7 Alkenes and Alkynes 212 8 Reactions of Alkenes and Alkynes 251 www.net 9 Aromatic Compounds 309 10 Structure Determination: Mass Spectrometry, Infrared Spectroscopy, and Ultraviolet Spectroscopy 367 11 Structure Determination: Nuclear Magnetic Resonance Spectroscopy 404 12 Organohalides: Nucleophilic Substitutions and Eliminations 444 13 Alcohols, Phenols, and Thiols; Ethers and Sulfides 501 Preview of Carbonyl Chemistry 555 14 Aldehydes and Ketones: Nucleophilic Addition Reactions 564 15 Carboxylic Acids and Nitriles 610 16 Carboxylic Acid Derivatives: Nucleophilic Acyl Substitution Reactions 643 17 Carbonyl Alpha-Substitution and Condensation Reactions 695 18 Amines and Heterocycles 749 19 Biomolecules: Amino Acids, Peptides, and Proteins 791 20 Amino Acid Metabolism 832 21 Biomolecules: Carbohydrates 862 22 Carbohydrate Metabolism 901 23 Biomolecules: Lipids and Their Metabolism 936 24 Biomolecules: Nucleic Acids and Their Metabolism 987 25 Secondary Metabolites: An Introduction to Natural Products Chemistry 1015 Key to Sequence of Topics (chapter numbers are color coded as follows): • Traditional foundations of organic chemistry • Organic reactions and their biological counterparts • The organic chemistry of biological molecules and pathways v www.net Detailed Contents www.net 1 Structure and Bonding 1 1.1 Atomic Structure: The Nucleus 3 1.2 Atomic Structure: Orbitals 4 1.3 Atomic Structure: Electron Configurations 6 1.4 Development of Chemical Bonding Theory 7 1.5 The Nature of Chemical Bonds: Valence Bond Theory 10 1.6 sp3 Hybrid Orbitals and the Structure of Methane 12 1.7 sp3 Hybrid Orbitals and the Structure of Ethane 13 1.8 sp2 Hybrid Orbitals and the Structure of Ethylene 14 1.9 sp Hybrid Orbitals and the Structure of Acetylene 17 1.10 Hybridization of Nitrogen, Oxygen, Phosphorus, and Sulfur 18 1.11 The Nature of Chemical Bonds: Molecular Orbital Theory 20 1.12 Drawing Chemical Structures 21 Summary 24 Lagniappe—Chemicals, Toxicity, and Risk 25 Working Problems 26 Exercises 26 2 Polar Covalent Bonds; Acids and Bases 33 2.1 Polar Covalent Bonds: Electronegativity 33 2.2 Polar Covalent Bonds: Dipole Moments 36 2.5 Rules for Resonance Forms 43 2.6 Drawing Resonance Forms 45 2.7 Acids and Bases: The Brønsted–Lowry Definition 48 vi www.net detailed contents vii 2.8 Acid and Base Strength 49 2.9 Predicting Acid–Base Reactions from pKa Values 51 2.10 Organic Acids and Organic Bases 53 2.11 Acids and Bases: The Lewis Definition 56 2.12 Noncovalent Interactions between Molecules 60 Summary 62 Lagniappe—Alkaloids: Naturally Occurring Bases 63 Exercises 64 Organic Compounds: Alkanes and Their 3 Stereochemistry 70 www.2 Alkanes and Alkane Isomers 77 3.5 Properties of Alkanes 89 3.6 Conformations of Ethane 90 3.7 Conformations of Other Alkanes 92 Summary 97 Lagniappe—Gasoline 98 Exercises 99 Organic Compounds: Cycloalkanes and Their 4 Stereochemistry 105 4.2 Cis–Trans Isomerism in Cycloalkanes 109 4.3 Stability of Cycloalkanes: Ring Strain 112 4.4 Conformations of Cycloalkanes 113 4.5 Conformations of Cyclohexane 115 4.6 Axial and Equatorial Bonds in Cyclohexane 117 4.7 Conformations of Monosubstituted Cyclohexanes 120 4.8 Conformations of Disubstituted Cyclohexanes 123 4.9 Conformations of Polycyclic Molecules 126 Summary 127 Lagniappe—Molecular Mechanics 128 Exercises 129 www.net viii detailed contents 5 Stereochemistry at Tetrahedral Centers 134 5.1 Enantiomers and the Tetrahedral Carbon 135 5.2 The Reason for Handedness in Molecules: Chirality 136 5.4 Pasteur’s Discovery of Enantiomers 142 5.5 Sequence Rules for Specifying Configuration 143 5.8 Racemic Mixtures and the Resolution of Enantiomers 154 5.9 A Review of Isomerism 156 5.10 Chirality at Nitrogen, Phosphorus, and Sulfur 158 5.12 Chirality in Nature and Chiral Environments 162 www.net Summary 164 Lagniappe—Chiral Drugs 165 Exercises 166 6 An Overview of Organic Reactions 175 6.1 Kinds of Organic Reactions 176 6.2 How Organic Reactions Occur: Mechanisms 177 6.5 An Example of a Polar Reaction: Addition of H2O to Ethylene 186 6.6 Using Curved Arrows in Polar Reaction Mechanisms 189 6.7 Describing a Reaction: Equilibria, Rates, and Energy Changes 192 6.8 Describing a Reaction: Bond Dissociation Energies 195 6.9 Describing a Reaction: Energy Diagrams and Transition States 197 6.10 Describing a Reaction: Intermediates 200 6.11 A Comparison between Biological Reactions and Laboratory Reactions 202 Summary 204 Lagniappe—Where Do Drugs Come From? 205 Exercises 206 7 Alkenes and Alkynes 212 7.1 Calculating a Degree of Unsaturation 213 7.2 Naming Alkenes and Alkynes 216 7.3 Cis–Trans Isomerism in Alkenes 219 7.4 Alkene Stereochemistry and the E,Z Designation 221 7.5 Stability of Alkenes 223 www.net detailed contents ix 7.6 Electrophilic Addition Reactions of Alkenes 227 Writing Organic Reactions 229 7.7 Orientation of Electrophilic Addition: Markovnikov’s Rule 230 7.