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Organic Chemistry

Additional Problems

Organic ChemistryAdditional Problems

Table of contents
  1. Dedication and Preface
  2. 1 Structure and Bonding
    1. Why This Chapter?
    2. 1.1 Atomic Structure: The Nucleus
    3. 1.2 Atomic Structure: Orbitals
    4. 1.3 Atomic Structure: Electron Configurations
    5. 1.4 Development of Chemical Bonding Theory
    6. 1.5 Describing Chemical Bonds: Valence Bond Theory
    7. 1.6 sp3 Hybrid Orbitals and the Structure of Methane
    8. 1.7 sp3 Hybrid Orbitals and the Structure of Ethane
    9. 1.8 sp2 Hybrid Orbitals and the Structure of Ethylene
    10. 1.9 sp Hybrid Orbitals and the Structure of Acetylene
    11. 1.10 Hybridization of Nitrogen, Oxygen, Phosphorus, and Sulfur
    12. 1.11 Describing Chemical Bonds: Molecular Orbital Theory
    13. 1.12 Drawing Chemical Structures
    14. Chemistry Matters—Organic Foods: Risk versus Benefit
    15. Key Terms
    16. Summary
    17. Additional Problems
  3. 2 Polar Covalent Bonds; Acids and Bases
    1. Why This Chapter?
    2. 2.1 Polar Covalent Bonds and Electronegativity
    3. 2.2 Polar Covalent Bonds and Dipole Moments
    4. 2.3 Formal Charges
    5. 2.4 Resonance
    6. 2.5 Rules for Resonance Forms
    7. 2.6 Drawing Resonance Forms
    8. 2.7 Acids and Bases: The Brønsted–Lowry Definition
    9. 2.8 Acid and Base Strength
    10. 2.9 Predicting Acid–Base Reactions from pKa Values
    11. 2.10 Organic Acids and Organic Bases
    12. 2.11 Acids and Bases: The Lewis Definition
    13. 2.12 Noncovalent Interactions between Molecules
    14. Chemistry Matters—Alkaloids: From Cocaine to Dental Anesthetics
    15. Key Terms
    16. Summary
    17. Additional Problems
  4. 3 Organic Compounds: Alkanes and Their Stereochemistry
    1. Why This Chapter?
    2. 3.1 Functional Groups
    3. 3.2 Alkanes and Alkane Isomers
    4. 3.3 Alkyl Groups
    5. 3.4 Naming Alkanes
    6. 3.5 Properties of Alkanes
    7. 3.6 Conformations of Ethane
    8. 3.7 Conformations of Other Alkanes
    9. Chemistry Matters—Gasoline
    10. Key Terms
    11. Summary
    12. Additional Problems
  5. 4 Organic Compounds: Cycloalkanes and Their Stereochemistry
    1. Why This Chapter?
    2. 4.1 Naming Cycloalkanes
    3. 4.2 Cis–Trans Isomerism in Cycloalkanes
    4. 4.3 Stability of Cycloalkanes: Ring Strain
    5. 4.4 Conformations of Cycloalkanes
    6. 4.5 Conformations of Cyclohexane
    7. 4.6 Axial and Equatorial Bonds in Cyclohexane
    8. 4.7 Conformations of Monosubstituted Cyclohexanes
    9. 4.8 Conformations of Disubstituted Cyclohexanes
    10. 4.9 Conformations of Polycyclic Molecules
    11. Chemistry Matters—Molecular Mechanics
    12. Key Terms
    13. Summary
    14. Additional Problems
  6. 5 Stereochemistry at Tetrahedral Centers
    1. Why This Chapter?
    2. 5.1 Enantiomers and the Tetrahedral Carbon
    3. 5.2 The Reason for Handedness in Molecules: Chirality
    4. 5.3 Optical Activity
    5. 5.4 Pasteur’s Discovery of Enantiomers
    6. 5.5 Sequence Rules for Specifying Configuration
    7. 5.6 Diastereomers
    8. 5.7 Meso Compounds
    9. 5.8 Racemic Mixtures and the Resolution of Enantiomers
    10. 5.9 A Review of Isomerism
    11. 5.10 Chirality at Nitrogen, Phosphorus, and Sulfur
    12. 5.11 Prochirality
    13. 5.12 Chirality in Nature and Chiral Environments
    14. Chemistry Matters—Chiral Drugs
    15. Key Terms
    16. Summary
    17. Additional Problems
  7. 6 An Overview of Organic Reactions
    1. Why This Chapter?
    2. 6.1 Kinds of Organic Reactions
    3. 6.2 How Organic Reactions Occur: Mechanisms
    4. 6.3 Polar Reactions
    5. 6.4 An Example of a Polar Reaction: Addition of HBr to Ethylene
    6. 6.5 Using Curved Arrows in Polar Reaction Mechanisms
    7. 6.6 Radical Reactions
    8. 6.7 Describing a Reaction: Equilibria, Rates, and Energy Changes
    9. 6.8 Describing a Reaction: Bond Dissociation Energies
    10. 6.9 Describing a Reaction: Energy Diagrams and Transition States
    11. 6.10 Describing a Reaction: Intermediates
    12. 6.11 A Comparison Between Biological Reactions and Laboratory Reactions
    13. Chemistry Matters—Where Do Drugs Come From?
    14. Key Terms
    15. Summary
    16. Additional Problems
  8. 7 Alkenes: Structure and Reactivity
    1. Why This Chapter?
    2. 7.1 Industrial Preparation and Use of Alkenes
    3. 7.2 Calculating the Degree of Unsaturation
    4. 7.3 Naming Alkenes
    5. 7.4 Cis–Trans Isomerism in Alkenes
    6. 7.5 Alkene Stereochemistry and the E,Z Designation
    7. 7.6 Stability of Alkenes
    8. 7.7 Electrophilic Addition Reactions of Alkenes
    9. 7.8 Orientation of Electrophilic Additions: Markovnikov’s Rule
    10. 7.9 Carbocation Structure and Stability
    11. 7.10 The Hammond Postulate
    12. 7.11 Evidence for the Mechanism of Electrophilic Additions: Carbocation Rearrangements
    13. Chemistry Matters—Bioprospecting: Hunting for Natural Products
    14. Key Terms
    15. Summary
    16. Additional Problems
  9. 8 Alkenes: Reactions and Synthesis
    1. Why This Chapter?
    2. 8.1 Preparing Alkenes: A Preview of Elimination Reactions
    3. 8.2 Halogenation of Alkenes: Addition of X2
    4. 8.3 Halohydrins from Alkenes: Addition of HO-X
    5. 8.4 Hydration of Alkenes: Addition of H2O by Oxymercuration
    6. 8.5 Hydration of Alkenes: Addition of H2O by Hydroboration
    7. 8.6 Reduction of Alkenes: Hydrogenation
    8. 8.7 Oxidation of Alkenes: Epoxidation and Hydroxylation
    9. 8.8 Oxidation of Alkenes: Cleavage to Carbonyl Compounds
    10. 8.9 Addition of Carbenes to Alkenes: Cyclopropane Synthesis
    11. 8.10 Radical Additions to Alkenes: Chain-Growth Polymers
    12. 8.11 Biological Additions of Radicals to Alkenes
    13. 8.12 Reaction Stereochemistry: Addition of H2O to an Achiral Alkene
    14. 8.13 Reaction Stereochemistry: Addition of H2O to a Chiral Alkene
    15. Chemistry Matters—Terpenes: Naturally Occurring Alkenes
    16. Key Terms
    17. Summary
    18. Summary of Reactions
    19. Additional Problems
  10. 9 Alkynes: An Introduction to Organic Synthesis
    1. Why This Chapter?
    2. 9.1 Naming Alkynes
    3. 9.2 Preparation of Alkynes: Elimination Reactions of Dihalides
    4. 9.3 Reactions of Alkynes: Addition of HX and X2
    5. 9.4 Hydration of Alkynes
    6. 9.5 Reduction of Alkynes
    7. 9.6 Oxidative Cleavage of Alkynes
    8. 9.7 Alkyne Acidity: Formation of Acetylide Anions
    9. 9.8 Alkylation of Acetylide Anions
    10. 9.9 An Introduction to Organic Synthesis
    11. Chemistry Matters—The Art of Organic Synthesis
    12. Key Terms
    13. Summary
    14. Summary of Reactions
    15. Additional Problems
  11. 10 Organohalides
    1. Why This Chapter?
    2. 10.1 Names and Structures of Alkyl Halides
    3. 10.2 Preparing Alkyl Halides from Alkanes: Radical Halogenation
    4. 10.3 Preparing Alkyl Halides from Alkenes: Allylic Bromination
    5. 10.4 Stability of the Allyl Radical: Resonance Revisited
    6. 10.5 Preparing Alkyl Halides from Alcohols
    7. 10.6 Reactions of Alkyl Halides: Grignard Reagents
    8. 10.7 Organometallic Coupling Reactions
    9. 10.8 Oxidation and Reduction in Organic Chemistry
    10. Chemistry Matters—Naturally Occurring Organohalides
    11. Key Terms
    12. Summary
    13. Summary of Reactions
    14. Additional Problems
  12. 11 Reactions of Alkyl Halides: Nucleophilic Substitutions and Eliminations
    1. Why This Chapter?
    2. 11.1 The Discovery of Nucleophilic Substitution Reactions
    3. 11.2 The SN2 Reaction
    4. 11.3 Characteristics of the SN2 Reaction
    5. 11.4 The SN1 Reaction
    6. 11.5 Characteristics of the SN1 Reaction
    7. 11.6 Biological Substitution Reactions
    8. 11.7 Elimination Reactions: Zaitsev’s Rule
    9. 11.8 The E2 Reaction and the Deuterium Isotope Effect
    10. 11.9 The E2 Reaction and Cyclohexane Conformation
    11. 11.10 The E1 and E1cB Reactions
    12. 11.11 Biological Elimination Reactions
    13. 11.12 A Summary of Reactivity: SN1, SN2, E1, E1cB, and E2
    14. Chemistry Matters—Green Chemistry
    15. Key Terms
    16. Summary
    17. Summary of Reactions
    18. Additional Problems
  13. 12 Structure Determination: Mass Spectrometry and Infrared Spectroscopy
    1. Why This Chapter?
    2. 12.1 Mass Spectrometry of Small Molecules: Magnetic-Sector Instruments
    3. 12.2 Interpreting Mass Spectra
    4. 12.3 Mass Spectrometry of Some Common Functional Groups
    5. 12.4 Mass Spectrometry in Biological Chemistry: Time-of-Flight (TOF) Instruments
    6. 12.5 Spectroscopy and the Electromagnetic Spectrum
    7. 12.6 Infrared Spectroscopy
    8. 12.7 Interpreting Infrared Spectra
    9. 12.8 Infrared Spectra of Some Common Functional Groups
    10. Chemistry Matters—X-Ray Crystallography
    11. Key Terms
    12. Summary
    13. Additional Problems
  14. 13 Structure Determination: Nuclear Magnetic Resonance Spectroscopy
    1. Why This Chapter?
    2. 13.1 Nuclear Magnetic Resonance Spectroscopy
    3. 13.2 The Nature of NMR Absorptions
    4. 13.3 Chemical Shifts
    5. 13.4 Chemical Shifts in 1H NMR Spectroscopy
    6. 13.5 Integration of 1H NMR Absorptions: Proton Counting
    7. 13.6 Spin–Spin Splitting in 1H NMR Spectra
    8. 13.7 1H NMR Spectroscopy and Proton Equivalence
    9. 13.8 More Complex Spin–Spin Splitting Patterns
    10. 13.9 Uses of 1H NMR Spectroscopy
    11. 13.10 13C NMR Spectroscopy: Signal Averaging and FT–NMR
    12. 13.11 Characteristics of 13C NMR Spectroscopy
    13. 13.12 DEPT 13C NMR Spectroscopy
    14. 13.13 Uses of 13C NMR Spectroscopy
    15. Chemistry Matters—Magnetic Resonance Imaging (MRI)
    16. Key Terms
    17. Summary
    18. Additional Problems
  15. 14 Conjugated Compounds and Ultraviolet Spectroscopy
    1. Why This Chapter?
    2. 14.1 Stability of Conjugated Dienes: Molecular Orbital Theory
    3. 14.2 Electrophilic Additions to Conjugated Dienes: Allylic Carbocations
    4. 14.3 Kinetic versus Thermodynamic Control of Reactions
    5. 14.4 The Diels–Alder Cycloaddition Reaction
    6. 14.5 Characteristics of the Diels–Alder Reaction
    7. 14.6 Diene Polymers: Natural and Synthetic Rubbers
    8. 14.7 Ultraviolet Spectroscopy
    9. 14.8 Interpreting Ultraviolet Spectra: The Effect of Conjugation
    10. 14.9 Conjugation, Color, and the Chemistry of Vision
    11. Chemistry Matters—Photolithography
    12. Key Terms
    13. Summary
    14. Summary of Reactions
    15. Additional Problems
  16. 15 Benzene and Aromaticity
    1. Why This Chapter?
    2. 15.1 Naming Aromatic Compounds
    3. 15.2 Structure and Stability of Benzene
    4. 15.3 Aromaticity and the Hückel 4n + 2 Rule
    5. 15.4 Aromatic Ions
    6. 15.5 Aromatic Heterocycles: Pyridine and Pyrrole
    7. 15.6 Polycyclic Aromatic Compounds
    8. 15.7 Spectroscopy of Aromatic Compounds
    9. Chemistry Matters—Aspirin, NSAIDs, and COX-2 Inhibitors
    10. Key Terms
    11. Summary
    12. Additional Problems
  17. 16 Chemistry of Benzene: Electrophilic Aromatic Substitution
    1. Why This Chapter?
    2. 16.1 Electrophilic Aromatic Substitution Reactions: Bromination
    3. 16.2 Other Aromatic Substitutions
    4. 16.3 Alkylation and Acylation of Aromatic Rings: The Friedel–Crafts Reaction
    5. 16.4 Substituent Effects in Electrophilic Substitutions
    6. 16.5 Trisubstituted Benzenes: Additivity of Effects
    7. 16.6 Nucleophilic Aromatic Substitution
    8. 16.7 Benzyne
    9. 16.8 Oxidation of Aromatic Compounds
    10. 16.9 Reduction of Aromatic Compounds
    11. 16.10 Synthesis of Polysubstituted Benzenes
    12. Chemistry Matters—Combinatorial Chemistry
    13. Key Terms
    14. Summary
    15. Summary of Reactions
    16. Additional Problems
  18. 17 Alcohols and Phenols
    1. Why This Chapter?
    2. 17.1 Naming Alcohols and Phenols
    3. 17.2 Properties of Alcohols and Phenols
    4. 17.3 Preparation of Alcohols: A Review
    5. 17.4 Alcohols from Carbonyl Compounds: Reduction
    6. 17.5 Alcohols from Carbonyl Compounds: Grignard Reaction
    7. 17.6 Reactions of Alcohols
    8. 17.7 Oxidation of Alcohols
    9. 17.8 Protection of Alcohols
    10. 17.9 Phenols and Their Uses
    11. 17.10 Reactions of Phenols
    12. 17.11 Spectroscopy of Alcohols and Phenols
    13. Chemistry Matters—Ethanol: Chemical, Drug, and Poison
    14. Key Terms
    15. Summary
    16. Summary of Reactions
    17. Additional Problems
  19. 18 Ethers and Epoxides; Thiols and Sulfides
    1. Why This Chapter?
    2. 18.1 Names and Properties of Ethers
    3. 18.2 Preparing Ethers
    4. 18.3 Reactions of Ethers: Acidic Cleavage
    5. 18.4 Cyclic Ethers: Epoxides
    6. 18.5 Reactions of Epoxides: Ring-Opening
    7. 18.6 Crown Ethers
    8. 18.7 Thiols and Sulfides
    9. 18.8 Spectroscopy of Ethers
    10. Chemistry Matters—Epoxy Resins and Adhesives
    11. Key Terms
    12. Summary
    13. Summary of Reactions
    14. Additional Problems
    15. Preview of Carbonyl Chemistry
  20. 19 Aldehydes and Ketones: Nucleophilic Addition Reactions
    1. Why This Chapter?
    2. 19.1 Naming Aldehydes and Ketones
    3. 19.2 Preparing Aldehydes and Ketones
    4. 19.3 Oxidation of Aldehydes and Ketones
    5. 19.4 Nucleophilic Addition Reactions of Aldehydes and Ketones
    6. 19.5 Nucleophilic Addition of H2O: Hydration
    7. 19.6 Nucleophilic Addition of HCN: Cyanohydrin Formation
    8. 19.7 Nucleophilic Addition of Hydride and Grignard Reagents: Alcohol Formation
    9. 19.8 Nucleophilic Addition of Amines: Imine and Enamine Formation
    10. 19.9 Nucleophilic Addition of Hydrazine: The Wolff–Kishner Reaction
    11. 19.10 Nucleophilic Addition of Alcohols: Acetal Formation
    12. 19.11 Nucleophilic Addition of Phosphorus Ylides: The Wittig Reaction
    13. 19.12 Biological Reductions
    14. 19.13 Conjugate Nucleophilic Addition to α,β‑Unsaturated Aldehydes and Ketones
    15. 19.14 Spectroscopy of Aldehydes and Ketones
    16. Chemistry Matters—Enantioselective Synthesis
    17. Key Terms
    18. Summary
    19. Summary of Reactions
    20. Additional Problems
  21. 20 Carboxylic Acids and Nitriles
    1. Why This Chapter?
    2. 20.1 Naming Carboxylic Acids and Nitriles
    3. 20.2 Structure and Properties of Carboxylic Acids
    4. 20.3 Biological Acids and the Henderson–Hasselbalch Equation
    5. 20.4 Substituent Effects on Acidity
    6. 20.5 Preparing Carboxylic Acids
    7. 20.6 Reactions of Carboxylic Acids: An Overview
    8. 20.7 Chemistry of Nitriles
    9. 20.8 Spectroscopy of Carboxylic Acids and Nitriles
    10. Chemistry Matters—Vitamin C
    11. Key Terms
    12. Summary
    13. Summary of Reactions
    14. Additional Problems
  22. 21 Carboxylic Acid Derivatives: Nucleophilic Acyl Substitution Reactions
    1. Why This Chapter?
    2. 21.1 Naming Carboxylic Acid Derivatives
    3. 21.2 Nucleophilic Acyl Substitution Reactions
    4. 21.3 Reactions of Carboxylic Acids
    5. 21.4 Chemistry of Acid Halides
    6. 21.5 Chemistry of Acid Anhydrides
    7. 21.6 Chemistry of Esters
    8. 21.7 Chemistry of Amides
    9. 21.8 Chemistry of Thioesters and Acyl Phosphates: Biological Carboxylic Acid Derivatives
    10. 21.9 Polyamides and Polyesters: Step-Growth Polymers
    11. 21.10 Spectroscopy of Carboxylic Acid Derivatives
    12. Chemistry Matters—β-Lactam Antibiotics
    13. Key Terms
    14. Summary
    15. Summary of Reactions
    16. Additional Problems
  23. 22 Carbonyl Alpha-Substitution Reactions
    1. Why This Chapter?
    2. 22.1 Keto–Enol Tautomerism
    3. 22.2 Reactivity of Enols: α-Substitution Reactions
    4. 22.3 Alpha Halogenation of Aldehydes and Ketones
    5. 22.4 Alpha Bromination of Carboxylic Acids
    6. 22.5 Acidity of Alpha Hydrogen Atoms: Enolate Ion Formation
    7. 22.6 Reactivity of Enolate Ions
    8. 22.7 Alkylation of Enolate Ions
    9. Chemistry Matters—Barbiturates
    10. Key Terms
    11. Summary
    12. Summary of Reactions
    13. Additional Problems
  24. 23 Carbonyl Condensation Reactions
    1. Why This Chapter?
    2. 23.1 Carbonyl Condensations: The Aldol Reaction
    3. 23.2 Carbonyl Condensations versus Alpha Substitutions
    4. 23.3 Dehydration of Aldol Products: Synthesis of Enones
    5. 23.4 Using Aldol Reactions in Synthesis
    6. 23.5 Mixed Aldol Reactions
    7. 23.6 Intramolecular Aldol Reactions
    8. 23.7 The Claisen Condensation Reaction
    9. 23.8 Mixed Claisen Condensations
    10. 23.9 Intramolecular Claisen Condensations: The Dieckmann Cyclization
    11. 23.10 Conjugate Carbonyl Additions: The Michael Reaction
    12. 23.11 Carbonyl Condensations with Enamines: The Stork Enamine Reaction
    13. 23.12 The Robinson Annulation Reaction
    14. 23.13 Some Biological Carbonyl Condensation Reactions
    15. Chemistry Matters—A Prologue to Metabolism
    16. Key Terms
    17. Summary
    18. Summary of Reactions
    19. Additional Problems
  25. 24 Amines and Heterocycles
    1. Why This Chapter?
    2. 24.1 Naming Amines
    3. 24.2 Structure and Properties of Amines
    4. 24.3 Basicity of Amines
    5. 24.4 Basicity of Arylamines
    6. 24.5 Biological Amines and the Henderson–Hasselbalch Equation
    7. 24.6 Synthesis of Amines
    8. 24.7 Reactions of Amines
    9. 24.8 Reactions of Arylamines
    10. 24.9 Heterocyclic Amines
    11. 24.10 Spectroscopy of Amines
    12. Chemistry Matters—Green Chemistry II: Ionic Liquids
    13. Key Terms
    14. Summary
    15. Summary of Reactions
    16. Additional Problems
  26. 25 Biomolecules: Carbohydrates
    1. Why This Chapter?
    2. 25.1 Classification of Carbohydrates
    3. 25.2 Representing Carbohydrate Stereochemistry: Fischer Projections
    4. 25.3 D,L Sugars
    5. 25.4 Configurations of the Aldoses
    6. 25.5 Cyclic Structures of Monosaccharides: Anomers
    7. 25.6 Reactions of Monosaccharides
    8. 25.7 The Eight Essential Monosaccharides
    9. 25.8 Disaccharides
    10. 25.9 Polysaccharides and Their Synthesis
    11. 25.10 Some Other Important Carbohydrates
    12. Chemistry Matters—Sweetness
    13. Key Terms
    14. Summary
    15. Summary of Reactions
    16. Additional Problems
  27. 26 Biomolecules: Amino Acids, Peptides, and Proteins
    1. Why This Chapter?
    2. 26.1 Structures of Amino Acids
    3. 26.2 Amino Acids and the Henderson–Hasselbalch Equation: Isoelectric Points
    4. 26.3 Synthesis of Amino Acids
    5. 26.4 Peptides and Proteins
    6. 26.5 Amino Acid Analysis of Peptides
    7. 26.6 Peptide Sequencing: The Edman Degradation
    8. 26.7 Peptide Synthesis
    9. 26.8 Automated Peptide Synthesis: The Merrifield Solid-Phase Method
    10. 26.9 Protein Structure
    11. 26.10 Enzymes and Coenzymes
    12. 26.11 How Do Enzymes Work? Citrate Synthase
    13. Chemistry Matters—The Protein Data Bank
    14. Key Terms
    15. Summary
    16. Summary of Reactions
    17. Additional Problems
  28. 27 Biomolecules: Lipids
    1. Why This Chapter?
    2. 27.1 Waxes, Fats, and Oils
    3. 27.2 Soap
    4. 27.3 Phospholipids
    5. 27.4 Prostaglandins and Other Eicosanoids
    6. 27.5 Terpenoids
    7. 27.6 Steroids
    8. 27.7 Biosynthesis of Steroids
    9. Chemistry Matters—Saturated Fats, Cholesterol, and Heart Disease
    10. Key Terms
    11. Summary
    12. Additional Problems
  29. 28 Biomolecules: Nucleic Acids
    1. Why This Chapter?
    2. 28.1 Nucleotides and Nucleic Acids
    3. 28.2 Base Pairing in DNA
    4. 28.3 Replication of DNA
    5. 28.4 Transcription of DNA
    6. 28.5 Translation of RNA: Protein Biosynthesis
    7. 28.6 DNA Sequencing
    8. 28.7 DNA Synthesis
    9. 28.8 The Polymerase Chain Reaction
    10. Chemistry Matters—DNA Fingerprinting
    11. Key Terms
    12. Summary
    13. Additional Problems
  30. 29 The Organic Chemistry of Metabolic Pathways
    1. Why This Chapter?
    2. 29.1 An Overview of Metabolism and Biochemical Energy
    3. 29.2 Catabolism of Triacylglycerols: The Fate of Glycerol
    4. 29.3 Catabolism of Triacylglycerols: β-Oxidation
    5. 29.4 Biosynthesis of Fatty Acids
    6. 29.5 Catabolism of Carbohydrates: Glycolysis
    7. 29.6 Conversion of Pyruvate to Acetyl CoA
    8. 29.7 The Citric Acid Cycle
    9. 29.8 Carbohydrate Biosynthesis: Gluconeogenesis
    10. 29.9 Catabolism of Proteins: Deamination
    11. 29.10 Some Conclusions about Biological Chemistry
    12. Chemistry Matters—Statin Drugs
    13. Key Terms
    14. Summary
    15. Additional Problems
  31. 30 Orbitals and Organic Chemistry: Pericyclic Reactions
    1. Why This Chapter?
    2. 30.1 Molecular Orbitals of Conjugated Pi Systems
    3. 30.2 Electrocyclic Reactions
    4. 30.3 Stereochemistry of Thermal Electrocyclic Reactions
    5. 30.4 Photochemical Electrocyclic Reactions
    6. 30.5 Cycloaddition Reactions
    7. 30.6 Stereochemistry of Cycloadditions
    8. 30.7 Sigmatropic Rearrangements
    9. 30.8 Some Examples of Sigmatropic Rearrangements
    10. 30.9 A Summary of Rules for Pericyclic Reactions
    11. Chemistry Matters—Vitamin D, the Sunshine Vitamin
    12. Key Terms
    13. Summary
    14. Additional Problems
  32. 31 Synthetic Polymers
    1. Why This Chapter?
    2. 31.1 Chain-Growth Polymers
    3. 31.2 Stereochemistry of Polymerization: Ziegler–Natta Catalysts
    4. 31.3 Copolymers
    5. 31.4 Step-Growth Polymers
    6. 31.5 Olefin Metathesis Polymerization
    7. 31.6 Intramolecular Olefin Metathesis
    8. 31.7 Polymer Structure and Physical Properties
    9. Chemistry Matters—Degradable Polymers
    10. Key Terms
    11. Summary
    12. Additional Problems
  33. A | Nomenclature of Polyfunctional Organic Compounds
  34. B | Acidity Constants for Some Organic Compounds
  35. C | Glossary
  36. D | Periodic Table
  37. Answer Key
    1. Chapter 1
    2. Chapter 2
    3. Chapter 3
    4. Chapter 4
    5. Chapter 5
    6. Chapter 6
    7. Chapter 7
    8. Chapter 8
    9. Chapter 9
    10. Chapter 10
    11. Chapter 11
    12. Chapter 12
    13. Chapter 13
    14. Chapter 14
    15. Chapter 15
    16. Chapter 16
    17. Chapter 17
    18. Chapter 18
    19. Chapter 19
    20. Chapter 20
    21. Chapter 21
    22. Chapter 22
    23. Chapter 23
    24. Chapter 24
    25. Chapter 25
    26. Chapter 26
    27. Chapter 27
    28. Chapter 28
    29. Chapter 29
    30. Chapter 30
    31. Chapter 31
  38. Index

19 • Additional Problems

19 • Additional Problems

Visualizing Chemistry

Problem 19-27
Each of the following substances can be prepared by a nucleophilic addition reaction between an aldehyde or ketone and a nucleophile. Identify the reactants from which each was prepared. If the substance is an acetal, identify the carbonyl compound and the alcohol; if it is an imine, identify the carbonyl compound and the amine; and so forth.
(a)
A ball-and-stick model of a six-membered ring with two oxygen members, spaced with one carbon between them. That carbon has a methyl substituent.
(b)
A ball-and-stick model shows benzene ring linked to methylene group. This is linked to a nitrogen atom double bonded to carbon. This is linked to two methyl groups.
(c)
A ball-and-stick model of a cyclopentene linked to a cyclopentane with nitrogen atom.
(d)
A ball-and-stick model shows a benzene ring with a methyl group, C H linked to a hydroxyl. C H is also linked to two methyl groups.
Problem 19-28

The following molecular model represents a tetrahedral intermediate resulting from addition of a nucleophile to an aldehyde or ketone. Identify the reactants, and write the structure of the final product when the nucleophilic addition reaction is complete.

The ball-and-stick model shows a cyclopentane ring with nitrogen atom attached to three-carbon chain with hydroxyl and methyl group on the first carbon, and methyl group on the second carbon.
Problem 19-29
The enamine prepared from acetone and dimethylamine is shown in its lowest-energy form.
(a)
What is the geometry and hybridization of the nitrogen atom?
(b)
What orbital on nitrogen holds the lone pair of electrons?
(c)

What is the geometric relationship between the p orbitals of the double bond and the nitrogen orbital that holds the lone pair? Why do you think this geometry represents the minimum energy?

The ball-and-stick model shows a three-carbon chain with a double bond between first and second carbons. The second carbon is attached to N, N-dimethyl amine group

Mechanism Problems

Problem 19-30
Predict the product(s) and propose a mechanism for each of the following reactions:
(a)
The reaction shows 3-phenylpropanoyl chloride with aluminum chloride to produce an unknown product depicted by a question mark.
(b)
The reaction shows methoxybenzene with acetyl chloride in the presence of aluminum chloride to yield an unknown product denoted by a question mark.
Problem 19-31
Predict the product(s) and propose a mechanism for each of the following reactions:
(a)
The reaction shows butan-2-one with ethylene glycol using a hydrogen ion catalyst, producing an unknown product marked with a question mark.
(b)
The reaction shows acetone with (1S,2S)-cyclohexane-1, 2-diol using a hydrogen ion catalyst, yielding an unknown product marked with a question mark.
Problem 19-32
Predict the product(s) and propose a mechanism for each of the following reactions:
(a)
The reaction shows fused cyclohexane and cyclopentane rings with oxygen and methyl groups with hydrogen ion catalyst and water to yield an unknown product denoted by a question mark.
(b)
The reaction shows a compound with benzene attached to cyclopentane with oxygen, hydrogen, and methyl groups with hydrogen ion catalyst and water, yielding unknown product marked with a question mark.
Problem 19-33
Predict the product(s) and propose a mechanism for each of the following reactions:
(a)
The reaction shows pentan-3-one with hydroxylamine to yield an unknown product marked with a question mark.
(b)
The reaction shows acetophenone with dimethylamine resulting in an unknown product represented by a question mark.
Problem 19-34
Predict the product(s) and propose mechanisms for the following reactions:
(a)
The reaction shows N-(butan-2-ylidine)methanamine with hydrochloric acid and water to yield an unknown product marked with a question mark.
(b)
The reaction shows N, N-dimethylcyclohex-1-enamine with hydrochloric acid and water to yield an unknown product marked with a question mark.
Problem 19-35
The following reaction begins with an acetal and converts it into a different acetal. Predict the product(s) and propose a mechanism.
(a)
The reaction shows 1,2-dihydroxybenzene and 2, 2-dimethoxypropane in the presence of hydrogen ion to yield the unknown product marked with a question mark.
(b)
The reaction shows 3, 3-dimethoxypentane with ethylene glycol in the presence of hydrogen ions, producing an unknown product denoted by a question mark.
Problem 19-36

When α-glucose is treated with an acid catalyst in the presence of an alcohol, an acetal is formed. Propose a mechanism for this process and give the structure of the stereoisomeric acetal that you would also expect as a product.

The reaction shows the conversion of alpha-glucose to acetal in the presence of hydrogen ions and methanol.
Problem 19-37
Predict the products of the following Wolff–Kishner reactions. Write the mechanism for each, beginning from the hydrazone intermediate.
(a)
Cyclohexanone with benzene fused to C 2 and C 3 reacts with hydrazine and potassium hydroxide to generate an unidentified product, indicated by a question mark.
(b)
Bicyclo[2.2.1]heptane with an oxo group on C 2 reacts with hydrazine and potassium hydroxide to generate an unidentified product, indicated by a question mark.
Problem 19-38

Aldehydes can be prepared by the Wittig reaction using (methoxymethylene)triphenylphosphorane as the Wittig reagent and then hydrolyzing the product with acid. For example,

A cyclohexanone reacts with (methoxymethylene)-triphenylphosphorane to form an intermediate, that reacts with a hydronium ion, yielding a final product, cyclohexanecarbaldehyde.
(a)
How would you prepare the necessary phosphorane?
(b)
Propose a mechanism for the hydrolysis step.
Problem 19-39

One of the steps in the metabolism of fats is the reaction of an unsaturated acyl CoA with water to give a β-hydroxyacyl CoA. Propose a mechanism.

The reaction of unsaturated acyl coenzyme A with water to yield beta-hydroxyacyl coenzyme A, where a hydroxyl group is attached to the beta-carbon of the chain.
Problem 19-40

Aldehydes and ketones react with thiols to yield thioacetals just as they react with alcohols to yield acetals. Predict the product of the following reaction, and propose a mechanism:

The reaction shows a cyclopentanone with two molecules of ethanethiol, in the presence of a proton catalyst to yield an unknown compound indicated by a question mark.
Problem 19-41

Ketones react with dimethylsulfonium methylide to yield epoxides. Suggest a mechanism for the reaction.

The reaction shows cyclohexanone with dimethylsulfonium methylide in D M S O to yield an epoxide, where an oxirane carbon is attached to a cyclohexane ring and dimethylsulfide.
Problem 19-42

Propose a mechanism for the following reaction.

The reaction shows a ketone converted to an acid with sodium hydroxide (first reaction), followed by hydrochloric acid in water (second reaction).
Problem 19-43

Paraldehyde, a sedative and hypnotic agent, is prepared by treatment of acetaldehyde with an acidic catalyst. Propose a mechanism for the reaction.

Three acetaldehyde molecules react with proton catalyst giving paraldehyde, where three carbon atoms of cyclohexane ring are replaced with oxygen. Three methyl groups are connected to carbon atoms in ring.
Problem 19-44

The Meerwein–Ponndorf–Verley reaction involves reduction of a ketone by treatment with an excess of aluminum triisopropoxide, [(CH3)2CHO]3Al. The mechanism of the process is closely related to the Cannizzaro reaction in that a hydride ion acts as a leaving group. Propose a mechanism.

The reaction shows cyclohexanone with aluminum triisopropoxide, then hydronium ion to yield two products: cyclohexanol and acetone (three-carbon).
Problem 19-45

Propose a mechanism to account for the formation of 3,5-dimethylpyrazole from hydrazine and 2,4-pentanedione. What has happened to each carbonyl carbon in going from starting material to product.

The reaction shows 2,4-pentanedione with hydrazine and a proton to form 3,5-dimethylpyrazole.
Problem 19-46

In light of your answer to Problem 19-45, propose a mechanism for the formation of 3,5-dimethylisoxazole from hydroxylamine and 2,4-pentanedione.

The structure of 3,5-dimethylisoxazole shows a cyclopentadiene ring with adjacent oxygen and nitrogen atoms. A methyl group is attached to the carbons adjacent to oxygen and nitrogen.
Problem 19-47

Trans alkenes are converted into their cis isomers and vice versa on epoxidation followed by treatment of the epoxide with triphenylphosphine. Propose a mechanism for the reaction.

Trans alkene reacts with R C O 3 H to form trans epoxide, which reacts with P Ph 3 to form cis alkene and Ph 3 P double bond O.
Problem 19-48

Treatment of an α,β-unsaturated ketone with basic aqueous hydrogen peroxide yields an epoxy ketone. The reaction is specific to unsaturated ketones; isolated alkene double bonds do not react. Propose a mechanism.

The reaction shows 2-cyclohexenone with hydrogen peroxide, sodium hydroxide, and water to yield an epoxy ketone, where the cyclohexanone ring is fused with oxirane at the second and third carbons.
Problem 19-49

One of the biological pathways by which an amine is converted to a ketone involves two steps: (1) oxidation of the amine by NAD+ to give an imine and (2) hydrolysis of the imine to give a ketone plus ammonia. Glutamate, for instance, is converted by this process into α-ketoglutarate. Show the structure of the imine intermediate, and propose mechanisms for both steps.

The reaction shows the conversion of glutamate with N A D plus to form an imine, which yields alpha-ketoglutarate and ammonia on reaction with water.
Problem 19-50

Primary amines react with esters to yield amides: RCO2R′ + R″NH2 → RCONHR″ + R′OH. Propose a mechanism for the following reaction of an α,β-unsaturated ester.

The reaction shows an ester with methylamine to form amide and methanol. The amide structure shows a cyclopentanone ring with nitrogen adjacent to the carbonyl, bearing a methyl group.
Problem 19-51

When crystals of pure α-glucose are dissolved in water, isomerization occurs slowly to produce β-glucose. Propose a mechanism for the isomerization.

The reaction shows the interconversion of alpha-glucose and beta-glucose through a reversible reaction. The position of the hemiacetal hydroxyl group is axial in alpha and equatorial in beta.
Problem 19-52

The Wharton reaction converts an epoxy ketone to an allylic alcohol by reaction with hydrazine. Review the Wolff–Kishner reaction in Section 19.9 and then propose a mechanism.

Wharton reaction shows the conversion of an epoxy ketone to an allylic alcohol and N 2, by reacting with hydrazine using a catalyst containing sodium acetate, and acetic acid.

Naming Aldehydes and Ketones

Problem 19-53
Draw structures corresponding to the following names:
(a)
Bromoacetone
(b)
(S)-2-Hydroxypropanal
(c)
2-Methyl-3-heptanone
(d)
(2S,3R)-2,3,4-Trihydroxybutanal
(e)
2,2,4,4-Tetramethyl-3-pentanone
(f)
4-Methyl-3-penten-2-one
(g)
Butanedial
(h)
3-Phenyl-2-propenal
(i)
6,6-Dimethyl-2,4-cyclohexadienone
(j)
p-Nitroacetophenone
Problem 19-54
Draw and name the seven aldehydes and ketones with the formula C5H10O. Which are chiral?
Problem 19-55
Give IUPAC names for the following compounds:
(a)
The structure shows cyclohexene ring with a carbonyl on the first carbon. A double bond is shared between the third and fourth carbons with a methyl group on the third.
(b)
The structure shows a central carbon bonded with hydrogen (wedge-bonded), a hydroxyl group (wedge-bonded), a hydroxymethyl group (dashed-bonded), and C H O group (dashed-bonded).
(c)
The structure shows cyclohexanone ring with a methyl group at the second carbon, a tert-butyl group at the fifth carbon, and a double bond between second and third.
(d)
The structure shows a five-carbon chain with, couting from the left, a methyl group on the second and a carbonyl on the third carbon.
(e)
The structure shows a four-carbon chain with, counting from the left, a hydroxyl group on the second carbon, and the fourth carbon part of a C H O group.
(f)
The structure shows a benzene ring with two C H O groups on the first and fourth carbon atoms.
Problem 19-56
Draw structures of compounds that fit the following descriptions:
(a)
An α,β-unsaturated ketone, C6H8O
(b)
An α-diketone
(c)
An aromatic ketone, C9H10O
(d)
A diene aldehyde, C7H8O

Reactions of Aldehydes and Ketones

Problem 19-57
Predict the products of the reaction of (1) phenylacetaldehyde and (2) acetophenone with the following reagents:
(a)
NaBH4, then H3O+
(b)
Dess–Martin reagent
(c)
NH2OH, HCl catalyst
(d)
CH3MgBr, then H3O+
(e)
2 CH3OH, HCl catalyst
(f)
H2NNH2, KOH
(g)
(C6H5)3P = CH2
(h)
HCN, KCN
Problem 19-58
Show how you might use a Wittig reaction to prepare the following alkenes. Identify the alkyl halide and the carbonyl components.
(a)
The structure of (1E,3E)-1,4-diphenylbuta-1,3-diene.
(b)
A central carbon with phenyl substituent and a double bond to C 1 of a cyclohexane ring.
Problem 19-59
How would you use a Grignard reaction on an aldehyde or ketone to synthesize the following compounds?
(a)
2-Pentanol
(b)
1-Butanol
(c)
1-Phenylcyclohexanol
(d)
Diphenylmethanol
Problem 19-60
How might you carry out the following selective transformations? One of the two schemes requires a protection step. (Recall from Section 19.4 that aldehydes are more reactive than ketones toward nucleophilic addition.)
(a)
The reaction shows the conversion of 5-oxohexanal to 6-hydroxyhexan-2-one.
(b)
The reaction shows the conversion of 5-oxohexanal to 5-hydroxyhexanal.
Problem 19-61
How would you prepare the following substances from 2-cyclohexenone? More than one step may be needed.
(a)
The structure of cyclohexene.
(b)
The structure of 3-phenylcyclohexanone shows a phenyl group attached to the third carbon of the cyclohexanone ring.
(c)
The structure of 3-oxocyclohexanecarboxylic acid shows a carboxylic acid group attached to the C 1 of a cyclohexane with an oxo group at C 3.
(d)
The structure of methylcyclohexane shows a methyl group attached to a cyclohexane ring.
Problem 19-62
How would you synthesize the following substances from benzaldehyde and any other reagents needed?
(a)
The structure of 2-phenylacetaldehyde shows a benzene ring with a C H 2 C H O group as a side chain.
(b)
The structure shows a pyrrolidine ring attached through the nitrogen atom to a styrene.
(c)
A central carbon with phenyl substituent and a double bond to C 1 of a cyclopentane ring.
Problem 19-63

Carvone is the major constituent of spearmint oil. What products would you expect from reaction of carvone with the following reagents?

The carvone structure shows a cyclohexanone ring with a methyl group at the second carbon and an isopropyl on the fifth. A double bond connects the second and third carbon.
(a)
(CH3)2CuLi+, then H3O+
(b)
LiAlH4, then H3O+
(c)
CH3NH2
(d)
C6H5MgBr, then H3O+
(e)
H2/Pd
(f)
HOCH2CH2OH, HCl
(g)
(C6H5)3 P + C HCH3
Problem 19-64
How would you synthesize the following compounds from cyclohexanone?
(a)
1-Methylcyclohexene
(b)
2-Phenylcyclohexanone
(c)
cis-1,2-Cyclohexanediol
(d)
1-Cyclohexylcyclohexanol

Spectroscopy

Problem 19-65
At what position would you expect to observe IR absorptions for the following molecules?
(a)
The structure of 4-androstene-3, 17-dione shows three fused cyclohexane rings and one cyclopentane ring with two methyl groups at junctions. Two ketone groups are located on third and seventeenth carbon.
(b)
The structure of 1-indanone shows a benzene ring fused to C 2 and C 3 of a cyclopentanone ring.
(c)
The structure of 1-indanone shows a benzene ring fused to C 3 and C 4 of a cyclopentanone ring.
(d)
The structure shows a benzaldehyde with a side chain C H 2 C O C H 3 group at the para position of the ring.
Problem 19-66
Acid-catalyzed dehydration of 3-hydroxy-3-phenylcyclohexanone leads to an unsaturated ketone. What possible structures are there for the product? At what position in the IR spectrum would you expect each to absorb? If the actual product has an absorption at 1670 cm–1, what is its structure?
Problem 19-67

Choose the structure that best fits the IR spectrum shown.

The infrared spectrum of an unknown compound shows peaks at specific wavenumbers, including strong peaks at around 3100, 1727, and 1000 centimeters inverse.
(a)
The structure of trans-undec-2-enal shows an eleven-carbon chain with a trans double bond between the second and third carbon and an aldehyde at C 1.
(b)
The structure of undec-10-enal shows an eleven-carbon chain with a double between the tenth and eleventh carbon and an aldehyde at C 1.
(c)
The structure of cis-undec-2-enal shows an eleven-carbon chain with a cis double bond between the second and third carbon and an aldehyde at C 1.
(d)
The structure of 9-methyldec-8-enal shows a ten-carbon chain with a double bond between the eighth and ninth carbons, a methyl at the ninth carbon, and an aldehyde at C 1.
Problem 19-68
Propose structures for molecules that meet the following descriptions. Assume that the kinds of carbons (1°, 2°, 3°, or 4°) have been assigned by DEPT–NMR.
(a)
C6H12O; IR: 1715 cm–1; 13C NMR: 8.0 δ (1°), 18.5 δ (1°), 33.5 δ (2°), 40.6 δ (3°), 214.0 δ (4°)
(b)
C5H10O; IR: 1730 cm–1; 13C NMR: 22.6 δ (1°), 23.6 δ (3°), 52.8 δ (2°), 202.4 δ (3°)
(c)
C6H8O; IR: 1680 cm–1; 13C NMR: 22.9 δ (2°), 25.8 δ (2°), 38.2 δ (2°), 129.8 δ (3°), 150.6 δ (3°), 198.7 δ (4°)
Problem 19-69

Compound A, C8H10O2, has an intense IR absorption at 1750 cm–1 and gives the 13C NMR spectrum shown. Propose a structure for A.

The C-13 spectrum shows peaks at shifts of 0 (T M S), 38, 42, and 219, measured in parts per million.
Problem 19-70
Propose structures for ketones or aldehydes that have the following 1H NMR spectra:
(a)

C4H7ClO

IR: 1715 cm–1

The proton spectrum show peaks at shifts at 0 (T M S) 1.62 (doublet), 2.33 (singlet), and 4.32 (quartet) with relative areas 3.00, 3.00, and 1.00 respectively.
(b)

C7H14O

IR: 1710 cm–1

The proton spectrum show peaks at shifts of 0 (T M S), 1.02, 2.12, and 2.33 (all singlets) with relative areas 4.50, 1.50, and 1.00 respectively.

General Problems

Problem 19-71

When 4-hydroxybutanal is treated with methanol in the presence of an acid catalyst, 2-methoxytetrahydrofuran is formed. Explain.

4-Hydroxybutanal reacts with methanol and hydrogen chloride to yield 2-methoxytetrahydrofuran. A methoxy group is attached to the C 2 position of tetrahydrofuran ring.
Problem 19-72
The SN2 reaction of (dibromomethyl)benzene, C6H5CHBr2, with NaOH yields benzaldehyde rather than (dihydroxymethyl)benzene, C6H5CH(OH)2. Explain.
Problem 19-73
Reaction of 2-butanone with HCN yields a chiral product. What stereochemistry does the product have? Is it optically active?
Problem 19-74

The amino acid methionine is biosynthesized by a multistep route that includes reaction of an imine of pyridoxal phosphate (PLP) to give an unsaturated imine, which then reacts with cysteine. What kinds of reactions are occurring in the two steps?

O-succinylhomoserine- P L P imine undergoes a reaction to form an unsaturated imine which further reacts with cysteine to form the final product.
Problem 19-75
Each of the following reaction schemes has one or more flaws. What is wrong in each case? How would you correct each scheme?
(a)
3-oxo-bicyclo[4.4.0]dec-2-ene reacts with methylmagnesium bromide, then hydronium to form 1-methyl-3-oxobicylo[4.4.0]decane, which reacts with lithium aluminum hydride, then hydronium to form 1-methylbicyclo[4.4.0]decane.
(b)
3-phenylprop-2-en-1-ol reacts with chromium trioxide and hydronium ion to form 3-phenylprop-2-enal. This reacts with hydrogen ions and methanol to form 1,1-dimethoxy-3-phenylprop-2-ene.
(c)
Acetone reacts with hydrogen cyanide, potassium cyanide, and ethanol to form 2-cyanopropan-2-ol. This reacts with hydronium to form 1-amino-2-methylpropan-2-ol.
Problem 19-76

6-Methyl-5-hepten-2-one is a constituent of lemongrass oil. How could you synthesize this substance from methyl 4-oxopentanoate?

Structure of methyl 4-oxopentanoate, a five-carbon methyl ester with a ketone at C 4.
Problem 19-77

Tamoxifen is a drug used in the treatment of breast cancer. How would you prepare tamoxifen from benzene, the following ketone, and any other reagents needed?

Ketone transforms to tamoxifen, replacing the carbonyl oxygen of ketone with a carbon linked to ethyl and benzene in tamoxifen. The unknown reagent is depicted as a question mark.
Problem 19-78
Compound A, MW = 86, shows an IR absorption at 1730 cm–1 and a very simple 1H NMR spectrum with peaks at 9.7 δ (1 H, singlet) and 1.2 δ (9 H, singlet). Propose a structure for A.
Problem 19-79
Compound B is isomeric with A (Problem 19-78) and shows an IR peak at 1715 cm–1. The 1H NMR spectrum of B has peaks at 2.4 δ (1 H, septet, J = 7 Hz), 2.1 δ (3 H, singlet), and 1.2 δ (6 H, doublet, J = 7 Hz). What is the structure of B?
Problem 19-80

The 1H NMR spectrum shown is that of a compound with the formula C9H10O. How many double bonds and/or rings does this compound contain? If the unknown compound has an IR absorption at 1690 cm–1, what is a likely structure?

Proton spectrum shows shifts of 0 (T M S), 1.20 (triplet), 2.97 (quartet, 7.39 and 7.56 (multiplet), and 7.97 (doublet). Relative areas are 3.00, 2.00, 2.00, 1.00, and 2.00 respectively.
Problem 19-81

The 1H NMR spectrum shown is that of a compound isomeric with the one in Problem 19-80. This isomer has an IR absorption at 1730 cm–1. Propose a structure. [Note: Aldehyde protons (CHO) often show low coupling constants to adjacent hydrogens, so the splitting of aldehyde signals is not always apparent.]

Proton spectrum shows shifts of 0 (T M S), 2.75 (triplet), 2.95 (triplet), 7.23 and 7.31 (multiplet), and 9.82 (singlet). Relative areas are 2.00, 2.00, 3.00, 2.00, and 1.00 respectively.
Problem 19-82
Propose structures for ketones or aldehydes that have the following 1H NMR spectra:
(a)

C9H10O2: IR: 1695 cm–1

Proton spectrum shows shifts of 0 (T M S), 1.44 (triplet), 4.08 (quartet), 6.98 (doublet), 7.81 (doublet), and 9.87 (singlet). Relative areas are 3.00, 2.00, 2.00, 2.00, and 1.00 respectively.
(b)

C4H6O: IR: 1690 cm–1

Proton spectrum shows shifts of 0 (T M S), 1.86 (singlet), 6.00 (singlet), 6.31 (singlet), and 9.57 (singlet). Relative areas are 3.00, 1.00, 1.00, and 1.00 respectively.
Problem 19-83
Propose structures for ketones or aldehydes that have the following 1H NMR spectra.
(a)

C10H12O: IR: 1710 cm–1

Proton spectrum shows shifts of 0 (T M S), 1.01 (triplet), 2.47 (quartet), 3.66 (singlet), 7.28 (multiplet). Relative areas are 1.50, 1.00, 1.00, and 2.50 respectively.
(b)

C6H12O3: IR: 1715 cm–1

Proton spectrum shows shifts of 0 (T M S), 2.18 (singlet), 2.74 (doublet), 3.37 (singlet), and 4.79 (triplet). Relative areas are 3.00, 2.00, 6.00, and 1.00 respectively.
Problem 19-84

When glucose (Problem 19-51) is treated with NaBH4, reaction occurs to yield sorbitol, a polyalcohol commonly used as a food additive. Show how this reduction occurs.

Alpha-glucose reacts with sodium borohydride and water to produce sorbitol, a six-carbon chain with one hydroxyl group on each carbon.
Problem 19-85

The proton and carbon NMR spectra for each of three isomeric ketones with the formula C7H14O are shown. Assign a structure to each pair of spectra.

C-13 N M R spectrum displays peaks at 221.04, 44.79, 17.39, and 13.78, along with a C D C l 3 peak around 80. Proton spectrum with shifts around 0.95 (triplet), around 1.6 (sextet), and around 2.35 (triplet). Relative areas indicated with integral lines are 2.91, 2.00, and 1.96 respectively. Carbon spectrum B displays peaks: spiky line at 218.40, unevenly shaded peaks at 80 delta for C D C l 3, medium-length peak at 38.85, and tall peak at 18.55. Proton spectrum with shifts around 1.1 (doublet) and around 2.8 (septet). Relative areas indicated with integral lines are 6.18 and 1.04 respectively. Carbon spectrum C shows peaks at 218.31, 75 delta (C D C l 3), 55.98, set between 29 to 32.5 delta, and expanded view with peaks at 32.27, 30.88, 29.73. Proton spectrum with shifts around 1.0 (singlet), 2.15 (singlet), and 2.35 (singlet). Relative areas indicated with integral lines are 8.91, 2.98, and 1.95 respectively.
Problem 19-86

The proton NMR spectrum for a compound with formula C10H12O2 is shown below. The infrared spectrum has a strong band at 1711 cm–1. The broadband-decoupled 13C NMR spectral results are tabulated along with the DEPT-135 and DEPT-90 information. Draw the structure of this compound.

Proton spectrum with singlets at 2.1, 3.6, and 3.8, doublets at 6.8 and 7.1. Relative areas 3.01, 2.15, 3.13, 2.01, 1.91 respectively. Inset shows 13 C N M R results.
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