1. Figure Number: 19-00CO
Title: Acetyl-CoA
Caption: Space-filling model of acetyl-Coenzyme A.
Notes: Acetyl-CoA is used by the body in the citric acid cycle to increase the size of a 4-carbon intermediate (oxaloacetate) by two carbons, forming a 6-carbon intermediate (citrate). The body attaches the acetyl group (left end of figure) to oxaloacetate by removing a hydrogen from the methyl group of the acetyl and making the attachment to acetyl's alpha carbon, rather than attaching acetyl by its carbonyl carbon. This is possible because hydrogens attached to alpha carbons of carbonyl compounds are acidic and easily removable.

2. Figure Number: UN
Title: 2,4-Pentanedione
Caption: Electrostatic potential map of 2,4-pentanedione.
Notes: The enol tautomer of 2,4-pentanedione is more stable than the keto tautomer. The enol hydrogen in the enol tautomer is hydrogen bonded to the carbonyl oxygen of the carbonyl group beta to the enol group, forming a six-membered ring.

3. Figure Number: P52
Title: End-of-Chapter Problem 53
Caption: Proton NMR spectrum associated with end-of-chapter Problem 53.
Notes: The proton NMR spectrum in the figure was generated by a ketone produced by an acetoacetic ester synthesis. Ethyl acetoacetate was treated with base, followed by an alkyl bromide, followed by an acidic workup to yield the ketone generating the NMR. Determine the identity of the alkyl bromide used in the synthesis.

4. Figure Number: P65
Title: End-of-Chapter Problem 65
Caption: Proton NMR spectrum associated with end-of-chapter Problem 65.
Notes: Two carbonyl compounds were treated with base, forming an aldol intermediate which was dehydrated with heat and acid, produing an a,b-unsaturated ketone product that was used to generate the proton NMR spectrum shown in the figure. This final product has the molecular formula C10H10O. Determine the identities of the carbonyl compounds used in the aldol reaction.

5. Figure Number: 19-TB01
Title: Table The pKa Values of Some Carbon Acids
Caption:
Notes: