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문제 51
The 1H NMR chemical shifts of nitromethane, dinitromethane, and trinitromethane are at δ6.10, δ4.33, and δ7.52. Match each chemical shift with the compound. Explain how chemical shift correlates with pKa.
문제 52
Which of the following compounds decarboxylates when heated?
문제 53d
Draw the products of the following reactions:
d. diethyl 1,2-benzenedicarboxylate + sodium ethoxide: (1) slow addition of ethyl acetate; (2) HCl
문제 55a
Draw the products of the following reactions:
a.
문제 55b
Draw the products of the following reactions:
b.
문제 57
An aldol addition can be catalyzed by acids as well as by bases. Propose a mechanism for the acid-catalyzed aldol addition of propanal.
문제 58
In the presence of excess base and excess halogen, a methyl ketone is converted to a carboxylate ion. The reaction is known as the haloform reaction because one of the products is haloform (chloroform, bromoform, or iodoform). Before spectroscopy became a routine analytical tool, the haloform reaction served as a test for methyl ketones: the formation of iodoform, a bright yellow compound, signaled that a methyl ketone was present. Why do only methyl ketones form a haloform?
문제 59a,b,c
Identify A–C. (Hint: A shows three singlets in its 1H NMR spectrum with integral ratios 3 : 2 : 3 and gives a positive iodoform test; see Problem 58.)
문제 60a
Using cyclopentanone as the reactant, show the product of a. acid-catalyzed keto–enol interconversion.
문제 60a,b
Using cyclopentanone as the reactant, show the product of
b. an aldol addition.
c. an aldol condensation.
문제 61
Show how 4-methyl-3-hexanol can be synthesized from 3-pentanone.
문제 62
Show how the following compound can be synthesized from the given starting material. (Hint: Start with an acetoacetic ester.)
문제 64b
A β-ɣ-unsaturated carbonyl compound rearranges to a more stable conjugated ⍺,β-unsaturated compound in the presence of either acid or base. b. Propose a mechanism for the acid-catalyzed rearrangement.
문제 65a
There are other condensation reactions similar to the aldol and Claisen condensations:
a. The Perkin condensation is the condensation of an aromatic aldehyde and acetic anhydride. Draw the product obtained from the following Perkin condensation:
문제 65b
There are other condensation reactions similar to the aldol and Claisen condensations:
b. What compound is formed if water is added to the product of a Perkin condensation?
문제 65c
There are other condensation reactions similar to the aldol and Claisen condensations:
c. The Knoevenagel condensation is the condensation of an aldehyde or a ketone that has no a-hydrogens and a compound such as diethyl malonate that has an a-carbon flanked by two electron-withdrawing groups. Draw the product obtained from the following Knoevenagel condensation:
문제 65d
What product is obtained when the product of a Knoevenagel condensation is heated in an aqueous acidic solution?
문제 66b
Indicate how each of the following compounds can be synthesized from the given starting material and any other necessary reagents:
b.
문제 66c
Indicate how each of the following compounds can be synthesized from the given starting material and any other necessary reagents:
c.
문제 67a
The Reformatsky reaction is an addition reaction in which an organozinc reagent is used instead of a Grignard reagent to add to the carbonyl group of an aldehyde or a ketone. Because the organozinc reagent is less reactive than a Grignard reagent, a nucleophilic addition to the ester group does not occur. The organozinc reagent is prepared by treating an α-bromo ester with zinc.
Describe how each of the following compounds can be prepared, using a Reformatsky reaction:
a.
문제 67c
The Reformatsky reaction is an addition reaction in which an organozinc reagent is used instead of a Grignard reagent to add to the carbonyl group of an aldehyde or a ketone. Because the organozinc reagent is less reactive than a Grignard reagent, a nucleophilic addition to the ester group does not occur.
The organozinc reagent is prepared by treating an α-bromo ester with zinc.
Describe how each of the following compounds can be prepared, using a Reformatsky reaction:
c.
문제 68
The ketone whose 1H NMR spectrum is shown here was obtained as the product of an acetoacetic ester synthesis. What alkyl halide was used in the synthesis?
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문제 69d
Indicate how the following compounds can be synthesized from cyclohexanone and any other necessary reagents:
d.
문제 70
Compound A with molecular formula C6H10 has two peaks in its 1H NMR spectrum, both of which are singlets (with ratio 9 : 1). Compound A reacts with an acidic aqueous solution containing mercuric sulfate to form compound B, which gives a positive iodoform test (Problem 58) and has an 1H NMR spectrum that shows two singlets (with ratio 3 : 1). Identify A and B.
문제 71b
b. What carboxylic acid is formed when the malonic ester synthesis is carried out with two equivalents of malonic ester, one equivalent of 1,5-dibromopentane, and two equivalents of base?
문제 72a
Draw the products of the following reactions:
a.
문제 72b
Draw the products of the following reactions:
b.
문제 72c
Draw the products of the following reactions:
c.
문제 72d
Draw the products of the following reactions:
d.
문제 73
Show how the following compound can be prepared from starting materials that have no more than five carbons:
