Chapter 21, Problem 123CP

Identify products A and B from the given 1H NMR data. Treatment of acetone [(CH3)2C=O] with dilute aqueous base forms B. Compound B exhibits four singlets in its 1H NMR spectrum at 1.3 (6 H), 2.2 (3 H), 2.5 (2 H), and 3.8 (1H) ppm. What is the structure of B?

A key step in the synthesis of a natural product is shown below. Answer sections (iv) and (v) related to this reaction. OH R CO₂Me S ان - شبه P CO₂Me Heat H H CO₂Me (iv) Give a curly arrow reaction mechanism for the formation of compound Q and suggest why the formation of the given diastereomer is favoured. (v) Compound P can be formed from S and R. Suggest the identity of S and state what type of reaction can be used form P.

Compound A is difficult to prepare owing to its readily base-catalyzed isomerization to compound B. Propose a reasonable mechanism for this isomerization.

Mustard gas, Cl¬CH2CH2¬S¬CH2CH2¬Cl, was used as a poisonous chemical agentin World War I. Mustard gas is much more toxic than a typical primary alkyl chloride. Itstoxicity stems from its ability to alkylate amino groups on important metabolic enzymes,rendering the enzymes inactive.(a) Propose a mechanism to explain why mustard gas is an exceptionally potent alkylatingagent

During a recent synthesis of hispidospermidin, a fungal isolate and an inhibitor of phospholipase C, the investigators employed employed a novel Friedel-Crafts acylation on a nonaromatic system (J. Am. Chem. Soc. 1998, 120, 4039-4040). The following acid chloride was treated with a Lewis acid, affording a mixture of two products, 1 and 2. Propose a plausible mechanism for the formation of compounds 1 and 2. CI AICI 进一步农 COCI 2 Part 1 Incorrect. Which of the four mechanistic steps is happening? Add curved arrow(s) to draw the first step of the mechanism. Modify the given drawing of the products as needed to show the intermediate that is formed in this step. Use the +/- tools to add/remove charges. CH₂ H St Edit Drawing H₂C H CH₂ CI Q M ΟΣ

Propose a detailed mechanism for the transformations presented. represent the Intermediate structure A.

In an aqueous solution containing sodium bicarbonate, aniline reacts quickly withbromine to give 2,4,6-tribromoaniline. Nitration of aniline requires very strong conditions,however, and the yields (mostly m-nitroaniline) are poor.(a) What conditions are used for nitration, and what form of aniline is present under theseconditions?

Reaction of aldehyde D with amino alcohol E in the presence of NaH forms F (molecular formula C11H15NO2). F absorbs at 1730 cm−1 in its IR spectrum. F also shows eight lines in its 13C NMR spectrum, and gives the following 1H NMR spectrum: 2.32 (singlet, 6 H), 3.05 (triplet, 2 H), 4.20 (triplet, 2 H), 6.97 (doublet, 2 H), 7.82 (doublet, 2 H), and 9.97 (singlet, 1 H) ppm. Propose a structure for F. We will learn about this reaction in Chapter 18.

A step in a synthesis of PGE1 (prostanglandin E1, alprostadil) is reaction of a trisubstituted cyclohexene with bromine to form a bromolactone. Alprostadil is used as temporary therapy for infants born with congenital heart defects that restrict pulmonary blood flow. It brings about dilation of the ductus arteriosus, which in turn increases blood flow in the lungs and blood oxygenation. Propose a mechanism for formation of This bromolactone, and account for the observed stereochemistry of each substituent on the cyclohexane ring.