Draw the major product formed for each reaction. 100 (a) The conjugate acid of triethylamine has a pKa -11, the pKa of the most acidic sites of the substrate is ~20. (b) (c) (d) H3C N CH3 CH3 U-3.H H3C. then CH3l H3C Cu-Li H3C CH3 then H3C OCH3 que travoval nobmotancy cat to) LDA CH3 H3C O then CH3 H3C H CH3 H3C CH3 KOtBu 0 နန်းဝ Si S=0 | 11

PQ-22. Which structure is a reasonable intermediate in the acid-catalyzed hydrolysis of ethyl acetate, shown, in dilute aqueous acid? O O (A) H3C-C-OCH₂CH3 OH OH₂ (C) H3C-C-OCH₂CH3 H OH (B) H3C-C-OCH₂CH3 OH2 O (D) H3C-C

Most carboxylic acids have pKa's around 4-5. Keeping in mind what makes and carboxylic acid acidic, which of the following compounds would also have a pKa of ~5? (A) OH (B) OH OH (C) (D) OH

Asteltoxin, isolated from cultures of Aspergillus stellatus, exhibits a potent inhibitor on E. coli BF1 ATPase activity. During S. L. Schreiber's synthesis of asteltoxin, substance 1 was treated with a strong base to form anion 2. necessary representations. b) Determine whether each of the following bases would be suitable for deprotonation of substance 1 and explain your decision in each case: (i) NaOH, (ii) NaNH2, or (iii) CH3CO2Na.

As far back as the 16th century, South American Incas chewed the leaves of the coca bush, Erythroxylon coca, to combat fatigue. Chemical studies of Erythroxylon coca by Friedrich Wöhler in 1862 resulted in the discovery of cocaine, C17H21NO4, as the active component. Basic hydrolysis of cocaine leads to methanol, benzoic acid, and another compound called ecgonine, C9H15NO3. Oxidation of ecgonine with CrO3 yields a keto acid that readily loses CO2 on heating, giving tropinone. (a) What is a likely structure for the keto acid? (b) What is a likely structure for ecgonine, neglecting stereochemistry? (c) What is a likely structure for cocaine, neglecting stereochemistry?

Thioglycolic acid, HSCH2CO2H, a substance used in depilatory agents (hair removers) has pKa = 3.42. What is the percent dissociation of thioglycolic acid in a buffer solution at pH = 3.0?

Naturally occurring compounds called cyanogenic glycosides, such as lotaustralin, release hydrogen cyanide, HCN, when treated with aqueous acid. The reaction occurs by hydrolysis of the acetal linkage to form a cyanohydrin, which then expels HCN and gives a carbonyl compound. (a) Show the mechanism of the acetal hydrolysis and the structure of the cyanohydrin that results. (b) Propose a mechanism for the loss of HCN, and show the structure of the carbonyl compound that forms.

Electrostatic potential maps of anisole and thioanisole are shown. Which do you think is the stronger acid, p-methoxybenzoic acid or p-(methylthio)benzoic acid? Explain.

Rank the following compounds in order of increasing basicity and explain the order you chose.

(−)-Hyoscyamine, an optically active drug used to treat gastrointestinal disorders, is isolated from Atropa belladonna, the deadly nightshade plant, by a basic aqueous extraction procedure. If too much base is used during isolation, optically inactive material is isolated. (a) Explain this result by drawing a stepwise mechanism. (b) Explain why littorine, an isomer isolated from the tailflower plant in Australia, can be obtained optically pure regardless of the amount of base used during isolation.