Explain why the pKa of the COOH group of glycine is much lower than the pKa of the COOH

Give the IUPAC name for each compound. a. CH3CH2CH2C(CH3)2CH2COOH d. O OH b. CH3CH(Cl)CH2CH2COOH c. (CH3CH2)2CHCH2CH(CH2CH3)COOH

Give the structure corresponding to each IUPAC name. a. 2-bromobutanoic acid d. 2-sec-butyl-4,4-diethylnonanoic acid b. 2,3-dimethylpentanoic acid e. 3,4-diethylcyclohexanecarboxylic acid c. 3,3,4-trimethylheptanoic acid f. 1-isopropylcyclobutanecarboxylic acid

Draw the structure corresponding to each common name: a. -methoxyvaleric acid c. ,-dimethylcaproic acid b. -phenylpropionic acid d. -chloro--methylbutyric acid

Give an IUPAC and common name for each of the following naturally occurring carboxylic acids: (a) CH3CH(OH)CO2H (lactic acid); (b) HOCH2CH2C(OH)(CH3)CH2CO2H (mevalonic acid).

Give the IUPAC name for each metal salt of a carboxylate anion: (a) C6H5CO2 Li+ ; (b) HCO2 Na+ ; (c) (CH3)2CHCO2 K+ ; (d) (CH3CH2)2CHCH2CH(Br)CH2CH2CO2 Na+ .

Depakote, a drug used to treat seizures and bipolar disorder, consists of a mixture of valproic acid [(CH3CH2CH2)2CHCO2H] and its sodium salt. Give IUPAC names for each of these compounds.

Rank the following compounds in order of increasing boiling point. Which compound is the most water soluble? Which compound is the least water soluble? CH2COOH COOCH3 CH2CH2CH2OH

Explain how you could use IR spectroscopy to distinguish among the following three compounds. O O OH C CH3CH2CH2CH2 OCH3 O C CH3CH2CH2CH2 OH

Identify the structure of a compound of molecular formula C4H8O2 that gives the following 1 H NMR data: 0.95 (triplet, 3 H), 1.65 (multiplet, 2 H), 2.30 (triplet, 2 H), and 11.8 (singlet, 1 H) ppm.

How many tetrahedral stereogenic centers does PGF2 contain? Draw its enantiomer. How many of its double bonds can exhibit cis-trans isomerism? Considering both its double bonds and its tetrahedral stereogenic centers, how many stereoisomers are possible for PGF2?

What alcohol can be oxidized to each carboxylic acid? a. OH O b. (CH3)2CHCOOH c. COOH

Identify AD in the following reactions. a. H2SO4, H2O A Na2Cr2O7 COOH c. O2N KMnO4 C COOH b. B CH3COOH (2 equiv) [1] O3 [2] H2O d. H2SO4, H2O CO2H O D CrO3

Draw the products of each acidbase reaction. a. NaOH COOH c. CH3 C CH3 CH3 OH NaH b. CH3 NaOCH3 OH d. NaHCO3 COOH

Given the pKa values in Appendix A, which of the following bases are strong enough to deprotonate CH3COOH: (a) F ; (b) (CH3)3CO ; (c) CH3 ; (d) NH2; (e) Cl ?

Rank the labeled protons (HaHc) in mandelic acid, a naturally occurring carboxylic acid in plums and peaches, in order of increasing acidity. Explain in detail why you chose this order. OHb Ha OHc O mandelic acid

Match each of the following pKa values (3.2, 4.9, and 0.2) to the appropriate carboxylic acid: (a) CH3CH2COOH; (b) CF3COOH; (c) ICH2COOH.

Explain why HCOOH (formic acid) has a lower pKa than acetic acid (3.8 versus 4.8).

Rank the compounds in each group in order of increasing acidity. a. CH3COOH, HSCH2COOH, HOCH2COOH b. ICH2COOH, I2CHCOOH, ICH2CH2COOH

Substituted phenols show substituent effects similiar to substituted benzoic acids. Should the pKa of phenol A, one of the naturally occurring phenols called urushiols isolated from poison ivy, be higher or lower than the pKa of phenol (C6H5OH, pKa = 10)? Explain. OH HO A

Which of the following pairs of compounds can be separated from each other by an extraction procedure? a. CH3(CH2)6COOH and CH3CH2CH2CH2CH CH2 b. CH3CH2CH2CH2CH CH2 and (CH3CH2CH2)2O c. CH3(CH2)6COOH and NaCl d. NaCl and KCl

Explain why two low molecular weight organic compounds such as CH3CH2COOH and CH3CH2CH2OH can't be separated by an aqueous extraction technique.

Two other commonly used sulfonic acids are methanesulfonic acid (CH3SO3H) and trifl uoromethanesulfonic acid (CF3SO3H). Which has the weaker conjugate base? Which conjugate base is the better leaving group? Which of these acids has the higher pKa?

Draw both enantiomers of each amino acid and label them as R or S: (a) phenylalanine; (b) methionine

Explain why amino acids, unlike most other organic compounds, are insoluble in organic solvents like diethyl ether.

Draw the positively charged, neutral, and negatively charged forms for the amino acid glycine. Which species predominates at pH 11? Which species predominates at pH 1?

The pKa values for the carboxy and ammonium protons of phenylalanine are 2.58 and 9.24, respectively. What is the isoelectric point of phenylalanine? Draw the structure of phenylalanine at its isoelectric point.

Explain why the pKa of the COOH group of glycine is much lower than the pKa of the COOH of acetic acid (2.35 compared to 4.8).

Draw the structure corresponding to each name. a. 3,3-dimethylpentanoic acid e. m-hydroxybenzoic acid i. 2,2-dichloropentanedioic acid b. 4-chloro-3-phenylheptanoic acid f. o-chlorobenzoic acid j. 4-isopropyl-2-methyloctanedioic acid c. (2R)-2-chloropropanoic acid g. potassium acetate d. ,-dichloropropionic acid h. sodium -bromobutyrate

Draw the structures and give the IUPAC names for the carboxylic acids having molecular formula C5H10O2. Then give the IUPAC names for the sodium salts that result from treatment of each carboxylic acid with NaOH.

Rank the compounds in each group in order of increasing boiling point. a. CH3CH2CH2CH2COOH, (CH3CH2CH2)2O, CH3(CH2)5OH b. CH3COCH2CH(CH3)2, (CH3)2CHCH2COOH, (CH3)2CHCH2CH(OH)CH3

Draw the organic products formed in each reaction. a. OH CrO3 H2SO4, H2O c. C H [1] O3 [2] H2O C b. KMnO4 (CH3)2CH CH3 d. CH3(CH2)6CH2OH H2SO4, H2O Na2Cr2O7

Identify the lettered compounds in each reaction sequence. a. CH2 A B [1] BH3 [2] H2O2, HO CrO3 H2SO4, H2O c. G H (CH3)2CHCl AlCl3 KMnO4 b. HC CH C DE + F [1] NaNH2 [2] CH3I [1] O3 [2] H2O [1] NaNH2 [2] CH3CH2I

Using the pKa table in Appendix A, determine whether each of the following bases is strong enough to deprotonate the three compounds listed below. Bases: [1] OH; [2] CH3CH2 ; [3] NH2; [4] NH3; [5] HC C . a. CH3 COOH pKa = 4.3 b. Cl OH pKa = 9.4 c. (CH3)3COH pKa = 18

Draw the products of each acidbase reaction, and using the pKa table in Appendix A, determine if equilibrium favors the reactants or products. a. KOC(CH3) COOH + 3 d. CH3 COOH + CH3Li b. OH + NH3 e. (CH3)2CHCH2OH + NaH c. OH + NaNH2 f. CH3 OH + Na2CO3

Which compound in each pair has the lower pKa? Which compound in each pair has the stronger conjugate base? a. or COOH CH2OH c. CH or 3 COOH Cl COOH b. ClCH2COOH or FCH2COOH d. NCCH2COOH or CH3COOH

Rank the compounds in each group in order of increasing acidity. a. COOH Cl COOH COOH Br c. COOH CH3 COOH CF3 COOH b. CH3 OH O2N OH Cl OH d. Br NO2 OH O2N OH O2N OH

Match the pKa values to the appropriate structure. pKa values: 0.28, 1.24, 2.66, 2.86, and 3.12. Compounds: (a) FCH2COOH; (b) CF3COOH; (c) F2CHCOOH; (d) ICH2COOH; (e) BrCH2COOH.

Although codeine occurs in low concentration in the opium poppy, most of the codeine used in medicine is prepared from morphine (the principal component of opium) by the following reaction. Explain why selective methylation occurs at only one OH in morphine to give codeine. Codeine is a less potent and less addictive analgesic than morphine. H H O codeine N CH3 CH3O HO H H O morphine N CH3 HO HO [1] KOH [2] CH3I

Explain each statement. a. The pKa of p-nitrophenol is lower than the pKa of phenol (7.2 vs. 10). b. The pKa of p-nitrophenol is lower than the pKa of m-nitrophenol (7.2 vs. 8.3).

Explain the following statement. Although 2-methoxyacetic acid (CH3OCH2COOH) is a stronger acid than acetic acid (CH3COOH), p-methoxybenzoic acid (CH3OC6H4COOH) is a weaker acid than benzoic acid (C6H5COOH).

Explain why the pKa of compound A is lower than the pKa's of both compounds B and C. CO2H O CO2H N H CO2H O pKa = 3.2 pKa = 3.9 pKa = 4.4

Rank the following compounds in order of increasing acidity and explain in detail your choice of order. O2N CO2H C CO2H D O2N CO2H E

Explain the following result. Acetic acid (CH3COOH), labeled at its OH oxygen with the uncommon 18O isotope, was treated with aqueous base, and then the solution was acidifi ed. Two products having the 18O label at different locations were formed. + [1] NaOH [2] H3O+ * labeled O atom The label is now in two different locations. CH3 OH * C O CH3 OH C O * CH3 OH C O

Draw all resonance structures of the conjugate bases formed by removal of the labeled protons (Ha, Hb, and Hc) in 1,3-cyclohexanedione and acetanilide. For each compound, rank these protons in order of increasing acidity and explain the order you chose. a. O O Ha Hc Hb 1,3-cyclohexanedione b. O N Hb Hc acetanilide Ha

As we will see in Chapter 23, C H bonds are sometimes more acidic than O H bonds. Explain why the pKa of CH2(CHO)2 is lower than the pKa of HO(CH2)3OH (9 vs. 16).

Identify X in the following equation, and explain how hexanoic acid, the chapter-opening molecule, is formed by this stepwise reaction sequence. CH3COOH X [2] H3O+ strong base (2 equiv) [1] CH3CH2CH2CH2Br CH3CH2CH2CH2CH2COOH hexanoic acid

The pKa of acetamide (CH3CONH2) is 16. Draw the structure for its conjugate base and explain why acetamide is less acidic than CH3COOH.

Write out the steps needed to separate hydrocarbon A and carboxylic acid B by using an extraction procedure. A COOH

Because phenol (C6H5OH) is less acidic than a carboxylic acid, it can be deprotonated by NaOH but not by the weaker base NaHCO3. Using this information, write out an extraction sequence that can be used to separate C6H5OH from cyclohexanol. Show what compound is present in each layer at each stage of the process, and if it is present in its neutral or ionic form.

Can octane and 1-octanol be separated using an aqueous extraction procedure? Explain why or why not.

Identify each compound from its spectral data. a. Molecular formula: C3H5ClO2 IR: 35002500 cm1, 1714 cm1 1 H NMR data: 2.87 (triplet, 2 H), 3.76 (triplet, 2 H), and 11.8 (singlet, 1 H) ppm b. Molecular formula: C8H8O3 IR: 35002500 cm1, 1688 cm1 1 H NMR data: 3.8 (singlet, 3 H), 7.0 (doublet, 2 H), 7.9 (doublet, 2 H), and 12.7 (singlet, 1 H) ppm c. Molecular formula: C8H8O3 IR: 35002500 cm1, 1710 cm1 1 H NMR data: 4.7 (singlet, 2 H), 6.97.3 (multiplet, 5 H), and 11.3 (singlet, 1 H) ppm

Use the 1 H NMR and IR spectra given below to identify the structures of two isomers (A and B) having molecular formula C4H8O2. Compound A: 1 H ppm 1H NMR of A 876543210 3 H 2 H 2 H Wavenumber (cm1) % Transmittance 100 50 0 4000 3000 3500 2000 1000 2500 1500 500 IR [A] Compound B: ppm 1H NMR of B 12 10 8 6 4 2 0 1 H 1 H 6 H very broad singlet Wavenumber (cm1) % Transmittance 100 50 0 4000 3500 3000 2500 2000 1500 1000 500

An unknown compound C (molecular formula C4H8O3) exhibits IR absorptions at 36002500 and 1734 cm1, as well as the following 1 H NMR spectrum. What is the structure of C? 1H NMR of C 3 H ppm 12 10 8 6 4 2 0

Propose a structure for D (molecular formula C9H9ClO2) consistent with the given spectroscopic data. 13C NMR signals at 30, 36, 128, 130, 133, 139, and 179 ppm 1H NMR of D ppm 12 10 8 6 4 2 0

A monomer needed to synthesize polyethylene terephthalate (PET), a polymer used to make plastic sheeting and soft drink bottles (Section 22.16), shows a strong absorption in its IR spectrum at 1692 cm1 and two singlets in its 1 H NMR spectrum at 8.2 and 10.0 ppm. What is the structure of this monomer (molecular formula C8H6O4)?

Match the 13C NMR data to the appropriate structure. Spectrum [1]: signals at 14, 22, 27, 34, 181 ppm COOH COOH O OH AB C Spectrum [2]: signals at 27, 39, 186 ppm Spectrum [3]: signals at 22, 26, 43, 180 ppm

-Butyrolactone (C4H6O2, GBL) is a biologically inactive compound that is converted to the biologically active recreational drug GHB (Section 19.5) by a lactonase enzyme in the body. Since -butyrolactone is more fat soluble than GHB, it is more readily absorbed by tissues and thus produces a faster onset of physiological symptoms. -Butyrolactone shows an absorption in its IR spectrum at 1770 cm1 and the following 1 H NMR spectral data: 2.28 (multiplet, 2 H), 2.48 (triplet, 2 H), and 4.35 (triplet, 2 H) ppm. What is the structure of -butyrolactone?

Threonine is a naturally occurring amino acid that has two stereogenic centers. H2N H C C COOH H OH CH3 threonine C2 a. Draw the four possible stereoisomers using wedges and dashes. b. The naturally occurring amino acid has the 2S,3R confi guration at its two stereogenic centers. Which structure does this correspond to?

Proline is an unusual amino acid because its N atom on the carbon is part of a fi ve-membered ring. H N COOH proline a. Draw both enantiomers of proline. b. Draw proline in its zwitterionic form.

For each amino acid [RCH(NH2)COOH], draw its neutral, positively charged, and negatively charged forms. Which form predominates at pH = 1, 6, and 11? What is the structure of each amino acid at its isoelectric point? a. methionine (R = CH2CH2SCH3) b. serine (R = CH2OH)

Calculate the isoelectric point for each amino acid. a. cysteine: pKa (COOH) = 2.05; pKa (-NH3 + ) = 10.25 b. methionine: pKa (COOH) = 2.28; pKa (-NH3 + ) = 9.21

Lysine and tryptophan are two amino acids that contain an additional N atom in the R group bonded to the carbon. While lysine is classifi ed as a basic amino acid because it contains an additional basic N atom, tryptophan is classifi ed as a neutral amino acid. Explain why this difference in classifi cation occurs. OH C O H2N H N H OH C O H2N H2N H lysine tryptophan

Amino acids can be prepared from -halo carboxylic acids [RCH(X)COOH] by reaction with excess NH3. Why is excess NH3 needed for this reaction?

Explain why using one or two equivalents of NaH results in different products in the following reactions. NaH (1 equiv) NaH (2 equiv) [2] H2O [1] CH3I [2] H2O [1] CH3I HO CH2CH2CH2CH2OH CH3O CH2CH2CH2CH2OH HO CH2CH2CH2CH2OCH3

Although p-hydroxybenzoic acid is less acidic than benzoic acid, o-hydroxybenzoic acid is slightly more acidic than benzoic acid. Explain this result. OH p-hydroxybenzoic acid o-hydroxybenzoic acid HO COOH COOH

2-Hydroxybutanedioic acid occurs naturally in apples and other fruits. Rank the labeled protons (HaHe) in order of increasing acidity and explain in detail the order you chose. 2-hydroxybutanedioic acid OHe HaO HbO Hc O Hd O