CEMISTRY 314-01 MIDTERM # 4 April 1, 2003 Statistics: Average: 87 pts (72%); ighest: 116 pts (97%); Lowest: 49 pts (41%) umber of students performing at or above average: 13 (62%) 1. (9 pts) Mark as true (T) or false (F) the following statements. Do not explain! (F) Fischer esterification occurs only in strongly basic conditions; (F) Amides are less reactive than acid chlorides but more reactive than esters; (T) Saponification is the process of base-catalyzed hydrolysis of esters; (F) Lactones are intramolecular amides; (F) Primary amines are molecules in which the amino group is bound to a primary carbon; (T) The value of pk b decreases with an increasing strength of the base; (T) Primary amines can serve as hydrogen bond donors and hydrogen bond acceptors; (T) Secondary amines are stronger bases than primary amines; (F) Michael addition reactions give 1,2-addition products; 2. Circle all that apply: A. (3 pts) The following reactions CAT be used to generate esters: a. Base-catalyzed reaction of carboxylic acid and alcohol; b. Reaction of acid chloride and alcohol; c. Reaction of amide and alcohol; d. Baeyer-Villiger oxidation of ketones; B. (3 pts) The following reactions D T occur with an intermediate formation of enolates: a. Fischer esterification; b. Claisen condensation; c. Dieckmann cyclization; d. Michael addition; C. (3 pts) The following compounds D T decarboxylate upon ing: a. β-ketoacids; b. γ-dicarboxylic acids; c. β-dicarboxylic acids; d. γ -hydroxyacids; 3. (6 pts) Provide an acceptable name for each of the following compounds: 2 C 3 cis-3-aminocyclopentanol phthalic anhydride 6-hexanolide methyl acetoacetate -ethyl-methylcyclohexylamine butylmethylmalonic acid 4. ( pts) Provide the structure of each of the following compounds: C C 2 C C C (E)-2,3-dimethylbutenedioic acid 2,2-dibromocyclopropanamine piperidine 4-methyl-2,6-pyridinedicarboxylic acid -(dimethylamino)-3-hexynoic acid
. ( pts) Rank the following compounds in order of increasing basicity. Do not explain! A. Cyclopentylamine; B. -methylcyclopentylamine; C. Aniline; D. 4-nitroaniline; E. Sodium amide; D < C < A < B < E 6. ( pts) Rank the following compounds in order of increasing acidity. Do not explain! A. Trichloroacetic acid; B. Trifluoroacetic acid; C. Propanoic acid; D. Isopropanol; E. Isopropylamine; D < C < A < B < E 7. Write a complete equation for each of the processes indicated below (TE: Do not write mechanisms!!). A. (4 pts) Reaction of maleic anhydride (cis-butenedioic acid anhydride) with ethanol. + C 2 C 2 B. (4 pts) Saponification of γ-butyrolactone. K 2 K C. (4 pts) Reaction of n-butyl bromide with sodium cyanide, followed by acid hydrolysis; 1. ac C 2. 3 +, D. (4 pts) Reaction of ethyl acetate with ethyl formate in the presence of ac 2 /C 2 ; ac 2 + C 2 C 2 C 2 C 2 8. (18 pts) Predict the principal organic product in each of the following reactions: 1. Mg/ether 2. C 2 3. 3 + C C 1. LiAl 4 2. 3 + C 2 C C C 1. ac 2 /C 2 2. C 1. 2 /P 3 2. 2 C Cl C 3 2 pyridine C 3 C C 3 C 3 2 S 4 CC 3 C 3 1. C 3 Mg 2. 3 +
CC 2 CC 2 1. ac 2 / C 2 2. C 2 C CC 2 1. LDA, 3 C C 3 CC 3 9. (16 pts) Fill in the blanks in the following scheme: 1. ac/dms 2. 3 +, C 3 2 S 4 I C CC 3 1. ac 3 / C 3 2. 3 + C 3 SCl 2 CCl pyr 1. a 2. 3 +, 1. ac 3 / C 3 2. C 3 I C 3 10. (6 pts) Propose a mechanism for the following reaction: C 2 C 3 + C C 2 C 3 Cl C C 3 + C 2-3 + 2 C 3 C C 3 C 2 C C 2 2-3 + C 2 C C 3 3 + C 2 C C 3 - C 2 11. Suggest a plausible synthetic sequence for each of the following transformations. Use any necessary organic or inorganic reagents. A. ( pts)?? C 3
1. 2 ac/dmf 2. 3 +, 3. 2 C 3, 2 S 4 3 CC?? C 2 C 2 CC 3 ac 3 C 3 C 3 B. ( pts) 1. ac/dmf 2. 3 +, 3. C 2, 2 S 4 CC2 ac 2 C 2 C 2 C 2 C 2 12. Use the acetoacetic or malonic ester synthesis to prepare each of the following compounds. Employ any other necessary organic or inorganic reagents. A. ( pts) 3-ethyl--hexen-2-one; C 2 1. ac 2 /C 2 2. C 2 3. ac 2 /C 2 4. B. (4 pts) Cyclopentanecarboxylic acid; C 2 1. K 2. 3 +, - C 2 C 2 C 2 1. ac 2 /C 2 2. C 2 C CC 2 1. K 2. 3 +, - C 2 C 13. (6 pts) The 1 MR spectra of two isomeric compounds, A and B, with molecular formula C 4 6 2 are shown below. Assign the correct structure for each isomer. Compound A C 1 13 12 11 10 9 8 7 6 4 3 2 1
Compound B C 1 13 12 11 10 9 8 7 6 4 3 2 1 14. (4 pts) BUS PRBLEM (In order to receive credit for this problem, it has to be solved entirely!!). In the Stobbe condensation an ester of succinic acid (such as diethyl succinate below) is subjected to base deprotonation and then reacted with a nonenolizable aldehyde or ketone to give a product with a lactone ring. Propose a plausible, detailed mechanism for the Stobbe condensation below. + CC 2 CC 2 ac 2 C 2 CC 2 CC 2 CC 2 ac 2 C 2 CC 2 CC 2 C 2 CC 2 CC 2 CC 2 C 2