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CHM 332 Name_______________________________ EXAMINATION - Ch 20 and 21 All answers should be written on the exam in the spaces provided. Clearly indicate your answers in the spaces provided; if I have to guess as to what or where your answer is, it is wrong. Where applicable, outline the logic or mystical principle you used to arrive at your answer, as partial credit may be awarded for correct approaches. You may assume that standard work-up conditions (i.e. those required to obtain a stable, neutral product, such as aqueous acid for example) follow each reaction on the exam. Clearly indicate stereochemistry where appropriate. Be careful not to show stereochemistry where none exists. You are strongly advised to read through the entire exam before you begin. (1)..21 pts....................._____ (2)..15 pts....................._____ (3)..18 pts....................._____ (4)..18 pts....................._____ (5)..10 pts……….……_____ (6)..10 pts……….……_____ (7)..8 pts………...……_____ _______________________ TOTAL (100 pts).........._____ Percentage …………..._____ 1. [21 pts] Fill in the necessary reagents or products to complete each of the following reactions in the formation of 1-phenyl-2-butanol: A D B C PBr3 1. NaHCO3 2. CH3I NaBH4 LiAlH(OtBu)3 G F E OH DIBAH, -78C 1-phenyl-2-butanol 2. [15 pts] Propose a logical stepwise mechanism for formation of the transesterification of tert-butyl benzoate to methyl benzoate, using an acid catalyst and methanol solvent. O O O CH3OH, H+ OCH3 + HO 3. [21 pts] Indicate the major product that forms in each of the following reactions. You may assume standard conditions to achieve a neutral stable product. a. O POCl3 NH2 b. N LiAlH4 c. O mCPBA d. O LAH H2N e. O O Cl OH f. O O O O O OH g. O O O LiAlH4 OH 4. [18 pts] Synthesis problems - Devise a series of reactions to synthesize the following molecules. Partial credit will be given for approaches without reagents, if intermediate structures are shown. a. [4 pts] N OH b. [6 pts] O O H N H c. [8 pts] Hint: You MUST form a carboxylic acid first! O O Br O 5. [10 pts] Nomenclature section: Circle the name that is correct for each molecule, based on IUPAC rules. i. O HO O a. 4-keto-5-methylhexan-1-carboxylic acid b. 4-oxo-5-methylhexanoic acid c. 5-methyl-4-oxohexanoic acid d. 3-oxo-4-methylpentanoic acid ii. O O a. b. c. d. 4-methylheptanoate 4-methylbutanoate pentyl 4-metylhexanoate 3-methylbutyl 4-methylhexanoate isobutyl 4-methylhexanoate iii. O OH H3CHN a. b. c. d. 5-hydroxy-1-methylaminohexanone 5-hydroxy-1-methylhexanamine N,5-hydroxymethylhexanamide 5-hydroxy-N-methylhexanamide iv. Cl O Br a. 4,4-dimethyl-3-chlorohexanoyl bromide b. 1-bromo- 4,4-dimethylhexanoyl-3-chloride c. 3-chloro-4,4-dimethylhexanoyl bromide d. 1-bromo-3-chloro-4,4-dimethyl-1-hexanone. v. O O O a. sec-butanoic propanoic anhydride b. ethanoic sec-butanoic anhydride c. acetic isopropanoic anhydride d. isobutanoic propanoic anhydride 6. [10 pts] Identify the functional groups that form in each of the following reactions: a. addition of a Grignard reagent to a nitrile _________________________ b. addition of LAH to an amide _________________________ c. addition of (CH3)2CuLi to an acid chloride _________________________ d. addition of CH2N2 to a carboxylic acid _________________________ e. addition of aqueous acid to an acid anhydride _________________________ 7. [16 pts] Thought Provoking Questions (a.k.a. Short Answers): Choose 4 of the 6 following questions. a. Give two reasons why DIBAH reduces esters to aldehydes and not alcohols. b. Experiments show that the molecular weight of acetic acid in the vapor state is approximately 120. Explain the discrepancy between this experimental value and the true value of approximately 60. c. Explain why the addition of water to an amide to form a carboxylic acid is not catalytic in acid, unlike a reaction such as the Fischer esterification. O H2O, H+ NH2 O OH + NH3 d. Explain the two factors that make a carboxylic acid, such as benzoic acid, acidic.