Chemistry Exam Instructions and Nomenclature

• This exam contains 8 pages, including a title page, a score tally page, and two pages for scratch work
• Your name should be written on every page
• The final answers should be written on the same copy as the exam itself
• An honor code certification should be signed
• During taking the exam, cell phones should be turned off and stored away
• The exam will be collected at 2:45 pm, without exception
• A student ID should be placed on the desk for checking during the exam
• Exams written in pencil, erasable pen, or with white-out will not be regraded
• Books, notes, models, drawing templates, and calculators are not allowed during the exam

Exam Point Allocation

• Page 3 is worth 61 points
• Page 4 is worth 36 points
• Page 5 is worth 40 points
• Page 6 is worth 43 points
• The total possible point value for the exam is 180 points

Question 1a

• Need to draw structure of compound based on IUPAC name: (1E,4Z)-1-bromo-7,7-dimethylnona-1,4-diene

Question 1b

• Provide the IUPAC name of the molecule shown

Question 1c

• Rank the compounds in order of increasing acidity based on the indicated hydrogen atom

Question 1d

• Rank the amines in order of increasing basicity (toward a common acid)

Question 1e

• Sofosbuvir is a medication used for the treatment of hepatitis C, discovered in 2007 and approved in the US in 2013
• Need to assign the absolute configuration (R or S) of the four indicated chiral carbon centers of Sofosbuvir

Question 2a

• Identify two structures that should have identical melting points

Question 2b

• Determine which molecule (A, B, C, D, or none) should show no optical activity in solution

Question 2c

• Identify two molecules that are diastereomers

Question 2d

• (-)-Erithro-a-methylnorepinephrine, or (4-((1R,2S)-1-hydroxy-2-(methylamino)propyl)benzene-1,2-diol, is an intraneural metabolite of L-a-methyldopa
• It is a useful drug employed for the treatment of Parkinson's disease
• The task is to circle the structure corresponding to (-)-Erithro-a-methylnorepinephrine from the 4 representations provided

Question 3

• For each pair of molecules, indicate their relationships as: conformational isomers, enantiomers, diastereomers, structural isomers, identical, or none
• Choose the most specific answer

Question 4

• Complete the equation for the reaction between,label which starting material is the Lewis acid/base, and use curved arrows to show e- flow in reaction
• Show valence electrons for all atoms participating in the reaction, noting formal charges, if any

Question 5

• Consider the structure of 4-(N,N-dimethylamino)pyridine

Question 5a

• Determine how many sp² hybridized nitrogen atoms are present in 4-(N,N-dimethylamino)aniline

Question 5b

• Identify (circle) the least basic nitrogen atom of 4-(N,N-dimethylamino)pyridine and justify the choice

Question 5c

• Draw all the resonance structures of the conjugate acid derived from the most basic nitrogen atom of imidazole
• Show the electron movement using the curved arrows formalism

Question 6

• Of the molecules shown, circle the meso compounds

Question 7

• Consider an acid-base reaction and answer the questions

Question 7a

• Use curved arrows to show how the acid and base react (mechanism of electron movement)

Question 7b

• Draw the products of the reaction (CB = conjugated base; CA = conjugated acid), complete with any charges/lone pairs of electrons

Question 7c

• Given the pKa value for the CA and the approximate equilibrium constant for the reaction, determine the pKa value for A

Question 8

• Consider a molecule and answer the questions

Question 8a

• Determine the number of possible configurational stereoisomers for the molecule

Question 8b

• Determine how many pairs of enantiomers are possible for the molecule shown based on the answer from part "a"

Question 8c

• Draw a proper Fisher projection for D-Galactose ((2R,3S,4S,5R)-2,3,4,5,6-pentahydroxyhexanal)