Chemistry 247 Midterm Examination 3: Nomenclature, Acidity, Synthesis, and Reactions - Pro, Exams of Organic Chemistry

Download Chemistry 247 Midterm Examination 3: Nomenclature, Acidity, Synthesis, and Reactions - Pro and more Exams Organic Chemistry in PDF only on Docsity! /9 Chemistry 247 - Midterm Examination #3 May 10, 2002 Professor Isaacs Name: Circle your section number: 0824 0834 Question Number Points Awarded Maximum Possible 1 ________ 20 2 ________ 20 3 ________ 18 4 ________ 36 5 ________ 10 6 ________ 21 Total ________ out of 125 I pledge on my honor that I have not given or received any unauthorized assistance on this examination. Signature: 2/9 'Question 1: Nomenclature and Acidity. (20 points) a) Draw structures corresponding to the following names. (4 x 2 points) Sodium cyanoborohydride Proline D-Glucose Triethylamine b) Arrange the following compounds in order of increasing acidity. The acidic proton is highlighted in bold. (5 points) NH2 NH B Least acidic NH3 Most acidic c) Protonation of an amide takes place on oxygen rather than on nitrogen. Suggest a reason for this behavior, taking resonance into account. (Problem 24.38, 7 points) H+ H -crH H 5/9 Question 4: Give the major organic products! s), starting materials, or reagents for 9 out of 10 of the following reactions. (9x4 points). EtOH, NaOEt, heat EtO 1) NaOEt (1 eq.) EtOH —————————>- 2) H3 O+ workup EtOH, NaOEt, heat EtOH, NaOEt Cl NaN Ph 2) H2 O, heat NH2 NaBH3 CN,H2 O Hint: Only 1 product oXo- I 6X Xo To X O CM X-o CM X 0 X I o co o~ o CM O co Q) X .E ^'C c\r Q. XOo" ooo 7 co co^« ^r ^^ C\! •"* ' —1 CO o o cO 0 + ' co O CM CO X X co CM goZ c X C/D O<y) CM X CM O Z eo X Z nlO 7/9 Question 5: The structure of the fully protonated form of tyrosine is drawn below along with its values of pKa . (10 points) a) Give the ionization state at pH = 7.0 by filling in the boxes. (3 x 2 points) o __ o pKa = 9. = 2.20 pKa = 10.07 Ionization state at pH = 7.0 b) What is the isoelectric point of tyrosine'.' (4 points)