NH2+? R NADH R NAD 6.Rank the following heterocycles in decreasing order of reactivity in electrophilic aromatic substitution: O O H A)I>Ⅱ>ⅢB)Ⅱ>I>ⅢC)Ⅲ>I>ⅡD)I>I>IE)I >>Ⅱ Ans: 7.Which atom in the following heterocycle would be the most basic? g A)A B)B C)C D)D E)E Ans:B Page3 Page 3 5. In a formal sense, what must be included to balance the reaction whereby NADH becomes aromatic? N R C O NH2 N + R C O NH2 H H + ? NADH NAD A) H+ B) Hï C) Hñ D) H2 E) H2O Ans: C 6. Rank the following heterocycles in decreasing order of reactivity in electrophilic aromatic substitution: OSN I II III H A) I > II > III B) II > I > III C) III > I >> II D) III > II > I E) I > III > II Ans: C 7. Which atom in the following heterocycle would be the most basic? N CH3 N O N N CH3 A B D C E A) A B) B C) C D) D E) E Ans: B