Question

I need help with 1b,c,e and f all four questions.
1b. NADH is a biological reducing agent that acts as a source of hydride ion (H-) which is a very high energy (reactive) species. Draw arrows to show how this transformation occurs. H H - 1 - 3 HOH RiR2 NH2 Y NH2 R1 R2 MY NH2 - Z- :Z-re NADH NAD+ 1c. What is the driving force for NADH to transform into NAD+. (Hint: what is different about the ring in the two compounds)

Answer 1

1b. NADH is a biological reducing agent that acts as a source of hydride ion (H) which is a very high energy (reactive) species. Draw arrows to show how this transformation occurs. HH1 O=0 Y но н RiR2 NH2 R R2 = Y NH2 NADH NAD Answer Mechanism Hydride Nucleophic addition Protonation HOH RR2 HORR o NH2 D- ZA NADH NADH produces Hydride () ion and it participates in nucloephilic addition with carbonyl 1c. What is the driving force for NADH to transform into NAD . (Hint: what is different about the ring in the two compounds) Answer The driving force for NADH to tranform NAD is aromaticity. Non aromatic ring of NADH is tranfering of Hydride to get aromaticity (more stable) нно "NH2 YNH2 ON- aromaticity R non aromatic ring NAD NADH 1e. Conversely, NAD", will oxidize alcohols (e.g. ethanol) to form carbonyls. Draw out the mechanism for NAD reacting with ethanol (Hint: it involves addition of hydride to NAD). My NH2 NAD* addition of нно X NH2 Hydride NH2 H. CH U-Ź: NAD B-H B = Base 1f. Explain why the hydride attacks that particular carbon in NAD+? Provide an example of an analogous reaction where we have seen attack at the beta position in an alpha/beta unsaturated system to help you explain. N has positive charge so C of C=Nacts electrophilic centre and alpha beta unsatuated double bond is conjugation with CNN+ It exactly mimiking alpha beta unsaturated carbonyl compounds and undergo 1,4-nucleophilic addition, H 0 OYNH, 1,4-nucleophilic addition thermodyanamically favoured