Pre-Lab 2 Quiz: Lab 3- Thiamine Catalyzed Benzoin Condensation.

Name: _________________ Date:_______________

1. What is the structure of Vitamin B ₁? Show conjugate acid(Vitamin B ₁)/base(OH^-) reaction to produce thaizolium and enamine yilide rings.

2. Why is yilide of Vitamin B₁ is stable? (10 pts)

3. Write the step 3 (coupling of two benzaldehyde molecules) in the Vitamin B₁ catalyzed reaction mechanism of the benzoin condensation. (10 pts)

4. How many moles are in 7 mL of benzaldehyde? (10pts)

Density of benzaldehyde (g /mL): 1.04)

Ans:_____________

5. Write the chemical reaction for benzoin condensation. What is the theoretical yield of benzoin starting with 7 mL of benzaldehyde? (10 pts)

Ans: __________________