Question

given the reaction: Reaction of Dimedone and Benzaldehyde (2 Part)

overview Part 1:

Using a Pasteur pipet, add 0.2 g of benzaldehyde to 50 mL Erlenmeyer flask. 2. Add 8 mL of 1:1 ethanol/water and swirl the flask to mix the content. 3. Add 0.6 g of dimedone and 3 drops of piperidine, and 2-3 boiling chips 4. Boil gently for 5 min on a hot plate 6. at the end of 5 minutes let the mixture cool, followed by cooling in an ice bath to complete crystallization5. Collect crystals by vacuum filtration, washing with several 10 mL portions of ice cold 1:1 ethanol: water, Gently break the crystals with a spatula and let them sit on the vacuum for 30 min to dry.

overview Part 2:

Next if 250mg of product (from above) and 10 ml of absoulte enthanol were put into an erenmeyer flask, heated. Then 2.5ml of water and 6 drops of 6M HCL were added. The mixture was left to to continue  boiling. the flask was removed fro heat and water was added dropwise until the mixture becomes cloudy. The product is collected.

Questions:

1. why is it possible for dimedone to have two tauromers?

2. what spectroscopy methods can you use to prove the formation of tautomers?

3. why do you use piperdine during the first step of this reaction? could you use inorganic base instead?

4. what are the differences in IR between benzaldehyde and the product from part 2 (3,3,6,6-tetramethyl-9-phenyl-3,4,5,6,7,9-hexahydro-1h-xanthene-1,8(2h)-dione)

Answer 1