[Izyx]

Hi to everyone. I just wanted to check whether I'm on the right track. Attached are image files of compound A and Bisdemethoxycurcumin (BDMC).
I've already attempted the 5 questions but I'm not sure whether I'm doing it right (I left question 2 blank because i don't know the mechanism).

We were asked to:

1.) Propose a synthetic route to synthesize compound A using TOLUENE and compound B,
CH₃CH(OH)C(CH₃)₂CH(OH)CH₃, as the starting materials.

2.) Compound A comprises two aromatic rings with an aliphatic moiety in between them. Show the step-by-step mechanism in the coupling of two aromatic rings with an aliphatic chain to form compound A.

3.) Using the step-by-step mechanism in part 2, identify TWO possible side products that may be formed in the reaction.

4.) Compare the water solubility of compound A with bisdemethoxycurcumin. Which compound has higher solubility? Explain your answer.

5.) Explain why compound A is yellow although toluene and compound B are colorless.


Here's how I did the questions.

Question 1:
    For toluene:
- I did a series of reactions to convert toluene to benzaldehyde
- First, toluene was reacted with Cl₂ in the presence of light (free radical substitution) to get Ph-CH₂-Cl
- The product was, then, reacted with NaOH to get Ph-CH₂-OH and NaCl
- The Ph-CH₂-OH was oxidized using pyridiniumchlorochromate (PCC) to get benzaldehyde

    For compound B:
- Compound B was oxidized using KMnO₄ to get a diketone
- Compound B's name is 3,3-dimethylpentane-2,4-diol if I'm not mistaken (please correct me if I'm wrong)

    For compound A:
- Benzaldehyde was reacted with the diketone via Aldol Condensation in the presence of 10% NaOH (is this a catalyst?).
- We now have compound A

Question 2:
I have no idea how to do the mechanism so I left it blank (for now).

Question 3:
I don't know how to do the mechanism but I do know that one possible side product is H₂O. I don't know what is the other possible side product though.

Question 4:
By comparing the structure of both compound A and BDMC:
- Compound A does not form hydrogen bonding with water because there are no hydrogen atoms directly attached to the oxygen. Only dipole-dipole forces are present
- BDMC can form hydrogen bonding with water molecules because of the presence of OH groups in the compound. The hydrogen directly attached to the oxygen makes it possible for BDMC to have hydrogen bonding with water molecules
- Therefore I conclude that BDMC has higher solubility in water than compound A

Question 5:
- Toluene absorbs UV light which is invisible to our naked eye. UV light appears invisible to the naked eye. Therefore toluene is colorless
- Compound B also does not absorb any part of the spectrum that we can see. Therefore it is also colorless
- I don't know why compound A is yellow. But I'm guessing that it's because compound A has similar molecular structures to BDMC
- And BDMC has similar molecular structures to Curcumin
- Curcumin is yellow


I'm completely lost in question 2 since I do not know how to show them the step-by-step mechanism in the coupling of 2 aromatic rings with an aliphatic compound in between. Do I have to study the step-by-step mechanism in an Aldol Condensation? If yes, where can I find any articles or videos showing the mechanisms in an Aldol Condensation? I hope I can get the other possible side product (aside from H₂O) once I learn the mechanism. Is the 10% NaOH in the reaction in question 1 necessary (I just copied the 10% NaOH from one of the Aldol Condensation I saw in one of the websites I visited)?

Though I know that toluene absorbs UV light, I don't know why it absorbs UV light. Could anyone help me with this? I already searched the internet but all they say is toluene is colorless because it absorbs UV light; no explanation why it absorbs UV light. Same goes for compound B. In fact, I couldn't find compound B in the web. More over, how would I explain why compound A is yellow?

Lastly, does anyone know what's the name of compound A?

Thank you very very much