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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: SeriouSyrius on January 05, 2014, 02:32:35 AM

Title: How to obtain (2E, 6E)-2,6-bis(4-hydroxybenzylidene) cyclohexanone?
Post by: SeriouSyrius on January 05, 2014, 02:32:35 AM: Reference on compound: http://www.chemspider.com/Chemical-Structure.1468601.html

I was using benzene to convert it to 4-hydroxybenaldehyde and then I used cyclohexane to convert it to Cyclohexanone.

1 mole of Cyclohexanone + 2 moles of 4-hydroxybenaldehyde ---NaOH(aq)---> (2E, 6E)-2,6-bis(4-hydroxybenzylidene) cyclohexanone

Is this right?
Title: Re: How to obtain (2E, 6E)-2,6-bis(4-hydroxybenzylidene) cyclohexanone?
Post by: discodermolide on January 05, 2014, 04:31:06 AM: I would be more interested to see how you went from benzene to 4-hydroxy-benzaldehyde!
The latter compound is commercially available.
Title: Re: How to obtain (2E, 6E)-2,6-bis(4-hydroxybenzylidene) cyclohexanone?
Post by: SeriouSyrius on January 05, 2014, 06:17:39 AM: (https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fi41.tinypic.com%2Fdyvhp1.jpg&hash=bcc6064c6f6a1ba2081e45e4d3a43e2b0ac00ef3)
Title: Re: How to obtain (2E, 6E)-2,6-bis(4-hydroxybenzylidene) cyclohexanone?
Post by: discodermolide on January 05, 2014, 10:37:39 AM: The last reaction to make the phenol, how do you see this proceeding?
You have an aromatic aldehyde in the presence of conc. NaOH at high temperature, what other reaction could occur here?
Title: Re: How to obtain (2E, 6E)-2,6-bis(4-hydroxybenzylidene) cyclohexanone?
Post by: Altered State on January 05, 2014, 11:04:28 AM: I'd rather go for a diazonium salt hydrolyisis, check Sandmeyer reaction.
Title: Re: How to obtain (2E, 6E)-2,6-bis(4-hydroxybenzylidene) cyclohexanone?
Post by: SeriouSyrius on January 06, 2014, 06:18:21 AM: Quote from: discodermolide on January 05, 2014, 10:37:39 AM
The last reaction to make the phenol, how do you see this proceeding?
You have an aromatic aldehyde in the presence of conc. NaOH at high temperature, what other reaction could occur here?

I got the last reaction from my notes. It says "Sodium Phenoxide + HCl(H+)---->Phenol"

As for the aromatic aldehyde with NaOH I think Aldol Reaction will occur? So I guess this part is wrong.

How about this method? I think i used diazonium salt to get OH.

(https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fi44.tinypic.com%2F2nr2u8.jpg&hash=f2142105171cf2a873c07fc1b10ab8d5166f0ef6)
Title: Re: How to obtain (2E, 6E)-2,6-bis(4-hydroxybenzylidene) cyclohexanone?
Post by: discodermolide on January 06, 2014, 07:19:41 AM: I meant the substitution of Cl with OH.
How do you think this proceeds?
Aromatic aldehydes undergo a named reaction in the presence of strong base, can you think of it? Named after a famous Italian chemist from the 1800s.
Title: Re: How to obtain (2E, 6E)-2,6-bis(4-hydroxybenzylidene) cyclohexanone?
Post by: SeriouSyrius on January 06, 2014, 07:46:33 AM: Quote from: discodermolide on January 06, 2014, 07:19:41 AM
I meant the substitution of Cl with OH.
How do you think this proceeds?
Aromatic aldehydes undergo a named reaction in the presence of strong base, can you think of it? Named after a famous Italian chemist from the 1800s.

I don't really get what you mean. All i know is the substitution of Cl with OH is to get alcohol and so I can reduce the primary alcohol to aldehyde. For the reaction name, I got no idea. All I can think of is Aldol Reaction.
Title: Re: How to obtain (2E, 6E)-2,6-bis(4-hydroxybenzylidene) cyclohexanone?
Post by: discodermolide on January 06, 2014, 07:52:50 AM: The reaction I am talking about is the Cannizzaro reaction of aromatic aldehydes to give the benzyl alcohol and the benzoic acid. http://en.wikipedia.org/wiki/Cannizzaro_reaction (http://en.wikipedia.org/wiki/Cannizzaro_reaction)

I was just wondering if you knew how the substitution of Cl for OH worked (the reaction mechanism).
Title: Re: How to obtain (2E, 6E)-2,6-bis(4-hydroxybenzylidene) cyclohexanone?
Post by: SeriouSyrius on January 06, 2014, 07:56:57 AM: Quote from: discodermolide on January 06, 2014, 07:52:50 AM
The reaction I am talking about is the Cannizzaro reaction of aromatic aldehydes to give the benzyl alcohol and the benzoic acid. http://en.wikipedia.org/wiki/Cannizzaro_reaction (http://en.wikipedia.org/wiki/Cannizzaro_reaction)

I was just wondering if you knew how the substitution of Cl for OH worked (the reaction mechanism).

Oh. I didn't hear before Cannzizzaro reaction. I'm still studying for Organic Chemistry. Currently studying about Benzene, Phenol, Aniline and Aldol Condensation. So how was my method of getting (2E, 6E)-2,6-bis(4-hydroxybenzylidene) cyclohexanone? It's a really important assignment and I need to try to get much information about it as I can. This is my overall method:

(https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fi43.tinypic.com%2F2qu2910.jpg&hash=3a0622b67699cbdb7e71c01f9eb32b9c4a8c9b3d)
Title: Re: How to obtain (2E, 6E)-2,6-bis(4-hydroxybenzylidene) cyclohexanone?
Post by: discodermolide on January 06, 2014, 08:06:36 AM: The new method certainly avoids problems with the Cannizzaro reaction. Using the diazonium salt is better.

The mechanism I was talking about, Cl going to OH (the original you showed) may go as I suggest in the attachment.
However I believe I am a bit ahead of your classes, sorry for any confusion I have caused. Anyway you have learnt a new reaction for yourself, and that's good.
Title: Re: How to obtain (2E, 6E)-2,6-bis(4-hydroxybenzylidene) cyclohexanone?
Post by: SeriouSyrius on January 06, 2014, 08:14:26 AM: Quote from: discodermolide on January 06, 2014, 08:06:36 AM
The new method certainly avoids problems with the Cannizzaro reaction. Using the diazonium salt is better.

The mechanism I was talking about, Cl going to OH (the original you showed) may go as I suggest in the attachment.
However I believe I am a bit ahead of your classes, sorry for any confusion I have caused. Anyway you have learnt a new reaction for yourself, and that's good.

It's alright. So if I'm not wrong the first overall method is alright but it's just that I have to use the method you attached? And the second method is also right?
Title: Re: How to obtain (2E, 6E)-2,6-bis(4-hydroxybenzylidene) cyclohexanone?
Post by: discodermolide on January 06, 2014, 08:17:26 AM: I would go for the diazonium salt method. It is longer but avoids the side reaction I mentioned (Cannizzaro).
Title: Re: How to obtain (2E, 6E)-2,6-bis(4-hydroxybenzylidene) cyclohexanone?
Post by: SeriouSyrius on January 06, 2014, 08:19:40 AM: Last question, about the combining of cyclohexanone with 4-hydroxybenaldehyde is there such reaction and is water the only side product? I found the reaction online so i'm wondering if it can be trusted.
Title: Re: How to obtain (2E, 6E)-2,6-bis(4-hydroxybenzylidene) cyclohexanone?
Post by: discodermolide on January 06, 2014, 08:24:06 AM: That is the aldol reaction. This is a standard method for the preparation of such compounds. Analogues of curcumin, an interesting compound for various pharmacological applications, cancer for example.
Title: Re: How to obtain (2E, 6E)-2,6-bis(4-hydroxybenzylidene) cyclohexanone?
Post by: SeriouSyrius on January 06, 2014, 08:25:41 AM: Quote from: discodermolide on January 06, 2014, 08:24:06 AM
That is the aldol reaction. This is a standard method for the preparation of such compounds. Analogues of curcumin, an interesting compound for various pharmacological applications, cancer for example.

Alright. Thanks! Helped a lot. :) :) :)
Title: Re: How to obtain (2E, 6E)-2,6-bis(4-hydroxybenzylidene) cyclohexanone?
Post by: kriggy on January 07, 2014, 11:40:36 AM: In the last attempt I belive you missdrew one hydroxy goup in your product. Shouldnt it be in para position instead of meta?
Title: Re: How to obtain (2E, 6E)-2,6-bis(4-hydroxybenzylidene) cyclohexanone?
Post by: SeriouSyrius on January 11, 2014, 08:28:27 AM: Apparently the method I used isn't really good. I need to come up with a better one. I was thinking about this.

(https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fi42.tinypic.com%2Fm8mef9.jpg&hash=8d0a1100099a7e2c2d174fc6f496f6e1e81156e5)

As for the picture below, I was asked to think about the 3 side products but after reading the notes I had about aldol reaction, I can't seem to find the side products. All I can think of is the mixed aldol reaction but the problem now is there are 0 alpha-hydrogen in 4-hydroxybenzaldehyde and 4 alpha-hydrogen in cyclohexanone. How does the mixed aldol reaction work when 4-hydroxybenzaldehyde have 0 alpha-hydrogen???

(https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fi39.tinypic.com%2Fofzihx.jpg&hash=51da77ecd79eb36f8dc391edc1ce5ca7bead09bd)
Title: Re: How to obtain (2E, 6E)-2,6-bis(4-hydroxybenzylidene) cyclohexanone?
Post by: discodermolide on January 11, 2014, 08:52:17 AM: The mixed aldol reaction is possible with cyclohexanone.
You take the product from the aldol of cyclohexanone and the benzaldehyde and react it with cyclohexanone. See if you can come up with the other possibilities.

I'm sorry but your new scheme is worse than the one you gave in. The acid chloride of formic acid, I'm not sure it exists. Try and find a route by making a benzoate from benzene.
Title: Re: How to obtain (2E, 6E)-2,6-bis(4-hydroxybenzylidene) cyclohexanone?
Post by: SeriouSyrius on January 11, 2014, 09:52:11 AM: The final product of the aldol of Cyclohexanone and 4-hydroxybenaldehyde doesn't have any alpha-carbon also. Unless I bond it to only 1 side of cyclohexanone. Can I do that?

(https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fi43.tinypic.com%2F301euty.jpg&hash=ad9375a9cf8c4bb115fb0a921b493ddae690de23)
Title: Re: How to obtain (2E, 6E)-2,6-bis(4-hydroxybenzylidene) cyclohexanone?
Post by: discodermolide on January 11, 2014, 10:14:47 AM: This compound is a possible intermediate:
$O=C1CCCC/C1=C\C2=CC=C(O)C=C2$

and can undergo an aldol with the aldehyde or cyclohexanone.
Title: Re: How to obtain (2E, 6E)-2,6-bis(4-hydroxybenzylidene) cyclohexanone?
Post by: SeriouSyrius on January 11, 2014, 11:03:08 AM: Oh so this is one of the side product? Sorry, need you to tilt your head to the left. :P

(https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fi39.tinypic.com%2F25r2lb9.jpg&hash=7333753e9b0c151b2bb8447fdbbde0b352c4e7fd)

What about the previous picture I send? The side product I written there.
Title: Re: How to obtain (2E, 6E)-2,6-bis(4-hydroxybenzylidene) cyclohexanone?
Post by: discodermolide on January 11, 2014, 11:12:23 AM: Yes that is also a possible side product.
Title: Re: How to obtain (2E, 6E)-2,6-bis(4-hydroxybenzylidene) cyclohexanone?
Post by: SeriouSyrius on January 11, 2014, 11:23:00 AM: Alright I got understand the method but I can't seem to form the 3rd product. Unless this can be the product?

(https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fi44.tinypic.com%2F5frk2v.png&hash=9b3ea1928ecbda1506a917d2ac5bb5b27c94f3a7)

If that is not one of it, how about I switch the 2 side around but I don't think it make a difference? :/

(https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fi44.tinypic.com%2F2uz54bp.jpg&hash=8340e344d456f924af6b4faeae3724e8b8bb996d)