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Author Topic: Allylcatechol -> safrole: Critique my schematic  (Read 170 times)

Carrion Fairy

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Allylcatechol -> safrole: Critique my schematic
« on: March 14, 2009, 03:41:28 AM »
In a 1L two-neck RBF is placed 200ml DMSO, 40g K2CO3, 2g CuO, 40g CH2I2, and 20g allyl-catechol.

The flask is equipped with a reflux condenser and a rubber septum and needle arrangement for nitrogen inlet.

N2 flow is started, and the flask is then heated to 120-125degC and maintained at that temperature until it is apparent that reaction is no longer proceeding - static colour?

The reaction mixture is then cooled to room temperature and extracted with 3 x 40ml ether. These ethereal extractions are then washed with 20ml 3% HCl, 20ml 3% NaOH, then 20ml water.
The ethereal solution of safrole is then dried over Na2SO4, then vacuum distilled. The ether may thus be recycled.

Questions:
Can I use DCM instead of ether?
Are my volumes ok for the extractions and washes?

Douchermann

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Re: Allylcatechol -> safrole: Critique my schematic
« Reply #1 on: March 17, 2009, 03:40:30 AM »
I would not suggest substituting DCM.  Also, thank goodness you're using methylene iodide as opposed to methylene chloride.  Very little yield is obtained with methylene chloride due to the low reaction temp, because of it's reflux temperature.  This reaction actually does work, I have done it before, but with DCM instead of DIM, bringing my yeild down to around 5g from some unreasonable amount of eugenol to start with.  Again, I wish you luck

v16

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Re: Allylcatechol -> safrole: Critique my schematic
« Reply #2 on: May 02, 2009, 04:51:16 AM »
DCM can be used, but you need a way to introduce it at the bottom of your flask, so that it mixes through out as it turn to gas. A very smart person turned me on to this.  I have used a dean stark with a small peristaltic pump to allow it to reflux and still be introduced right at the stir bar.  Yields are good, >80% when pure DCM is used. (IE don't distill it, buy it)

But no doubt DIM is superior.


Why not use a PTC?  I have good results with this and DCM and dihydroxy's.  Just takes some tweaking.  Once you get it it is rock solid.  You can make some very nice smelling things this way.



Douchermann

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Re: Allylcatechol -> safrole: Critique my schematic
« Reply #3 on: May 02, 2009, 05:44:54 AM »
Quote from: v16 on May 02, 2009, 04:51:16 AM
DCM can be used, but you need a way to introduce it at the bottom of your flask, so that it mixes through out as it turn to gas. A very smart person turned me on to this.  I have used a dean stark with a small peristaltic pump to allow it to reflux and still be introduced right at the stir bar.  Yields are good, >80% when pure DCM is used. (IE don't distill it, buy it)


That sounds really interesting.  So then we would be talking stoicheometric quantities as opposed to using it as a solvent I assume.  What kind of flow were you using?

v16

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Re: Allylcatechol -> safrole: Critique my schematic
« Reply #4 on: May 02, 2009, 05:50:59 AM »
oh yeah, see the posts over at SM.  I have had good luck with either DMSO/KOH or PTC/NaOH systems.  You don't want to use it a solvent in the system, you will get alot of doublets.  1.1 to 1.2 molar equivalents.


flow rate needs to be adjusted to your reflux rate.  I just try to keep about 2 mls in the bottom of the trap at all times.  Flow rate is not that critical, I just tried to make sure it wasn't so fast that I was pumping a lot of air.


Oh, and use a nitrogen ATM!!!



Enkidu

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Re: Allylcatechol -> safrole: Critique my schematic
« Reply #5 on: May 02, 2009, 06:54:25 AM »
What is the purpose of the copper(II) oxide in this reaction? Some type of oxidation inhibitor?

v16

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Re: Allylcatechol -> safrole: Critique my schematic
« Reply #6 on: May 02, 2009, 08:04:53 AM »
catalyst.

zzhuchila_clocker

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Re: Allylcatechol -> safrole: Critique my schematic
« Reply #7 on: May 02, 2009, 08:08:40 AM »
catalyst for what? sn2 reaction?
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zzhuchila_clocker

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Re: Allylcatechol -> safrole: Critique my schematic
« Reply #8 on: May 02, 2009, 08:13:37 AM »
i wonder if the same procedure would work with 3,4-DHP2P. and also PTC procedure. which one is better for 3,4DHP2P, or it does not matter?
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v16

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Re: Allylcatechol -> safrole: Critique my schematic
« Reply #9 on: May 02, 2009, 08:18:28 AM »
im not sure the mechanism has been worked out. but yes that would be my guess. there are a series of papers that looked at different metals acting as catalysts in the methylenation reaction. (I think, its been a while since I read all this stuff)

if I remember right bronze was another one.

they aren't needed in the PTC reaction at all.  I never used them in the DMSO...KOH is fine too.

i don't think the side chain matters for this reaction.  Strong base shouldn't effect the alkene or the ketone.

zzhuchila_clocker

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Re: Allylcatechol -> safrole: Critique my schematic
« Reply #10 on: May 02, 2009, 08:40:38 AM »
Thanks, that does make sence. I was just not sure about the acidic protons of ketone that could cause side reactions. But if that is not happening, its great.
Who stuff the banks? Who staff the party ranks? More for Gore or the son of a drug lord?
None of the above, fuck it, cut the cord!
Lights out.. guerrilla radio
Turn that shit up
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