Author Topic: Mn(III)-Catalyzed P2P's  (Read 2707 times)

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Bwiti

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Mn(III)-Catalyzed P2P's
« on: February 12, 2002, 06:21:00 AM »
Go to Rhodium's site and read Mn(III)-Catalyzed Condensation of Benzene and Acetone at

https://www.thevespiary.org/rhodium/Rhodium/chemistry/p2p.manganese.html

You might just get a chubby. :)
  Here's my favorite part:

A mixture of Manganese(III)acetate dihydrate (13.4g, 50 mmol), benzene (150ml), acetone (150ml) and glacial acetic acid (250ml) was refluxed under an inert atmosphere (argon, helium or nitrogen) until the dark brown color of manganese(III)acetate changed to the pale pink of manganese(II)acetate (about 90 min). The reaction mixture was partitioned between 400ml ether and 250ml water. The ether layer was separated and washed with 250ml water and with 2x250ml 5% Na2CO3 to remove any remaining acetic acid. The ether was then dried over anhydrous Na2SO4 (or MgSO4), the solvent evaporated and the residue fractionately distilled to recover unreacted benzene, and to give phenyl-2-propanone in 40% yield (1.34g) based on the reacted manganese(III)acetate, which is the limiting reagent in this reaction.

If anhydrous Manganese(III)acetate is used, 50 mmol corresponds to 10.1g instead of the 13.4g of the dihydrate. When solid aromatics was used as substrates, the amounts used were reduced to facilitate the work-up process. In the case of 1,4-dimethoxybenzene, 100g (720 mmol) was used instead. Of course any unreacted starting material is recovered by distillation after the reaction and re-used in another run.


  My question: Has this procedure been tried on 3,4-methylenedioxybenzene? Would the reaction be too harsh for this delicate compound? If this were possible, I know alot of bees that would immediately stop dicking with sassy oil. Peace! 8)

  Love my country. Fear my government.

Rhodium

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Re: Mn(III)-Catalyzed P2P's
« Reply #1 on: February 12, 2002, 08:23:00 AM »
You will get an isomer mixture if methylenedioxybenzene is used, both 2,3-MDP2P and 3,4-MDP2P will form. You need to use a symmetrical arene to get only one product, such as benzene or 1,4-dimethoxybenzene.

Acme

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Re: Mn(III)-Catalyzed P2P's
« Reply #2 on: February 12, 2002, 08:50:00 AM »
It would seem that 1,4-dimethoxybenzene would lead to precursors for DOB, DOC, & DOI.  :)

Rhodium

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Re: Mn(III)-Catalyzed P2P's
« Reply #3 on: February 12, 2002, 08:57:00 AM »
1,4-dimethoxybenzene would lead to 1,4-dimethoxy-P2P, which can be reductuively aminated to form 2,5-DMA, a precursor for DOB, DOC, DOI etc. Sorry, no 2C-H here.

Acme

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Re: Mn(III)-Catalyzed P2P's
« Reply #4 on: February 12, 2002, 09:06:00 AM »
You posted that as I was editing; godamn, you are on the fucking ball man.

Bwiti

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Re: Mn(III)-Catalyzed P2P's
« Reply #5 on: February 12, 2002, 10:24:00 AM »
Thanks! 8)

  Love my country. Fear my government.