Author Topic: Canizzaro reduction of subst'd benzaldehydes  (Read 552 times)

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Antoncho

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Canizzaro reduction of subst'd benzaldehydes
« on: July 12, 2002, 06:31:00 PM »
For the ones who prefer reducing nitriles (hydrazine hydrate over Raney Ni gives excellent results - has it ever been posted?) to reducing nitrostyrenes. Convertion of a PhCHO to BzOH via Canizzaro rxn (then treated w/HCl and KCN) as described on Rh's site.



Patent GB627769




Antoncho

Tricky

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Nitriles reduction.
« Reply #1 on: August 22, 2002, 07:22:00 PM »
Hmmmm.
Last time I'm crazy about reduction of nitriles, cause I find a simple ways to 2C-substantions...
So, what do I know about nitriles???
After that I UTFSEd I found only one post I've like, this post, there Antoncho mentioned about reduction of nitriles over Raney nickel with great yield...
Antoncho, it seems noonebee observed you said... Let's try to improve it   ;)
So, what do I know about nitriles???

Triptamine synthesis (quoted from Khimicheskaja nauka i promyshlennostj, 1959,4, N2,281-282).
Nitrile reduction with Hydrazine hydrate over Raney-Nickel
Here mentioned, this method works with benzylcyanides too
To mixture of 0,016mol of 3-indolylacetonitrile, 0,5g of Raney-Nickel catalist and 50ml of ethanol, 48ml of hydrazine hydrate was added by small portions. After addition was completed, mixture was heated to 100C. Heating was continued until the NH3-isolation bring to a stop. Catalist was filtered off and ethanol was evaporated in vacuo.
Result - 2,4g of triptamine, yield is 95%.
Enjoy.

BTW, does somebee knows, will the Mannich rxn work with 2,5-DMBA (to produce 2,5-dimethoxy-4-N,N-dimethylaminomethylbenzaldehyde)??? 
Thanx.


There's a hole in our soul that we fill with dope
And we're feeling fine.

Rhodium

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No, the Mannich reaction only works with phenols.
« Reply #2 on: September 02, 2002, 12:03:00 PM »
No, the Mannich reaction only works with phenols.