Synthesis of Piperonal from 3,4-dihydroxybenzaldehyde (small scale)

[WillD]

Reaction scheme:

Synthesis:
1. A solution of 3,4-dihydroxybenzaldehyde (5 g, 0.011 mol) in DMF (150 ml) was added dropwise to a suspension of CH2Br2 (31,4 ml,16.7 mol) and K2CO3 (10g, 0.0362 mol) in DMF (30 ml).
2. The mixture was stirred and heated at reflux for 24 h, then cooled and filtered.
3. The filtrate was concentrated, diluted with water, and extracted with ethyl acetate (3x100 mL).
4. The filter cake was with ethyl acetate (25 ml).
5. The organic layer was washed with 10% NaOH (25 ml), water (25 ml), dried (Na2SO4), and evaporated to afford 2 g (38%) of a yellow oil.

 

[Uliley]

OMG I've been looking for this for what seems like for ever thx!

Can you replace K2CO3 with Na2CO3? And the CH3Br2 with DCM like in the MDbenzene synthesis?
And "heated at reflux" to which temp?

Oh! And I'm pretty sure that the ethyl acetate can be replaced with ether.

 

[UWe9o12jkied91d]

Reflux = boiling. So naturally your mixture will be capped at the temp of your lowest bp volatile.Providing more heat will not increase the temp of the mixture in reflux, it will just make it go faster and eventually boil over if you let it.

 

[simple simon]

Can dichloromethane substitute for dibromomethane?

 

[megurine]

Why use so little 3,4-dihydroxybenzaldehyde, can I use more?