3-indolyl-beta-methyl-beta-methylethylene

[Xicori]

High Bees!

Swim tried today the Henry condensation of Indole-3-carbaldehyde with Nitroethane.

It was done as follows:

15g Indole-3-COH were placed into a 250ml RBF together with 15ml Nitroethane, 7g of Ammonium Acetate and 70ml of Glacial Acetic Acid. The Mixture was hold at reflux for ~ 2 hours. During this time 20ml of Acetic Anhydride were added.

The colour went from yellow over a dark red to a nearly black solution. After the mixture had cooled down it was poured onto 200ml of ice water. A solid formed, and it was buchnered. -> yellow/brown & amorph

This was recrystallized from ~200ml of 96% EtOH to form  brown/yellowish crystals (still drying, so no weight available). The mother liquour has a deep red colour...to this was added water and crystals foarmed again....

So now my question... is the solid that crystallized out of the EtOH my nitropropene? what should it look like?

many thanks,
xicori

[Xicori]

the brown/yellowish solid obtained from recrystallisation is now dry, it weights 8,7g.

...the melting points of the desired product and indole-3-carbaldehyde are very close together, so indetification is very difficult...

is there any test to confirm the identity of the nitropropene?
many thanks,
x

[hest]

1: Make an TLC !
(iff you dont have TLC plate's paperchromatography is also ok (coffefilters ect)
2: The aldehyde will give a nice yellow spot with 2,4-dinitrophenylhydrazin.

[Lilienthal]

The nitropropene color should be yellow - as always.

[Rhodium]

Naah... In this case I'd say more towards the orange part of the spectrum...