07-03-04 08:47
No 517136
Ran a MM Nitro amination exactly as the page says. Have done quite a few reactions before and they have all been fine with the exception of 16 g being the normal yield (low compared to other bees). However, this time the reaction failed to reflux at all. The flask was hot but there was no reflux whatsoever, even when the drip was made fast. Should I bother working it up or just try again? anyone have any idea why this could happen? Reagents were all the same as previous reactions.
The working man is a sucker
(Hive Bee)
07-03-04 15:05
No 517158
Likely:
1) Not enough time left for the Al to amalgamate.
2) Not enough, or bad, Mercuric Chloride.
3) Wrong type of Al.
Less Likely:
4) Too much / too little water. If there is too little water in SWIM's experience the flask will clog up with Al(somethingorother). It's in the F* Search Engine. Too much water I don't think would make a difference.
5) Some contaminant in your reaction, maybe from improperly cleaned glassware.
If the vast majority of the Al didn't get used up, then the reaction is most likely close to a 100% failure. There may be a few percent of the expected yield still in there.
If you extract the reaction as it is now with Xylene/Toulene or other NP you may end up with a YELLOW tinged solution. This should/may be your MDP2P mixed with whatever other crap formed in the reaction. I've found if the extracts are yellow (the NP extracts I'm talking about) the reaction was usually a dismal failure.
I'm no expert but am quite experienced with this reaction.