Hi!
Bariums method is now tested and has proved very succesfull:
The following was added in succession to a 50 mL RBF, placed in a waterbath:
5,5 g (33 mmole, MW=166 g/mole) 2,5-dimethoxybenzaldehyde
2,7 g (35 mmole, MW=75 g/mole) nitroethane
½ mL (6,5 mmole, MW=31 g/mole) 40% aqueus methylamine
Finally methanol was added to take everything into the solution. It took roughly 10 mL's with swirling.
The color of the solution was slightly yellow tinted. To avoid the methanol escaping, a vigreux column was used as an air cooled reflux condensor. This worked just fine because of the low temperatures. It was warmed up to 65 degrees on the waterbath and held there for about one hour. At this point the reaction mixture was nicely canary yellow. When the reaction was done(60 mins), ½ mL 85% formic acid was added(no GAA available).
The mixture was put into the fridge and cooled. After 30 mins, the whole lot had crystallized into a canary yellow mess. It was filtered on suction, but only very few crystals remained. They where washed with IPA, but it was quite soluble, so a lot of product got lost here. After a few days, the solvent was stripped on a hotplate, and the remaining oil was dissolved in chloroform and washed two times with water, which was back extracted with chloroform a final time. The collected chloroform mixtures was evaporated and a dark yellow/red oil remained. This was cooled down in a fridge, but alas no crystals formed. After scraping for 10 secs with a glass rod, the whole mess crystallized into beatifull yellow crystals.
The final yeild of 2,5-dimethoxynitropropene was 4,0 grammes(18 mmol, MW=223 g/mole) which is 55% yeild calculated from the benzaldehyde. A lot where lost because the solvent was not stripped straight away and wash with water, but the yeild is still very nice. Next time i suspect the yeild to go even higher!
Way to go Barium!
Now lets see what some LAH can do to this bugger molecule
Regards
Bandil