Introducción: MDP2P by 2-Nitropropene Alkylation of 1,3-Benzodioxole
MDP2P by 2-Nitropropene Alkylation of 1,3-Benzodioxole by Scooby Doo
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Procedure
To a 3-necked 500 ml flask under a nitrogen atmosphere was added 300 mls of dry DCM, 0.1 mole of 2-Nitropropene (8.7g) and 0.5 moles of 1,3-Benzodioxole (61g). The flask was then secured within a dewar flask sitting on top of a magnetic stirplate. Dry ice was added to the dewar flask which was filled with acetone until a temperature of approx -78º C was acquired. Once the internal flask temperature of -70ºC was reached, 0.1 mole (19g) of TiCl4 was dripped slowly into the stirred solution. The temp started to rise so the addition was controlled to keep the internal flask temp around -60°C to -70º C. The flask was then stirred for 30 mins at -70º C, by which time the precipitate which formed from the addition had dissipated. The dewar flask was removed and the stirring solution was allowed to warm up to room temperature, during which time the black solution will change viscosity and colour.
To hydrolyze the formed nitro-titanium complex, 100 mls of water was added to the solution which was then refluxed for 2 hours. During the reflux a brown gas (probably NO2) is evolved. The flask was cooled and vacuum filtered (cleans it up a lot) the water layer seperated and discarded. The organic layer was then washed with 3×200 mls of 10% NaOH and 1x200ml of a brine solution. It was then dried with magnesium sulfate, the DCM evaporated and resulting orangey/yellow oil vacuum distilled. The 1,3-Benzodioxole came over at 40-45ºC at 10 mbar then a fluoro yellow/green oil (MDP2P) started distilling at 135ºC at 3 mbar.
8g of MDP2P was collected, which is a 45% yield from 2-Nitropropene or 23.5% from 1,3-Benzodioxole (calculated from the 1,3-Benzodioxole that was not recovered during the vacuum distillation)./p>
Reference: Tet Lett 29(24), 2977-2978 (1988)
