benzodioxole
Hello all, i am minding making some 3,4methylendioxypropiophenone or 3,4methylendioxyvalerophenone, my idea is a Fc aklylation with weak lewis acid
such as elemental iodine, i was worrying will this reaction work :
EXAMPLE lB
Second (and Preferred) Route to the Intermediate Ketone
A stirred mixture of 39 g methylenedioxybenzene, 48 g propionic anhydride and 1.54 g elemental iodine was held at reflux temperature with a heating
mantle for 3.5 h. The crude reaction mixture was freed of all volatiles that could be removed at 65"C, at the water pump, yielding 42 g of a heavy
black oil. The distillate smelled strongly of propionic acid. (Attempts to purify or decolorize this thick crude product by acid, base, or bisulfite
washing, were not successful.) The crude product was distilled at 0.1 mm/Hg. At 600C a sizable quantity of clear colorless liquid distilled over (the
temperature was maintained until the distillation was complete and the distillate was flamed into the traps).
Between 100-125 C a pale brown fraction distilled over, weighing 28 g. This was dissolved in 200 mL methylene chloride and decolorized by washing with
2x600 mli water, each portion containing 1 g sodium bisulfite. Removal of the organic solvent under vacuum gave 27.1 g of a pale brown residue which
was again distilled at 0.2 mm/Hg to give a fraction boiling at 90-1150C that was essentially white. This, on cooling, crystallized to give
3,4methylenedioxypropiophenone as a mass of off-white solids, weighing 24.46 g. Analysis by GC-MS showed a single sharp peak (about 97% purity) with a
spectrum identical to the product from the Grignard reaction above. A reference sample without color was obtained by grinding a little of the
distillate under a third its weight of cold methanol, followed by filtration.This sample had no detectable impurities by GC-MS.
I dont understant why they needed such a high temperature like 600C and Vacum to destill the reaction mixture, can i skip all these destilations and
extract the propiophenone with any solvent ? Also if i use valeric acid instead of propionic, will it give the coresponding valerophenone ?
[Edited on 11-11-2018 by dextro88]
[Edited on 11-11-2018 by dextro88]
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