methyl 3-bromo-4-oxopentanoate synthesis

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Yield:-

Reaction Conditions:

with bromine in methanol; for 0.416667 h;Heating / reflux;

Steps:

In one embodiment of the present invention, according to Fig. 1, 29.6 g levulinic acid (0.25 mole 98%), dissolved EPO in 600 ml methanol (analytical 99.8%), was heated up to reflux. 40 g bromine (12.86 ml) was added dropwise, during stirring, to the refluxing levulinic acid solution in the following manner. The first three drops needed approximately 2 minutes initiation time to react (complete disappearance of the bromine) . Then the addition was adjusted at the rate of disappearance of the bromine. The stirring continued for further two minutes, after the total amount of bromine had been added (approximately 25 minutes), until the solution was colourless.The solvent was then distilled off by reduced pressure (or evaporation) , until the volume of the reaction mixture reached 75 ml. A volume of approximately 80 ml ice cold water was added to the solution with stirring. Thereafter, a concentrated NaHCO₃ solution was carfully added until the solution reached neutral .The product, which is an organic mixture that has a higher density than water, was extracted with 25 ml ethylacetate, and the lower layer (ethylacetate phase) was separated. The upper layer (water phase) was then extracted additionally two times with 40 ml ethylacetate. The combined organic layer (the three ethylacetate phases) was then drained (there was no need to dry the solution, since the moisture content is azotroped out together with the solvent during evaporation) , and the solvent evaporated under reduced pressure. The obtained product was a mixture of alkyl-3-bromolevulinate and alkyl-5-bromolevulinate. Said mixture (50.5 g (96.6%) of a colorless oily substance) was dry enough to be used without further treatment in the step of synthesis, according to Fig. 1.

References:

WO2006/48236,2006,A1 Location in patent:Page/Page column 5-6