SYNTHESIS OF 5-METHYL-2-PROPIONYLFURAN Russian patent published in 2006 - IPC C07D307/46 

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to a method for synthesis of 5-methyl-2-propyonylfuran that is an intermediate product of the broadly known antioxidant - 2-ethyl-5-methyl-3-hydroxypyridine and its salts used in technique, agriculture and medicine (preparations "Emoxipine", "Mexidol" and others). Method of synthesis involves the acylation process that is carried out by the simultaneous mixing reagents and polyphosphoric acid as a catalyst under adiabatic conditions in the following mole ratio of components 2-methylfuran : propionic anhydride : polyphosphoric acid = 1:(1.02-1.06):(0.025-0.04), respectively; during the process the temperature increases spontaneously to the optimal value 130-140°C and at this temperature the heat exposition is carried out for 30-60 min. Then the reaction mass is cooled and pure product is isolated by neutralization of propionic acid formed as result of the reaction with an aqueous solution of alkaline agent not evolving gas in the neutralization reaction. The proposed method provides synthesis of 5-methyl-2-propionylfuran with the yield above 93% with sufficient purity (T²⁰ = 1.5080, the content is above 96%) with minimal energy consumption for the total period of the process 2-2.5 h and in the absence of toxic waste gases and not utilized waste.

EFFECT: improved method of synthesis.

4 cl, 24 ex