What is 4-Chloromethyl-5-methyl-1,3-dioxole-2-one?

The 4-chloromethyl-5-methyl-1,3-dioxole-2-one(CAS: 80841-78-7) is a compound very useful for preparing prodrugs[1-2]. But how is this compound itself synthesized? Here, we introduced an invention (CN104230878A) for production of 4-chloromethyl-5-methyl-1,3-dioxole-2-one.

The invention discloses a preparation method of 4-chloromethyl-5-methyl-1,3-dioxole-2-one. The preparation method comprises the following specific steps: in the presence of solid alkali, carrying out hydroxyl protection on 3-hydroxy-2-butanone, using thionyl chloride to chlorinate the substance, under the action of an acidic condition, reducing the hydroxyl, conducting ester exchange and cyclization with dimethyl carbonate, and at last obtaining the target product 4-chloromethyl-5-methyl-1,3-dioxole-2-one. The preparation method disclosed by the invention is simple in technology, easy to get the raw materials, mild in reaction conditions, and high in yield and purity of the product. The adopted catalyst is free of corrosion on the equipment, simple and convenient to prepare, and capable of being recycled, so that the preparation method is low in process cost, easy to realize industrial implementation, and is good in economic benefits.

The present invention is to solve the technical problem of providing a cheap and easily available raw materials and environmental protection, safe production, the reaction yield, low cost, easy to handle and less waste of 4-chloro-5-methyl - the method of preparing 1,3 dioxol-2-one. In order to solve the above problems, the present invention adopts the technical solution is: 4_-chloro-5-methyl-1,3-dioxol-prepared 2-one, comprising the steps of:

in a reactor with a reaction distillation apparatus, was added 3-hydroxy-2-butanone, triphenylchloromethane, solid base and an organic solvent heated at 15~30 ° C under nitrogen the reaction mixture was reacted 3~6h, sync-product hydrogen chloride gas was distilled and collected; the molar ratio of 3-hydroxy-2-butanone and triphenylmethyl chloride is 1: ~ 1.5;

maintained at this temperature, thionyl chloride was added to keep the reaction 3~5h, continue to steam-product hydrogen chloride; After completion of the reaction, the reaction solution was filtered, washed with water, the organic phase was separated and dried, to obtain a reaction liquid A ; molar ratio of said 3-hydroxy-2-butanone, and thionyl chloride is 1: ~ 1.5;

The reaction 2~5h NaHSO4 was added at room temperature to the reaction solution A; The reaction solution was filtered, washed with water after the completion of the reaction, the organic phase was separated and dried to obtain a reaction solution B; said 3-hydroxy-2 - molar ratio of butanone and NaHSO4 is 1: 1-1.4;

was added to the reaction liquid B of dimethyl carbonate was heated to reflux under acidic conditions the solid 3~7h, and finally cooled to room temperature and filtered to obtain a filtrate; acetoin and the dimethyl carbonate ester molar ratio of 1: 1~2.0;

and the filtrate solvent was evaporated; to give product 4-chloro-5-methyl-1,3-dioxol dilute Li ~ 2 ~ crude product.

Advantageously, after step (5), further comprising the step of:

Takes chloromethyl-5-methyl-1,3-dioxol-one The crude product was added _2_ recrystallization solvent, the temperature was lowered stirred -5~0 ° C, crystallization time 5~10h, washed with a solvent to give a white suspension body recrystallized, filtered off with suction, the filter cake at a temperature of 90 ° C, and dried under a vacuum degree of -133kpa 2~5h, purified to give 4-chloro _1,3- dioxin-5-methyl-2-pentene.

The present invention uses inexpensive raw materials, mild reaction conditions, high yields and purity, simple process, the solid catalyst can accelerate the reaction and shorten the reaction period. Non-corrosive, do not pollute the environment, low-temperature catalytic reaction, easy preparation, recyclable, so that the production cost is low, the advantages of easy industrial embodiment, with good economic [3].

References

[1] https://pubchem.ncbi.nlm.nih.gov/compound/4-_Chloromethyl_-5-methyl-1_3-dioxol-2-one#section=Molecular-Formula

[2] Ikeda, Shoji , et al. "A convenient and practical preparation of 4-chloromethyl-5-methyl-1,3-dioxol-2-one. " CHEMICAL & PHARMACEUTICAL BULLETIN 36.1(1988):394-397.

[3] https://patents.glgoo.top/patent/CN104230878A/en?q=4-Cloromethyl-5-methyl-1%2c3-dioxol-2-one&oq=4-Cloromethyl-5-methyl-1%2c3-dioxol-2-one