Ethyl 4,4,4-trifluoroacetoacetate → HCID 178498903, compound

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Reaction Steps

A mixture of 11.5 g of methyl 5-aminopyrazole-4-carboxylate, 16 ml of ethyl ω,ω,ω-trifluoroacetoacetate and 150 g of polyphosphoric acid was heated to 100° while stirring for 16 hours. After cooling to 20°, cold water was added and the mixture was extracted with ethyl acetate. The organic phase was washed with 1N aqueous hydrochloric acid and aqueous saturated sodium chloride solution and then dried over Na2SO4. The solvent was evaporated in a vacuum and the residue was taken up in ether. The solid product was filtered off under suction and recrystallized from 2-propanol. There was obtained an isomer of the product, namely methyl 7-hydroxy-5-(trifluoromethyl)pyrazolo-[1,5-a]pyrimidine-3-carboxylate of m.p. 216°-217°. The product enriched in the mother liquors was crystallized from ethyl acetate. There was obtained methyl 5-hydroxy-7-(trifluoromethyl)pyrazolo[1,5-a]pyrimidine-3-carboxylate of m.p. 149°-150°.

Provenance & Evidence