methyl 2,2,2-trifluoroacetate

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a stirred solution of 3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-4-iodopyrazole (4.62 g) in tetrahydrofuran (100 ml) at -75° C. under an atmosphere of nitrogen was added, at such a rate that the temperature of the reaction mixture did not exceed -75° C., n-butyllithium (4.7 ml of a 2.5M solution in hexanes). A solution of methyl trifluoroacetate (1.93 ml) in tetrahydrofuran (5 ml) was then added at such a rate that the temperature of the reaction mixture did not exceed -75° C. Upon completion of the addition the mixture was allowed to warm to room temperature. Water (100 ml) was added and the mixture extracted twice with ethyl acetate (80 ml). The combined organic layers were dried (Na2SO4) and evaporated to give a brown gum which was purified by column chromatography on silica gel (250 g) eluted with dichloromethane. Combination and evaporation of suitable fractions gave the title compound as a pale yellow solid, m.p. 124-125° C. did not exceed -75° C. did not exceed -75° C Upon completion of the addition the mixture the mixture extracted twice with ethyl acetate (80 ml) The combined organic layers were dried (Na2SO4) evaporated to give a brown gum which was purified by column chromatography on silica gel (250 g) eluted with dichloromethane Combination and evaporation of suitable fractions

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 42.0 g (0.33 mol) of methyl trifluoroacetate, 26.6 g (0.33 mol) of -chloroethanol, and 150 mL of dimethylsulfoxide (DMSO) was stirred at 10°-20° while 15.8 g (0.33 mol) of 50% NaH in mineral oil was added portionwise. The resulting mixture was stirred at 20° for 2 h, at 25° for several days, and then poured into 1 L of water. The resulting aqueous layer was extracted with 100 mL of ether. The organic layers were combined, then washed twice with water, dried over CaSO4, and distilled to give 35.6 g (63% yield) of 2-methoxy-2-trifluoromethyl-1,3-dioxolane, b.p. 60°-65° at 3.3 kPa (25 mm), and a residue containing about 4.8 g (7% yield) of by-product -(2-chloroethoxy)-2-trifluoromethyl-1,3-dioxolane (estimated by GC). was added portionwise The resulting aqueous layer was extracted with 100 mL of ether washed twice with water dried over CaSO4 distilled