Formaldehyde → 5-Amino-1-(2,6-dichloro-4-trifluoromethylphenyl)-3-(2,5-dihydro-2-methyl-1,2,4-oxadiazol-3-yl)-4-trifluoromethylsulfinylpyrazole

Temperature

50 °C

5-Amino-1-(2,6-dichloro-4-trifluoromethylphenyl)-3-(N-hydroxy-N-methylamidino)-4-trifluoromethylsulfinylpyrazole(1.00 g, 2.07 mmol) was dissolved in 10 ml of acetonitrile, and then aqueous 37% formaldehyde solution 840 mg (10.3 mmol) and 5 drops of acetic acid were added. After the mixture was stirred at 50° C. for 5 hours, aqueous 37% formaldehyde solution 840 mg (10.3 mmol) and, 5 drops of acetic acid were further added, followed by stirring at 50° C. for 5 hours. The reaction mixture was concentrated in vacuo and to the residual oil was added ethyl acetate, and then washed twice with an aqueous saturated sodium hydrogencarbonate solution, once with an aqueous saturated sodium chloride solution. After drying over anhydrous magnesium sulfate, the solvent was distilled off. The resulting concentrated residue was purified by silica gel column chromatography [eluent: mixed solvent of ethyl acetate and n-hexane (volume ratio=1:2)] to obtain 260 mg (0.52 mmol) of the title compound as a colorless crystal. Yield 25%.

1. stirringby stirring at 50° C. for 5 hours
2. concentrationThe reaction mixture was concentrated in vacuo and to the residual oil
3. additionwas added ethyl acetate
4. washwashed twice with an aqueous saturated sodium hydrogencarbonate solution, once with an aqueous saturated sodium chloride solution
5. dry with materialAfter drying over anhydrous magnesium sulfate
6. distillationthe solvent was distilled off
7. customThe resulting concentrated residue was purified by silica gel column chromatography [eluent: mixed solvent of ethyl acetate and n-hexane (volume ratio=1:2)]

ORD record

ord-ea7655438afb498ead8192fda7830f09

Source dataset

uspto-grants-2001_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06316477B1