Acetic Acid → HCID 20309098, compound

Participants

Reaction Steps

A mixture of 9.3 parts of 2-carbethoxycycloheptanone [prepared by the method of G. Stork, et al., J. Am. Chem. Soc., 85, 207 (1963)], 8.1 parts of 4-chloro-2-fluorophenyl hydrazine, 100 parts of toluene and 0.5 parts of acetic acid was refluxed for 4 hours until all water was evolved. The resulting solution was cooled to -50° and filtered to yield 12 parts of 2-(4-chloro-2-fluorophenyl)-1,4,5,6,7,8-hexahydrocycloheptapyrazol-3(2H)-one melting at 197°-201°. Four parts of the pyrazolone was mixed with 4.4 parts of phosphorous oxybromide and 2.2 parts of N,N-diethylaniline in 200 parts of xylene and the mixture refluxed for 3 hours. 0.5 Part of N,N-dimethyl formamide was added and the mixture refluxed for 1 hour. The mixture was poured over 100 parts of ice and the phases separated. The organic phase was evaporated under reduced pressure of 50 mm. Hg at 70° to a crude product. The product was dissolved in 100 parts of chloroform, washed with 100 parts of 10% aqueous sodium carbonate, dried with anhydrous magnesium sulfate and evaporated to an oil under reduced pressure of 500 mm. Hg at 40°. Purification by chromatography on alumina using 3% ether in hexane as the eluent gave 0.8 parts of 3-bromo-2-(4-chloro-2-fluorophenyl)-2,4,5,6,7,8-hexahydrocycloheptapyrazole melting at 59°-60°.

Provenance & Evidence