反应详情

To a solution of 7-chloro-5-(4-chloro-phenyl)-pyrazolo[1,5-a]pyrimidine (1.0 g, 3.0 mmol), tetrakis(triphenylphosphin)palladium (0.35 g, 0.3 mmol) in THF (5 mL) was added at 20° C. 0.4 M ethylzinc chloride/THF solution (30 mL, 12 mmol; freshly prepared by stirring a mixture of 6 mL of 2 M ethylmagnesium chloride/THF and 24 mL of 0.5 M zinc chloride/THF for 1 h at 0° C. followed by 1 h at 20° C.) and the mixture was refluxed in an atmosphere of argon for 2 h. After the slow addition at 0° C. of sat. aqueous ammonium chloride solution (8 mL), the mixture was partitioned between ethyl acetate and 10% sodium chloride solution. The organic layer was evaporated in vacuo and the residue chromatographed on silica gel using ethyl acetate/cyclo-hexane (1:4 v/v) as eluent to give ethyl 5-(4-chloro-phenyl)-7-ethyl-pyrazolo[1,5-a]pyrimidine-3-carboxylic acid (0.53 g, 54%). This material was saponified using in an analogous manner the procedure described in example C.22, step d), to give the title compound. White solid; MS (ISN) 330.1 [(M−H)−]; mp 227° C.

1. customfreshly prepared
2. temperature) and the mixture was refluxed in an atmosphere of argon for 2 h
3. customthe mixture was partitioned between ethyl acetate and 10% sodium chloride solution
4. customThe organic layer was evaporated in vacuo
5. customthe residue chromatographed on silica gel