N,N-Dimethylethylenediamine → HCID 71008951, compound

Temperature

25 °C

A solution of N,N-dimethylethylenediamine (1.8 ml, 16.76 mmol) in toluene (30 ml) was treated dropwise at 0° C. under an argon atmosphere with trimethylaluminum (2M in toluene, 22.86 ml, 45.7 mmol). The reaction mixture was stirred at 25° C. for 1 hour before adding 1-(3-bromo-phenyl)-1H-pyrazole-4-carboxylic acid ethyl ester (3.8 g, 12.8 mmol) (CAS 784142-89-8; WO2004092140). The resulting mixture was heated to reflux for 12 hours. For the workup, the mixture was cooled to 25° C., quenched with hydrochloric acid (1N) and extracted with ethyl acetate (3×100 ml). The combined organic layers were washed with brine (50 ml), dried over sodium sulphate and evaporated at reduced pressure. The crude material thus obtained was purified by column chromatography on silica gel using a 9:1-mixture of hexane and ethyl acetate as the eluent to give the 1-[1-(3-bromo-phenyl)-1H-pyrazol-4-yl]ethanone (2.4 g, 83.5%) as an off-white solid. MS (ISP): m/z=310 [M+CH3CN]+.

1. temperatureThe resulting mixture was heated
2. temperatureto reflux for 12 hours
3. temperatureFor the workup, the mixture was cooled to 25° C.
4. customquenched with hydrochloric acid (1N)
5. extractionextracted with ethyl acetate (3×100 ml)
6. washThe combined organic layers were washed with brine (50 ml)
7. dry with materialdried over sodium sulphate
8. customevaporated at reduced pressure
9. customThe crude material thus obtained
10. customwas purified by column chromatography on silica gel using a 9

ORD record

ord-48d5f58596bc4e56bda69653750c4923

Source dataset

uspto-grants-2014_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08785436B2