Phosgene → 1-Formyl-4-methylpiperazine

Phosgene (1.31 mL, 2.53 mmol, 1.93 M in toluene) was added dropwise to a cooled (0° C.) mixture of triethylamine (0.37 mL, 2.64 mmol) and 4,5-bis-(4-chloro-phenyl)-2-(2,4-dimethoxy phenyl)-4,5-dihydro-1H-imidazole (225 mg, 0.53 mmol, example 1) in THF (5 mL). The reaction mixture was stirred for 2.5 h and evaporated. The residue was kept under high vacuum for 30 min and was redissovled in methylene chloride (10 mL). The slurry was added dropwise to a solution of N-methylpiperazine (1.05 g, 10.48 mmol) in methylene chloride (5 mL). After 1 h, the reaction was worked up with aqueous sodium bicarbonate and extracted with methylene chloride. The organic extracts were washed with water and brine, and dried over sodium sulfate. Evaporation of the solvents and chromatography of the residue over silica gel using 1-4% methanol in methylene chloride gave 4,5-bis-(4-chloro-phenyl)-2-(2,4-dimethoxy-phenyl)-4,5-dihydro-imidazol-1-yl]-(4-methyl-piperazin-1-yl)-methanone. HR-MS (ES, m/z) calculated for C29H31N4O3Cl2[(M+H)+]553.1768, observed 553.1773.

1. temperaturea cooled
2. customevaporated
3. waitThe residue was kept under high vacuum for 30 min
4. waitAfter 1 h
5. extractionextracted with methylene chloride
6. washThe organic extracts were washed with water and brine
7. dry with materialdried over sodium sulfate
8. customEvaporation of the solvents and chromatography of the residue over silica gel using 1-4% methanol in methylene chloride

ORD record

ord-8a6a09986fc64139a780cf2403421e88

Source dataset

uspto-grants-2004_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06734302B2