Metronidazole → HCID 11105771, compound

Temperature

-50 °C

To 160 ml of CH2Cl2 was added dropwise 2 ml (22 mmol) of oxalyl chloride under nitrogen gas. The solution was cooled to −50° C. and 17 ml (240 mmol) of Me2SO was added dropwise to the stirred solution. About 20 min later, 3.42 g (20 mmol) of metronidazole [1-(2-hydroxyethyl)-2-methyl-5-nitroimidazole] dissolved in 15 ml of Me2SO was added. After 20 min of additional stirring, 33 ml (240 mmol) of triethylamine was added. The reaction mixture was stirred for another 10 min and then allowed to warm to room temperature. The mixture was diluted with 400 ml of ethyl acetate and washed 4 times with water, first with 100 ml and then 3 times with 50 ml. The 250 ml water volume was extracted 3 times with 250 ml of ethyl acetate and the ethyl acetate was added to the CH2Cl2. The mixture was washed with 100 ml of saturated NaCl solution, dried over anhydrous MgSO4, filtered, and concentrated to dryness in a rotary evaporator. The resulting crude residue was purified by flash silica gel chromatography to give the pure desired aldehyde (2-methyl-5-nitroimidazol-1-yl-acetaldehyde).

1. addition17 ml (240 mmol) of Me2SO was added dropwise to the stirred solution
2. additionwas added
3. temperatureto warm to room temperature
4. washwashed 4 times with water
5. extractionThe 250 ml water volume was extracted 3 times with 250 ml of ethyl acetate
6. additionthe ethyl acetate was added to the CH2Cl2
7. washThe mixture was washed with 100 ml of saturated NaCl solution
8. dry with materialdried over anhydrous MgSO4
9. filtrationfiltered
10. concentrationconcentrated to dryness in a rotary evaporator
11. customThe resulting crude residue was purified by flash silica gel chromatography

ORD record

ord-72d501d7082a40a78c40383420567991

Source dataset

uspto-grants-2001_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06255495B1