Bromine → Ethyl 1-(2-acetoxyethyl)-4-bromopyrrole-2-glyoxalate

HRID 67113Notes

Reaction equation

[Br:1]Br.[C:3]([O:6][CH2:7][CH2:8][N:9]1[CH:13]=[CH:12][CH:11]=[C:10]1[C:14](=[O:20])[C:15]([O:17][CH2:18][CH3:19])=[O:16])(=[O:5])[CH3:4].CCCCCC.C(OCC)(=O)C>ClCCl>[C:3]([O:6][CH2:7][CH2:8][N:9]1[CH:13]=[C:12]([Br:1])[CH:11]=[C:10]1[C:14](=[O:20])[C:15]([O:17][CH2:18][CH3:19])=[O:16])(=[O:5])[CH3:4]

Participants

Conditions

Temperature: -75 °C

Procedure

Three ml (58.3 mmole) of bromine is added in a dropwise manner to a stirred solution of 14.77 g (58.3 mmole) of ethyl 1-(2-acetoxyethyl)pyrrole-2-glyoxalate in 200 ml anhydrous dichloromethane, cooled to -75° C. After the addition, the reaction is left at -75° C. for 2.5 hours and then the temperature is allowed to increase to room temperature. The solvent is removed in vacuo, dichloromethane is added to the residue and the solution is washed successively with water, 10% sodium bicarbonate solution and water. The organic phase is dried over sodium sulfate, and the solvent is removed in vacuo. The crude product thus obtained (18.3 g) is subjected to column chromatography on Florisil (1 Kg) using hexane-ethyl acetate (9:1) as the eluting solvent. There is thus obtained upon removal of the solvent, 10.9 g (56%) of ethyl 1-(2-acetoxyethyl)-4-bromopyrrole-2-glyoxalate as an oil having the following physical constants:

Workup

additionAfter the addition
temperatureto increase to room temperature
customThe solvent is removed in vacuo, dichloromethane
additionis added to the residue
washthe solution is washed successively with water, 10% sodium bicarbonate solution and water
dry with materialThe organic phase is dried over sodium sulfate
customthe solvent is removed in vacuo
customThe crude product thus obtained (18.3 g)

Sources & evidence

ORD record: ord-00fdc22f138741beb6add2da08e5184d
Source dataset: uspto-grants-1982_08
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04344943

Reaction notes

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