Acetic Acid → HCID 12795037, compound

HRID 638310Notes

Reaction equation

O.[BH4-].[Na+].[C:4]([O:7][CH2:8][CH2:9][N:10]1[CH:14]=[C:13]([Br:15])[CH:12]=[C:11]1[C:16](=[O:22])[C:17]([O:19][CH2:20][CH3:21])=[O:18])(=[O:6])[CH3:5].C(O)(=O)C>CO>[C:4]([O:7][CH2:8][CH2:9][N:10]1[CH:14]=[C:13]([Br:15])[CH:12]=[C:11]1[CH:16]([OH:22])[C:17]([O:19][CH2:20][CH3:21])=[O:18])(=[O:6])[CH3:5]

Participants

Conditions

Temperature: -50 °C

Procedure

Methanol (100 ml) containing 2.5 ml water is cooled to -50° C. and 3.07 g of sodium borohydride (81.2 mmole) is added with stirring. After 5 minutes, ethyl 1-(2-acetoxyethyl)-4-bromopyrrole-2-glyoxalate (8.9 g -26.7 mmole) is dissolved in 40 ml methanol and added at a rate such that the reaction temperature does not exceed -40° C. After 1 hour at this temperature, 50% aqueous acetic acid is added until the solution is weakly acidic. The methanol is then removed in vacuo, 100 ml ethyl acetate is added to the residue, and the organic phase is washed well with saturated salt solution and then dried over sodium sulfate. The solvent is removed in vacuo and the residue is immediately crystallized, at low temperature (dry ice-acetone bath), from ether. The ethyl 1-(2-acetoxyethyl)-4-bromopyrrole-2-glycolate thus obtained (6.0 g, 67%) exhibits a m.p. of 59° C. but is unstable and is be stored in an evacuated vessel at -10° C.

Workup

additionadded at a rate such that the reaction temperature
customdoes not exceed -40° C
customThe methanol is then removed in vacuo, 100 ml ethyl acetate
additionis added to the residue
washthe organic phase is washed well with saturated salt solution
dry with materialdried over sodium sulfate
customThe solvent is removed in vacuo
customthe residue is immediately crystallized, at low temperature (dry ice-acetone bath), from ether

Sources & evidence

ORD record: ord-5967890fffa64e67b03dd4d478cf6d28
Source dataset: uspto-grants-1985_12
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04560699

Reaction notes

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