methyl 3-chloro-5-formyl-1H-pyrrole-2-carboxylate → methyl 3-chloro-5-ethenyl-1H-pyrrole-2-carboxylate

HRID 1874973Notes

Reaction equation

HRID 1874973 reaction equation
[CH2:1]([Li])CCC.[Cl:6][C:7]1[CH:11]=[C:10]([CH:12]=O)[NH:9][C:8]=1[C:14]([O:16][CH3:17])=[O:15]>[Br-].C[P+](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1.C1COCC1>[Cl:6][C:7]1[CH:11]=[C:10]([CH:12]=[CH2:1])[NH:9][C:8]=1[C:14]([O:16][CH3:17])=[O:15]

Participants

5

Reactant 2

HCID 86644900methyl 3-chloro-5-formyl-1H-pyrrole-2-carboxylateHCID 178418339Butyllithium

Product 1

HCID 68485391methyl 3-chloro-5-ethenyl-1H-pyrrole-2-carboxylateYield 40.7%

Reagents, catalysts & solvents 2

HCID 74505Methyltriphenyliphosphonium bromideCatalystHCID 8028TetrahydrofuranSolvent2×

Procedure

A suspension of methyl(triphenyl)phosphonium bromide (3.97 g, 11.1 mmol) in 20 mL of THF was cooled to −78° C. n-Butyllithium (1.6 M in Hexanes, 6.93 mL, 11.1 mmol) was added and the resulting yellow solution stirred for 20 minutes. A THF solution of methyl 3-chloro-5-formyl-1H-pyrrole-2-carboxylate (0.522 g, 2.78 mmol) was added and the reaction was warmed to RT. The reaction mixture was partitioned between EtOAc and water and the layers were separated. The organic layer was dried over MgSO4, filtered and the solvent evaporated. Purification was accomplished by silica gel column chromatography (EtOAc/hexanes) to afford the title compound (0.210 g, 40%) as a white solid. 1H NMR (400 MHz, Acetone-d6) δ ppm 11.05 (br. s., 1H), 6.62 (dd, 1H), 6.42 (d, 1H), 5.83 (d, 1H), 5.25 (d, 1H), 3.79 (s, 3H). LCMS: m/z=184.6 (M−1).

Workup

  1. additionwas added
  2. customThe reaction mixture was partitioned between EtOAc and water
  3. customthe layers were separated
  4. dry with materialThe organic layer was dried over MgSO4
  5. filtrationfiltered
  6. customthe solvent evaporated
  7. customPurification

Sources & evidence

ORD record
ord-8b604672ef9749a988ca3d03898cc48b
Source dataset
uspto-grants-2012_11
Patent number
US08304419B2

Reaction notes

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