Bromine → Methyl 1-methyl-4-(thiocyanato)-1H-pyrrole-2-carboxylate

HRID 1388924Notes

Reaction equation

HRID 1388924 reaction equation
[S-:1][C:2]#[N:3].[K+].BrBr.[CH3:7][O:8][C:9]([C:11]1[N:12]([CH3:16])[CH:13]=[CH:14][CH:15]=1)=[O:10]>CO>[C:2]([S:1][C:14]1[CH:15]=[C:11]([C:9]([O:8][CH3:7])=[O:10])[N:12]([CH3:16])[CH:13]=1)#[N:3]

Participants

5

Reactant 3

HCID 24408BromineHCID 142178Methyl 1-methylpyrrole-2-carboxylateHCID 516872Potassium thiocyanate

Product 1

HCID 20469121Methyl 1-methyl-4-(thiocyanato)-1H-pyrrole-2-carboxylateYield 47.6%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent3×

Procedure

Potassium thiocyanate (6.44 g, 66 mmol) is suspended in 18 ml of methanol and cooled to -78° under nitrogen. A solution of 1.75 ml of bromine (33 mmol) in 10 ml methanol is added dropwise. The resulting light yellow suspension is stirred for an additional 5 minutes at -78° before 4.17 g (30 mmole) of 2-methoxycarbonyl-1-methylpyrrole in 5 ml methanol is added all at once. After stirring and gradual warming to room temperature, the reaction mixture is poured into 250 ml of ice water, stirred vigorously and filtered. The solid is washed with water, dissolved in methylene chloride, dried over anhydrous sodium sulfate, and concentrated in vacuo to give a white solid which after recrystallization from hexane-ethyl acetate gives 2.8 g of pure 4-cyanothio-2-methoxycarbonyl-1-methylpyrrole.

Workup

  1. temperaturecooled to -78° under nitrogen
  2. additionis added all at once
  3. stirringstirred vigorously
  4. filtrationfiltered
  5. washThe solid is washed with water
  6. dissolutiondissolved in methylene chloride
  7. dry with materialdried over anhydrous sodium sulfate
  8. concentrationconcentrated in vacuo
  9. customto give a white solid which
  10. customafter recrystallization from hexane-ethyl acetate

Sources & evidence

ORD record
ord-829ef05fe9284b499a2af129ac04f5e0
Source dataset
uspto-grants-1984_02
Patent number
US04434175

Reaction notes

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