Dimethylformamide → 5-(p-Chlorobenzoyl)-2-diazomethylcarbonyl-4-methylthio-1-methylpyrrole

HRID 1388928Notes

Reaction equation

HRID 1388928 reaction equation
[Cl:1][C:2]1[CH:20]=[CH:19][C:5]([C:6]([C:8]2[N:12]([CH3:13])[C:11]([C:14]([OH:16])=O)=[CH:10][C:9]=2[S:17][CH3:18])=[O:7])=[CH:4][CH:3]=1.C(Cl)(C(Cl)=O)=O.CN(C)C=O.[N+:32](=[CH2:34])=[N-:33]>C(Cl)Cl>[Cl:1][C:2]1[CH:3]=[CH:4][C:5]([C:6]([C:8]2[N:12]([CH3:13])[C:11]([C:14]([CH:34]=[N+:32]=[N-:33])=[O:16])=[CH:10][C:9]=2[S:17][CH3:18])=[O:7])=[CH:19][CH:20]=1

Participants

6

Reactant 4

HCID 6228DimethylformamideHCID 9550DiazomethaneHCID 65578Oxalyl chlorideHCID 204690825-(p-Chlorobenzoyl)-2-hydroxycarbonyl-4-methylthio-1-methylpyrrole

Product 1

HCID 538466435-(p-Chlorobenzoyl)-2-diazomethylcarbonyl-4-methylthio-1-methylpyrrole

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

To a solution of the crude 5-(p-chlorobenzoyl)-2-hydroxycarbonyl-4-methylthio-1-methylpyrrole in 3 ml of methylene chloride is added 100 μl of (COCl)2 followed by the addition of 0.5 μl of dimethylformamide (DMF). The resulting reaction mixture is stirred for about an hour and then concentrated to give a yellow solid. Subsequently freshly prepared diazomethane is added dropwise to a stirred solution of the yellow solid in 1 ml of methylene chloride at 0°. The reaction is allowed to warm up to room temperature over a period of one hour. After the excess amount of diazomethane is removed by bubbling nitrogen through the reaction mixture, the solvents are removed by evaporation under reduced pressure and a bright yellow solid is collected. This crude product, i.e., 5-(p-chlorobenzoyl)-2-diazomethylcarbonyl-4-methylthio-1-methylpyrrole, is used directly in the next step without further purification.

Workup

  1. customThe resulting reaction mixture
  2. concentrationconcentrated
  3. customto give a yellow solid
  4. customAfter the excess amount of diazomethane is removed
  5. customby bubbling nitrogen through the reaction mixture
  6. customthe solvents are removed by evaporation under reduced pressure
  7. customa bright yellow solid is collected
  8. customThis crude product, i.e., 5-(p-chlorobenzoyl)-2-diazomethylcarbonyl-4-methylthio-1-methylpyrrole, is used directly in the next step without further purification

Sources & evidence

ORD record
ord-90142828b06a435bb65a732e0f153a11
Source dataset
uspto-grants-1984_02
Patent number
US04434175

Reaction notes

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