Dimethylformamide → 2-Amino-4-ethoxy-5-formylthiophene-3-carbonitrile

HRID 1591293Notes

Reaction equation

HRID 1591293 reaction equation
[NH2:1][C:2]1[S:3][CH:4]=[C:5]([O:9][CH2:10][CH3:11])[C:6]=1[C:7]#[N:8].[OH-].[Na+].CN(C)[CH:16]=[O:17]>P(Cl)(Cl)(Cl)=O>[NH2:1][C:2]1[S:3][C:4]([CH:16]=[O:17])=[C:5]([O:9][CH2:10][CH3:11])[C:6]=1[C:7]#[N:8]

Participants

5

Reactant 3

HCID 6228DimethylformamideHCID 14798Sodium HydroxideHCID 137423802-Amino-4-ethoxythiophene-3-carbonitrile

Product 1

HCID 189632142-Amino-4-ethoxy-5-formylthiophene-3-carbonitrile

Reagents, catalysts & solvents 1

HCID 24813Phosphorus oxychlorideSolvent

Procedure

168 parts of 2-amino-3-cyano-4-ethoxythiophene (Example 1) are dissolved in 500 parts of dimethylformamide, and 200 parts of phosphoryl trichloride are added dropwise to the stirred solution. The reaction is exothermic, and the rate of dropwise addition is adjusted so that the temperature of the reaction mixture does not exceed 50° C. Stirring is continued for 4 hours at 50° C., 50 parts of ice are added, and the mixture is stirred until a clear solution has formed. This solution is run into 2000 parts of 12.5% strength sodium hydroxide solution and the temperature is kept at 20°-30° C. Stirring is continued for 8 hours at room temperature, after which the product is filtered off under suction, washed with water and dried. 185 parts of 2-amino-3-cyano-4-ethoxy-5-formylthiophene are obtained. A sample recrystallized from pentanol melts at 245°-246° C. and has the following analytical values:

Workup

  1. additionare added dropwise to the stirred solution
  2. additionthe rate of dropwise addition
  3. customdoes not exceed 50° C
  4. addition50 parts of ice are added
  5. stirringthe mixture is stirred until a clear solution
  6. customhas formed
  7. customis kept at 20°-30° C
  8. stirringStirring
  9. waitis continued for 8 hours at room temperature
  10. filtrationafter which the product is filtered off under suction
  11. washwashed with water
  12. customdried

Sources & evidence

ORD record
ord-094d0e84c06c470da4ec7a13d279ac87
Source dataset
uspto-grants-1993_04
Patent number
US05206375

Reaction notes

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