Hydrochloric Acid → Ethyl [3-(2-chlorobenzoyl)-5-ethyl-2-thienyl]azochloroacetate

HRID 328611Notes

Reaction equation

HRID 328611 reaction equation
[NH2:1][C:2]1[S:3][C:4]([CH2:16][CH3:17])=[CH:5][C:6]=1[C:7](=[O:15])[C:8]1[CH:13]=[CH:12][CH:11]=[CH:10][C:9]=1[Cl:14].Cl.[N:19]([O-])=O.[Na+].[Cl:23][CH:24](C(C)=O)[C:25]([O:27][CH2:28][CH3:29])=[O:26].C([O-])(=O)C.[K+]>O.C(O)(=O)C>[Cl:14][C:9]1[CH:10]=[CH:11][CH:12]=[CH:13][C:8]=1[C:7]([C:6]1[CH:5]=[C:4]([CH2:16][CH3:17])[S:3][C:2]=1[N:1]=[N:19][CH:24]([Cl:23])[C:25]([O:27][CH2:28][CH3:29])=[O:26])=[O:15]

Participants

8

Reactant 5

HCID 313Hydrochloric AcidHCID 11858Ethyl 2-chloroacetoacetateHCID 517044Potassium AcetateHCID 13163365(2-Amino-5-ethylthiophen-3-yl)(2-chlorophenyl)methanoneHCID 23668193Sodium Nitrite

Product 1

HCID 53738285Ethyl [3-(2-chlorobenzoyl)-5-ethyl-2-thienyl]azochloroacetate

Reagents, catalysts & solvents 2

HCID 176Acetic AcidSolventHCID 962WaterSolvent3×

Procedure

To a stirred solution of 26.6 g. of 2-amino-3-(2-chlorobenzoyl)-5-ethylthiophene in 200 ml. of acetic acid and 30 ml. of concentrated hydrochloric acid is added dropwise a solution of 7.0 g. of sodium nitrite in 30 ml. of water under cooling on an ice-sodium chloride bath to prepare the corresponding diazonium salt solution. Then, the diazonium salt solution is added dropwise under cooling and stirring into a solution of 18.0 g. of ethyl 2-chloroacetoacetate and 40 g. of potassium acetate in 400 ml. of water. After the addition, the resulting solution is further stirred at room temperature for 1 hour, diluted with water and extracted with ether. After the ether layer is washed with water and dried over sodium sulfate, the solvent is removed by distillation The residue is dissolved in a mixture of ether and n-hexane and passed through a column containing 1 kg. of silica gel. Then, the fractions eluted with a mixture of ether and n-hexane (1:4) is combined and evaporated. The residue is crystallized from n-hexane to give ethyl [3-(2-chlorobenzoyl)-5-ethyl-2-thienyl]azochloroacetate as crystals. Recrystallization from ethanol gives yellow needles melting at 55° to 57° C.

Workup

  1. temperatureunder cooling
  2. additionAfter the addition
  3. stirringthe resulting solution is further stirred at room temperature for 1 hour
  4. extractionextracted with ether
  5. washAfter the ether layer is washed with water
  6. dry with materialdried over sodium sulfate
  7. customthe solvent is removed by distillation The residue
  8. dissolutionis dissolved in a mixture of ether and n-hexane
  9. additioncontaining 1 kg
  10. washThen, the fractions eluted with a mixture of ether and n-hexane (1:4)
  11. customevaporated
  12. customThe residue is crystallized from n-hexane

Sources & evidence

ORD record
ord-38077615b0e343598ece61f2ae9e5159
Source dataset
uspto-grants-1977_04
Patent number
US04017620

Reaction notes

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