2-Oxobutanoic Acid → Z-2-(2,2-dichlorocyclopropanecarboxamido)-2-butenoic acid

HRID 979430Notes

Reaction equation

HRID 979430 reaction equation
O=[C:2]([CH2:6][CH3:7])[C:3]([OH:5])=[O:4].[Cl:8][C:9]1([Cl:15])[CH2:11][CH:10]1[C:12]([NH2:14])=[O:13]>C1(C)C=CC=CC=1>[Cl:8][C:9]1([Cl:15])[CH2:11][CH:10]1[C:12]([NH:14]/[C:2](=[CH:6]\[CH3:7])/[C:3]([OH:5])=[O:4])=[O:13]

Participants

4

Reactant 2

HCID 582-Oxobutanoic AcidHCID 5419272,2-Dichlorocyclopropane-1-carboxamide

Product 1

HCID 13505572Z-2-(2,2-dichlorocyclopropanecarboxamido)-2-butenoic acidYield 17.8%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

A mixture of 1.53 g (15 mmoles) of 2-ketobutyric acid, 1.54 g (10 mmoles) of 2,2-dichlorocyclopropanecarboxamide and 10 ml of toluene was heated under reflux for 12 hrs. with removal of H2O by a modified Dean-Stark trap containing molecular sieves (4A). An additional 0.7 g of 2-ketobutyric acid was added and the reaction mixture was heated under reflux for an additional 12 hrs. The mixture was cooled, diluted with 20 ml of toluene and extracted with saturated sodium bicarbonate (3×10 ml). The extracts were combined, washed with ether and acidified to pH 3 (pH meter) with concentrated hydrochloric acid. A gum precipitated which soon solidified. It was filtered, washed with water, dried and recrystallized from nitromethane to give 423 mg of Z-2-(2,2-dichlorocyclopropanecarboxamido)-2-butenoic acid, m.p. 188°-189.5° C. The NMR spectrum was in accord with the desired structure.

Workup

  1. temperaturewas heated
  2. temperatureunder reflux for 12 hrs
  3. customwith removal of H2O by a modified Dean-Stark trap
  4. additioncontaining molecular sieves (4A)
  5. additionAn additional 0.7 g of 2-ketobutyric acid was added
  6. temperaturethe reaction mixture was heated
  7. temperatureunder reflux for an additional 12 hrs
  8. temperatureThe mixture was cooled
  9. additiondiluted with 20 ml of toluene
  10. extractionextracted with saturated sodium bicarbonate (3×10 ml)
  11. washwashed with ether
  12. customA gum precipitated which
  13. filtrationIt was filtered
  14. washwashed with water
  15. customdried
  16. customrecrystallized from nitromethane

Sources & evidence

ORD record
ord-d8321aeee0ae4388a4191b810f00e726
Source dataset
uspto-grants-1987_05
Patent number
US04668504

Reaction notes

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