ETHYL 2,3-DICHLOROBENZOYLFORMATE synthesis

Yield:-

Reaction Conditions:

with magnesium in water;cadmium(II) chloride;benzene;

Steps:

9 ethyl oxalyl chloride (0.079M, 10.9 g, 8.92 ml)

Method A Grignard reagent was prepared in conventional manner as follows: The dichloroiodobenzene was added to magnesium over 1-2 hours and the resulting solution was refluxed for about 4 hours. As all the Mg had not dissolved the Grignard was allowed to stir at room temperature overnight. The flask was then cooled in ice and the dry cadmium chloride added portionwise over 10 minutes. When all the cadmium chloride had been added the reaction mixture was allowed to warm to room temperature and was then heated under reflux for 45 minutes. The ether was evaporated off and the residue washed twice with dry benzene which, in was turn, also evaporated off. The residue was then taken and treated with ethyl oxalyl chloride in 20 mls dry benzene. This was added slowly from a dropping funnel with stirring. The reaction was very vigorous. When addition was complete and spontaneous reflux had subsided the reaction mixture was refluxed for a further hour. The reaction mixture was then cooled in an ice bath. Ice/water was carefully added. Sufficient 20% H₂ SO₄ was then added to give two clear phases. The aqueous phase was separated and extracted twice with benzene. The benzene layers were combined and extracted 1*water, 1*Na₂ CO₃ solution, 1*water and 1*NaCl solution. The benzene solution was then dried over MgSO₄, filtered and evaporated down. 17.5 g crude material was obtained. NMR and TLC analyses were performed. TLC in Si/CHCl₃ gave two spots, one corresponding to the title compound (product) and one to the dichloroiodobenzene (starting material).

References:

US5912345,1999,A