Benzylpyrrolylmethyl esters of cyclopropane carboxylic acids

#This invention relates to novel esters of substituted cyclopropane carboxylic acid, synthesis thereof and intermediates therefor, such esters being useful as pesticides.

#The novel compounds of the present invention are represented by the following generic formula (A): ##STR1## wherein, W is oxygen or sulfur;

#X is lower alkyl or halogen;

#The following examples are provided to illustrate the practice of the present invention. Temperature is given in degrees Centigrade. RT means room temperature.

#A mixture of 3-(4-chlorophenoxy)-2,2-dimethylcyclopropanecarboxylic acid (0.95 g, 3.95 mmol), thionyl chloride (0.342 ml, 4.74 mmol) and DMF (several drops) in 50 ml benzene is stirred at RT for 2 days. The solvent and excess thionyl chloride are evaporated under reduced pressure. The resulting acid chloride is dissolved in 50 ml benzene, and 3-benzylpyrrolylmethyl alcohol (3.95 mmol) and 0.482 g 4-dimethtylaminopyridine (3.95 mmol) are added. The mixture is left at 25.degree. for 18 hours and then heated under reflux for 2 hours. The mixture is then poured into water and extracted with ether. The organic phase is washed with dilute HCl, sat. NaHCO.sub.3, water and brine, dried and concentrated under vacuum. The crude product is purified by preparative TLC developing with 20% ethyl acetate/hexane to yield 3-benzylpyrrolylmethyl 3-(4-chlorophenoxy)-2,2-dimethylcyclopropanecarboxylate (A; R is hydrogen, X=X' is methyl, W is oxygen, R.sup.1 is 4-chlorophenyl).

#3-(4-Fluorophenoxy)-2,2-dimethylcyclopropanecarboxylic acid (3.40 mmol) is stirred together with 0.34 g (3.40 mmol) potassium bicarbonate in 10 ml THF/DMF (1:1) for 15 minutes. Then 3.40 mmol of 3-benzylpyrrolylmethyl methanesulfonate in 5 ml THF/DMF (1:1) is added and the mixture stirred for approximately 48 hours. The reaction is diluted with ether, washed with water (3X) and sat. NaCl, dried and solvent is removed. The crude product is purified by preparative TLC developing with 10% ethyl acetate/hexane to yield 3-benzylpyrrolylmethyl 3-(4-fluorophenoxy)-2,2-dimethylcyclopropanecarboxylate.