3,5,5-Trimethyl-2-pyrazoline → 1-(2,6-Dichlorophenylsulphonylcarbamoyl)-3,5,5-trimethyl-2-pyrazoline

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Reaction Steps

11.2 g of the 3,5,5-trimethyl-2-pyrazoline obtained according to example I(b) are added dropwise while stirring, cooling in cold water and under a nitrogen blanket to a solution of 25.2 g of the 2,6-dichlorobenzenesulphonylisocyanate obtained according to example I(a) in 200 ml of dry toluene. After stirring at room temperature for two hours, the precipitate is sucked off and washed successively with dry toluene and petroleum ether (40-60). The desired 1-(2,6-dichlorophenylsulphonylcarbamoyl)-3,5,5-trimethyl-2-pyrazoline is obtained in a yield of 20.07 g; melting-point 270° C. (decomposition).

Provenance & Evidence