Chlorosuccinimide → 5-Chloro-3-cyano-2-(1,1-dipropoxymethylenamino)thiophene

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Reaction Conditions

Reaction Steps

In a sulfonation flask, 3.02 g (0.012 mol) 3-cyano-2-(1,1-dipropoxymethylenamino)thiophene, are added, with stirring to 15 ml of absolute pyridine. The internal temperature is then raised to 60° C. and 1.9 g (0.0144 mol) N-chlorosuccinimide are added in three portions. After stirring for 3 hours at 60° C., the pyridine is removed in a water jet vacuum and the residue taken up in ethylacetate. The organic phase is washed twice with water and after drying, the solvent is removed in a water jet vacuum. The crude product is purified by column chromatography over silica gel (eluant: tert.butylmethylether/hexane 1:6). Yield: 3.5 g of 5-chloro-3-cyano-2-(1,1-dipropoxymethyleneamino)thiophene in the form of brownish crystals, m.p. 55-57° C.

Provenance & Evidence