2,6-Difluorobenzoyl isocyanate → Flucycloxuron

Participants

Reaction Steps

36.6 g of 2,6-difluorobenzoylisocyanate in 50 ml of dry diethyl ether were added to a solution of 59.0 g 4-(α-cyclopropyl-4-chlorobenzylideneaminooxymethyl)aniline in 700 ml of dry diethylether with external cooling at 0°-10° C. After stirring for 3 hours at 0°-10° C. the formed precipitate was sucked off, washed with diethyl ether, and dried. The product obtained in a yield of 76.0 g was chromatographed over silica, chloroform being used as an eluent. The desired product was isolated in a yield of 60,7 g having a purity of at least 95% (PMR). The product obtained had a melting range of 145°-175° C. and comprised the syn- and anti-form in approximately equal amounts. In another experiment the desired product was obtained as a mixture of the syn- and anti-form in a ratio of 85:15; melting point 187°-191° C.

Provenance & Evidence