2-Chloro-1,4-naphthoquinone → N-(3-chloro-4-oxonaphthalen-1(4H)-ylidene)thiophene-2-sulfonamide

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

385.2 mg 2-chloro-1,4-naphthoquinone (11) was mixed with 326.4 mg thiophene-2-sulfonamide in 15 ml dichloromethylene, to which at 0° C. was added 2 ml TiCl4 dichloromethylene solution followed by 613.3 μl. The mixture was heated at 60° C. with M.W. for 15 min and the black mixture was poured into 100 ml ethyl acetate. The insoluble was removed by filtrate through a pad of celite. The filtrate was concentrated and the residue was suspended in dichloromethylene. The brown insoluble stuff was removed by filtration and the filtrate was again concentrated to dryness. The residue was suspended in ethyl acteate/hexane (1:1) and the yellow solid was filtered. The solid was washed with ethyl acteate/hexane (1:1) and dried over vacuum affording title compound 377.7 mg (55.9%) as a yellow solid. When TiCl4.2THF and THF were used instead, the reaction afforded the title compound 522 mg (77.3%) as a yellow solid, m.p.: 167-169° C.

Herkunft & Nachweise