Triethylamine → 8-Methyl-6-(1,2,5,6-tetrahydropyridin-1-yl)-1,2,4-triazolo[4,3-b]pyridazine

Beteiligte Stoffe

Reaktionsschritte

A solution of 84.3 g of 6-chloro-8-methyl-1,2,4-triazolo [4,3-b]pyridazine, 62.4 g of 1,2,5,6-tetrahydropyridine and 101 g of triethylamine in one liter of ethanol was refluxed under nitrogen for 21 hours. The bulk of the solvent was removed at the rotary evaporator. The residual semi-solid was dissolved in 1000 ml of dichloromethane and washed with 500 ml of saturated sodium bicarbonate solution. The aqueous layer was back washed with fresh dichloromethane (2×200 ml) and the combined organic layers were dried over anhydrous sodium sulfate. Evaporation of the solvent gave a light-brown oil which slowly solidified. This was taken up in 230 ml of hot ethyl acetate and cooled. After cooling the mixture slowly to room temperature and then to 5° C., the cream colored needles which formed were collected, washed with ethyl ether/ethyl acetate (2/1) then with ethyl ether and dried to give 8-methyl-6-(1,2,5,6-tetrahydropyridin-1-yl)-1,2,4-triazolo-[4,3-b]pyridazine melting at about 103°-106° C.

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