Dipropylamine → HCID 178473545, Verbindung

A mixture of 0.02 mol (4.10 g) of 3-amino-2-azocanopyridine and 0.02 mol of ethoxy-carbonyl isothiocyanate is stirred at ambient temperature for 3 hours in 100 ml of DMF, by which means the thiourea of formula (IV) is obtained, which it is not necessary to isolate. The solution is cooled to 0° C. and saturated with 2.5 eq. of di-n-propylamine, and 0.02 mol of mercuric chloride is added; at the end of 15 minutes, the ice bath is removed and the mixture is stirred at ambient temperature for 3 hours (the black precipitate caused by the formation of mercury sulphide will still be seen to appear). After having added 150 ml of ethyl acetate, the solution is filtered over Celite and the solvents are evaporated off under reduced pressure. The crude N-ethoxycarbonylguanidine thereby obtained is again dissolved in 50 ml of DMF and heated at reflux for 2 hours. After the hot solution has been filtered in order to remove the last remnants of mercury salt, the DMF is evaporated off under reduced pressure. The solid thereby obtained is taken up in a minimum of acetonitrile, filtered off over a frit under suction and then recrystallised from acetonitrile.