[N:1]1([CH2:7][C:8]([N:10]2[CH2:15][CH2:14][O:13][CH2:12][CH2:11]2)=[O:9])[CH2:6][CH2:5][NH:4][CH2:3][CH2:2]1.Cl.[O-:17][C:18]#[N:19].[K+].[OH-].[Na+]>O>[NH2:19][C:18]([N:4]1[CH2:3][CH2:2][N:1]([CH2:7][C:8]([N:10]2[CH2:11][CH2:12][O:13][CH2:14][CH2:15]2)=[O:9])[CH2:6][CH2:5]1)=[O:17]
9.1 g of piperazin-1-yl-acetic acid morpholide are dissolved in 30 ml of water and 4.4 ml of concentrated hydrochloric acid and the solution is cooled to 20° C. A solution of 3.1 g of potassium cyanate in 15 ml of water is slowly added dropwise, with cooling. A further 4.4 ml of concentrated hydrochloric acid are then added and the mixture is left to stand overnight at 20° C. The solution is rendered neutral with 2N sodium hydroxide solution and concentrated. Boiling up of the solid residue with isopropanol and cooling of the solution gives 5.3 g of colourless crystals, which are recrystallised from ethanol.
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