72-40-2

very slightly beige fine powder

47 g of sodium nitrite was dissolved in 1.2 liters of water; The solution was cooled to 0° C. 100 g of 5-aminoimidazole-4 carboxamide was dissolved in a solution of hydrochloric acid (80 ml of 36% HCL in 720 ml water) with stirring. The resultant 5-aminoimidazole-4 carboxamide hydrochloride solution was added slowly, drop-wise, over 20-30 minutes at 0-5° C. After the addition was completed, the reaction mixture was stirred for 10 minutes and filtered. The solid obtained was suspended in 400 ml DM water and stirred for 15 minutes. The suspension was filtered and suction-dried for 15 minutes. The obtained solid was suspended in 500 ml of THF and stirred for 15 minutes. The suspension was filtered and suction-dried for 15 minutes. Finally, the solid was dried at 45° C. to afford 4-Amino-5-imidazolecarboxamide hydrochloride.

Recrystallise the hydrochloride from EtOH. [Kuroda & Hakko JEst(1) Est(2)Heterocycl Chem 30 593 1993, Alhede et al. J Org Chem 56 2139 1991, Cheru et al. Heterocycles 24 1133 1992, Beilstein 25 II 221, 25 III/IV 4329.]