Hydrochloric Acid → N'-(2-Amino-4,6-dichloro-5-pyrimidinyl)-N,N-dimethylmethanimidamide

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Reaction Steps

4,6-Dichloro-2,5-bis-{[(dimethylamino)methylene]amino}pyrimidine (Example 1, 5.87 g, 20.3 mmol) was dissolved in 95% ethanol (200 mL) and 6 N aqueous hydrochloric acid (13.5 mL) added. The solution was heated in an oil bath at 55° C. under nitrogen for 30 minutes, at which point TLC (silica gel, 5% methanol-chloroform) showed that starting material had been cleanly converted to a lower-Rf product. The cooled (ice bath) solution was adjusted to pH ˜8 with concentrated ammonium hydroxide and the resulting mixture (white precipitate formed) concentrated on a rotary evaporator to ˜5 mL to remove ethanol. Additional water (20 mL) was added and the cooled mixture was filtered. The white precipitate was washed with additional water (2×20 mL) and dried to give the title compound as a white powder (4.50 g, 95%), m.p. >dec 250° C.; mass spectrum (CI/CH4): 236, 234 (M+1); 1H-NMR (DMSO-d6) δ: 7.59 (s, 1, CH), 6.90 (s, 2, NH2), 3.00 and 2.94 (both s, 3 each, 2CH3); UV (pH 7 phosphate buffer) λmax: 328 nM (ε 4500), 255 (15,800).

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