Crystal structures of the nitrate salt of 24-pyrimidinium crown 6 {5,12,19,26,33,40-hexaamino-3,10,17,24,31,38-hexamethyl[1.(6)]-(1,5)pyrimidiniophane} and its degradation product in water-methanol mixtures

Reflux of thiamin [3-(4-amino-2-methylpyrimidin-5-ylmethyl)-5-(2-hydroxyethyl)-4-methylthiaxzolium] mononitrate in methanol for 2 h, followed by recrystallization from methanol, produced single crystals of [L][NO3](6) . 16H(2)O {L = 5,12,19,26,33,40-hexaamino-3,10,17,24,31,38-hexamethyl[l.(6)](1,5)pyrimidiniophane, or 24-pyrimidinium crown 6}. The compound crystallizes in the rhombohedral space group R (3) over bar, a = b = c = 14.131(11) Angstrom, alpha = beta = gamma = 115.26(5)degrees, Z = 1, R = 0.0469, 1352 independent reflections with F> 2.0 sigma(F). Reflux of [L][NO3](6) . 16H(2)O in methanol-water (3:2) for 182 h produced single crystals of the nitric acid salt of 4-amino-5-methoxymethyl-2-methylpyrimidine. The compound crystallizes in the triclinic space group P (1) over bar, a = 9.116(6), b = 9.452(5), c = 12.742(8) Angstrom, alpha = 101.14(5), beta = 107.13(5), gamma = 93.27(5)degrees, Z = 4, R = 0.0644, 2690 independent reflections with F> 2.0 sigma(F). The nitric acid salt of 4-amino-2-methylpyrimidine-5-methanol has been isolated and identified by H-1 NMR spectroscopy from the thermal decomposition reaction of [L][NO3](6) . 16H(2)O in water. The alcohol has also been observed by H-1 NMR spectroscopy in the decomposition of [L](6+) in aqueous solutions at room temperature.