X-ray diffraction examination of the molecular structure of guanazole (3,5-diamino-1h-1,2,4-triazole)
In the case of guanazole, five isomeric forms can exist. From the study of UV and IR spectra, amino-imine [i], diimine [2] and diamine [3] structures have been attributed to guanazole. According to the data of the quantum-chemical calculation of the heat of formation, the diamine asymmetric form is the most probable structure [4]. To unequivocally determine the structure of the guanazole molecule in the crystalline state, we carried out out an x-ray diffraction study.
A tetrasaccharide, corresponding to the heparan sulfate heparanase substrate, namely beta-D-GlcA(2S)-(1-->4)-alpha-D-GlcN(NS,6S)-(1-->4)-beta-D-GlcA-(1-->4)-alpha-D-GlcN(NS,6S)-OMe, was synthesized in a convergent manner via coupling of a pair of the disaccharide building blocks as a key step.