| Abstrakt: |
Four 1-aryl-1H-pyrazole-3,4-dicarboxylate derivatives, one acid, two esters and a dicarbohydrazide have been synthesized starting from 3-aryl sydnones, and structurally characterized. There is an intramolecular O—H. . .O hydrogen bond in 1-phenyl-1H-pyrazole-3,4-dicarboxylic acid, C11H8N2O4, (I), and the molecules are linked into a three-dimensional framework structure by a combination of O—H. . .O, O—H. . .N, C—H. . .O and C—H. . .π(arene) hydrogen bonds. In each of the two esters dimethyl 1-phenyl-1H-pyrazole-3,4-dicarboxylate, C13H12N2O4, (II), and dimethyl 1-(4-methylphenyl)-1H-pyrazole-3,4-dicarboxylate, C14H14N2O4, (III), C—H. . .O hydrogen bonds lead to the formation of cyclic centrosymmetric dimers: in (III), one of the methoxycarbonyl groups is disordered over two sets of atomic sites having occupancies 0.71 (2) and 0.29 (2). An intramolecular N—H. . .O hydrogen bond is present in the structure of 1-(4-methoxyphenyl)-1H-pyrazole-3,4-dicarbohydrazide, C12H14N6O3, (IV), and the molecules are linked into a three-dimensional framework structure by a combination of N—H. . .O, N—H. . .N, N—H. . .π(arene) and C—H. . . O hydrogen bonds. Comparisons are made with the structures of a number of related compounds. [ABSTRACT FROM AUTHOR] |
