866143-84-2Relevant academic research and scientific papers
Structural evaluation of three 2-phenylpyrazolo[4,3-c]quinolin-3-one monohydrates
Ferreira, Vitor F.,Leal, Katia Z.,Lindgren, Eric B.,De Oliveira, Mara R.P.,De Souza, Maria Celia B.V.,Vasconcelos, Thatyana R.A.,Wardell, James L.,Wardell, Solange M.S.V.,Yoneda, Julliane D.
, p. 299 - 309 (2013)
A single crystal X-ray diffraction and theoretical study has been carried out on mono hydrates of three 2H-pyrazolo[4,3-c]quinolin-3(5H)-one derivatives, namely 6-methyl-2-phenylpyrazolo[4,3-c]quinolin-3-one, 3, 6-methyl-2-(4- chlorophenyl)pyrazolo[4,3-c]quinolin-3-one, 4, and 8-methyl-2-(4-nitrophenyl) pyrazolo[4,3-c]quinolin-3-one, 5. The monohydrates were obtained on recrystallization from moist solvents. While there are three tautomeric forms possible for such pyrazolo[4,3-c]quinolin-3-one molecules, the sole form isolated in the solid [(X)×(H2O)] (X = 3, 4 and 5) compounds was the quinoloid form - the one calculated to be the most stable at the M06-2X/6-311++G(d,p) level of theory. Excellent agreement was found between the calculated and X-ray determined structures. Molecule 5 in [(5)×(H 2O)] is very near planar while both molecules 3 and 4 in their respective hydrates are much less so as a consequence of angles about 24 between the two aromatic rings. In each hydrate, the pyrazolo[4,3-c]quinolin-3-one molecule is bonded to three water molecules and each water molecule is likewise H-bonded to three pyrazolo[4,3-c]quinolin-3-one molecules. While the water molecules are H-bonded to 3 and 4 via the pyridinyl N and 2x the carbonyl O atoms, in [(5)×(H2O)] the H-bonds are to pyridinyl N, carbonyl O and a nitro O atoms. Calculations indicated that the found arrangement in [(5)×(H2O)] is more stable than one using the connections as found in [(3)×(H2O)] and [(4)×(H2O)]. While each of the hydrates possess strong N-H?O and O-H?O hydrogen bonds, and weaker C-H?π and π?π interactions, the supramolecular arrays are very different.
