An easy and direct method for the synthesis of 1,2,4-triazole derivatives through carboxylic acids and hydrazinophthalazine

Rivera, Gildardo; Bocanegra-García, Virgilio; Moreno, Antonio; Galiano, Silvia; Pérez, Silvia; Aldana, Ignacio; Monge, Antonio

doi:10.1590/s0100-40422008000300014

Cited by 3 publications

(2 citation statements)

References 7 publications

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“…There are a number of synthetic routes used to obtain triazolophthalazines; most of them are based on heterocyclic hydrazones or hydrazides as precursors. Triazolophthalazines can be obtained by coupling carboxylic acids derivatives with 1-hydrazinophthalazine hydrochloride in the presence of 1-ethyl-3-(3′-dimethylaminopropyl)-carbodiimide hydrochloride (EDC), triethylamine, 1-hydroxybenzotriazol (HOBT) and dichloromethane 20 or acetonitrile, 13d but the reaction time is relatively long: 24 h and 48 h, respectively. A one-step cyclization reaction can be carried out between substituted phthalazine and an appropriate acyl hydrazide in a refluxing solvent, 13a,c or between substituted 1-phthalazinylhydrazine and aromatic aldehydes in the presence of bromine or lead tetraacetate.…”

Section: Synthesismentioning

confidence: 99%

“…3). Due to the presence of water molecules, these chains are linked into an infinite twisted ladder composed of R 4 8 (20) and R 4 6 (16) rings in 1, whereas the methanol molecules in 3 participate in O-H⋯Cl hydrogen bonding, but they do not give a ladder-like motif. The pyridazine nitrogen atom (N2) does not participate in any specific non-covalent interaction in 1-3, but the crystal structures of neutral phthalazine hydrazones (2A, 3A) exhibit the N-H⋯N cyclic synthon, which links the hydrazones to the dimers (Fig.…”

Section: Structural Studies On Phthalazinylhydrazones and Their Chlor...mentioning

confidence: 99%

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Solid-state studies of phthalazinylhydrazones and triazolophthalazines: the role of the nitro group

Trzęsowska-Kruszyńska

2015

CrystEngComm

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Hydralazine is an antihypertensive drug, which is metabolized to hydrazone and fused triazole. A series of its derivatives: phthalazinylhydrazones, their chloride salts and triazolophthalazines possessing a nitro group has been synthesized and structurally characterized. A facile air promoted oxidative cyclization was proposed for the synthesis of triazolophthalazines from phthalazinylhydrazones. In contrast to the traditional synthetic methods, the reaction proceeds under mild conditions in the absence of additional transition metal catalysts or oxidants. Examination of the family of crystal structures of the compounds possessing a nitro group at different positions and without this group has allowed the determination of the steric and geometrical preferences for the occurrence of hydrogen and non-hydrogen bonding intermolecular interactions formed by nitro groups, and their effect on the molecular self-assembly of the solid state. The changes in the crystal packing caused by the change in the nitro group position and the presence of an additional linker group have been discussed. The description of intermolecular interactions has been combined with the analysis of the calculated interaction maps, and the differences in molecular packing have been correlated with the differences in the physical properties for the two polymorphic forms of one of the phthalazinylhydrazones.

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Section: Synthesismentioning

confidence: 99%

Section: Structural Studies On Phthalazinylhydrazones and Their Chlor...mentioning

confidence: 99%