Supramolecular architectures constructed with the skeletons of zinc(II) 2,2′-bipyridine and barbiturate anion: Synthesis and characterization

Dixit, N.N.; Goto, Keisuké; Mishra, Lallan; Roesky, Herbert W.

doi:10.1016/j.poly.2010.01.010

Cited by 12 publications

(9 citation statements)

References 42 publications

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“…In our earlier study it has been reported that LH 4 reacts with Zn(bpy) (NO 3 ) 2 2H 2 O, and provides a supramolecular structure consisting of two LH 3 − anion and one [Zn(bpy) 2 ·2H 2 O] 2+ cation together with seven cocrystallized water molecules [31]. Enthused by this study, a reaction of LH 4 was carried with another metal precursor 2,2′-bipyridyl-dinitratocopper(II)-dihydrate in anticipation that the Cu(II) ion, due to its distorted configuration and its redox active nature, may interact with the ligand LH 4 in a different way compared to Zn(II) ion.…”

Section: Synthesis and Characterizationmentioning

confidence: 99%

“…The X-ray diffraction study of the resulting complex provided a supramolecular structure of type [Zn(bpy) 2 · 2H 2 O]·(LH 3 ) 2 ·7H 2 O [31]. Enthused by this interesting observation, a reaction of barbiturate ligand (LH 4 ) was carried out with a Cu(II) ion coordinatively protected with 2,2′-bipyridine and bearing two substitutable NO 3 one-pot-reaction.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

One pot synthesis of Cu(II) 2,2′-bipyridyl complexes of 5-hydroxy-hydurilic acid and alloxanic acid: Synthesis, crystal structure, chemical nuclease activity and cytotoxicity

Dixit

Koiri

Maurya

et al. 2011

Journal of Inorganic Biochemistry

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Section: Synthesis and Characterizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

One pot synthesis of Cu(II) 2,2′-bipyridyl complexes of 5-hydroxy-hydurilic acid and alloxanic acid: Synthesis, crystal structure, chemical nuclease activity and cytotoxicity

Dixit

Koiri

Maurya

et al. 2011

Journal of Inorganic Biochemistry

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“…For example, oxadeazaflavines could be used as strong Michael acceptors, as was conducted for the addition of barbituric acid to produce 5-(2,4,6-trioxo-hexahydropyrimidin-5-yl)-1H-chromeno[2,3-d]pyrimidine-2,4(3H,5H)-dione, 21 which is used as anion for the preparation of Zn(II) complexes as water clusters. 41 Also, some oxadeazaflavines are sirtuin inhibitors, an important activity against aging, apoptosis and transgenic nematodes, 42 as well as effect against cancer cells.…”

Section: Discussionmentioning

confidence: 99%

Synthesis and mechanism of formation of oxadeazaflavines by microwave thermal cyclization of ortho-halobenzylidene barbiturates

Figueroa‐Villar¹,

Oliveira²

2011

J. Braz. Chem. Soc.

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A reação de ciclização térmica de o-halobenzilideno barbituratos foi desenvolvida como um simples e eficiente método para a preparação de oxadeazaflavinas. A utilização de condições de reação em estado sólido com irradiação de microondas forneceu os produtos em 5 min e com rendimentos entre 47 e 98%. Os resultados experimentais das sínteses e a análise termogravimétrica das reações concordam com os resultados da simulação do mecanismo por modelagem molecular, indicando que a reação ocorre através de uma ciclização hetero-Diels-Alder intra-molecular, seguida por um processo rápido de re-aromatização.The thermal cyclization reaction of o-halobenzylidene barbiturates was developed as an efficient and simple method for the preparation of oxadeazaflavines. The use of solid state reaction conditions with microwave irradiation afforded the products in 5 min with 47 to 98% yield. Experimental synthetic results and thermogravimetric reaction analyses agree with the molecular modeling mechanism simulation, indicating that this reaction occurs through an intramolecular hetero-Diels-Alder cyclization followed by fast re-aromatization. Keywords: oxadeazaflavines, o-halobenzylidene barbiturates, microwave irradiation, intramolecular hetero-Diels-AlderIntroduction pyrimidine-2,4-(3H)-diones or 10-oxa-5-deazaflavines) are interesting compounds with great potential as intermediates for the synthesis of new heterocyclic systems [1][2][3][4][5][6][7][8] and as selective organic oxidants under mild conditions.3 Also, derivatives and analogues of oxadeazaflavines display important bioactivity, being potential drugs.9-12 For many years, several chemists tried without success to prepare the simplest oxadeazaflavine by the direct reaction of barbituric acid with salicylaldehyde, [13][14][15] thus making necessary the use of more complex synthetic procedures to obtain the desired products. [1][2][3] In the beginning of the 1990 decade there were reported two new simple and complementary methods for the preparation of oxadeazaflavines from barbituric acid. 16,17 The first method uses the condensation reaction of salicylaldehyde and analogues with barbituric acid at room temperature to yield an orange oxonium salt that affords oxadeazaflavines under dehydrating conditions, 16 as shown in Scheme 1. Unfortunately, this method only functions well with salicylaldehydes without effective electron-withdrawing groups at the aromatic ring.The second method, which is based on the thermal cyclization of o-halobenzylidene barbiturates, can be applied with success to starting materials containing electron-withdrawing and electron-donating groups at the aromatic ring. 17 The draw of this last method is the need Scheme 1. Synthesis of oxadeazaflavines from salicylaldehyde and barbituric acid. 16Synthesis and Mechanism of Formation of Oxadeazaflavines J. Braz. Chem. Soc. 2102 for relatively long reaction times at high temperatures, for example 1.5 hours at 260 °C, affording oxadeazaflavines in medium to low yields (50% or lower). On the other hand, ...

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“…All of the solvents were purchased from E. Merk and were freshly distilled prior to use. The complexes Cu(bpy)(NO 3 ) 2 ·H 2 O and Cu(bpy)(MeCO 2 ) 2 ·H 2 O were synthesized using the reported procedure , whereas [Zn(bpy) 2 (H 2 O) 2 ](LH 3 ) 2 ·7H 2 O was reported by us recently . Elemental analysis and mass spectral measurements were carried out on a Carbo-Erba elemental analyzer 1108, and JEOL SX-102 mass spectrometer respectively.…”

Section: Methodsmentioning

confidence: 99%

Cytotoxicity of Cu(II) and Zn(II) 2,2′-Bipyridyl Complexes: Dependence of IC₅₀ on Recovery Time

Shi

Toms

Dixit

et al. 2010

Chem. Res. Toxicol.

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We measure the cytotoxicity of three metal complexes containing the 2,2'-bypyridine ligand, Cu(bpy)(NCS)(2), 1, [Cu(bpy)(2)(H(2)O)](PF(6))(2), 2, and Zn(bpy)(2)(NCS)(2), 3, toward neuroblastoma cells (SK-N-SH) and ovarian cancer cells (OVCAR-3) using two different cell assays. The cells were exposed to various concentrations of the compounds for 1 h and the percent inhibition of cell growth, I, measured for various times after exposure, i.e., as a function of the recovery time t. After developing the theory showing the relationship between I and t, the cytotoxicity data were analyzed to reveal that the two copper complexes, 1 and 2, cause the cells to divide at a slower rate than the controls during the recovery period, but the zinc complex, 3, had little or no effect on cell division during the recovery period. The usual metric for reporting cytotoxicity is IC(50), which is the concentration of agent required to inhibit cell growth to 50% of the control population. However, since IC(50) can depend on the recovery time, t, as is the case for 1 and 2, reporting IC(50) for a single recovery time can hide important information about the long-time effects of a cytotoxic agent on the health of the cell population. Mechanistic studies with the compounds revealed that the copper complexes, 1 and 2, cleave closed circular pBR322 DNA in the presence of ascorbate, while the zinc complex, 3, does not facilitate DNA cleavage under the same conditions. This difference in DNA cleavage activity may be related to the fact that Cu(II) is redox active and can readily change its oxidation state, while Zn(II) is redox inert and cannot participate in a redox cycle with ascorbate to break DNA.

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Supramolecular architectures constructed with the skeletons of zinc(II) 2,2′-bipyridine and barbiturate anion: Synthesis and characterization

Cited by 12 publications

References 42 publications

One pot synthesis of Cu(II) 2,2′-bipyridyl complexes of 5-hydroxy-hydurilic acid and alloxanic acid: Synthesis, crystal structure, chemical nuclease activity and cytotoxicity

One pot synthesis of Cu(II) 2,2′-bipyridyl complexes of 5-hydroxy-hydurilic acid and alloxanic acid: Synthesis, crystal structure, chemical nuclease activity and cytotoxicity

Synthesis and mechanism of formation of oxadeazaflavines by microwave thermal cyclization of ortho-halobenzylidene barbiturates

Cytotoxicity of Cu(II) and Zn(II) 2,2′-Bipyridyl Complexes: Dependence of IC₅₀ on Recovery Time

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Supramolecular architectures constructed with the skeletons of zinc(II) 2,2′-bipyridine and barbiturate anion: Synthesis and characterization

Cited by 12 publications

References 42 publications

One pot synthesis of Cu(II) 2,2′-bipyridyl complexes of 5-hydroxy-hydurilic acid and alloxanic acid: Synthesis, crystal structure, chemical nuclease activity and cytotoxicity

One pot synthesis of Cu(II) 2,2′-bipyridyl complexes of 5-hydroxy-hydurilic acid and alloxanic acid: Synthesis, crystal structure, chemical nuclease activity and cytotoxicity

Synthesis and mechanism of formation of oxadeazaflavines by microwave thermal cyclization of ortho-halobenzylidene barbiturates

Cytotoxicity of Cu(II) and Zn(II) 2,2′-Bipyridyl Complexes: Dependence of IC50 on Recovery Time

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Cytotoxicity of Cu(II) and Zn(II) 2,2′-Bipyridyl Complexes: Dependence of IC₅₀ on Recovery Time