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Open Chemistry
|
2012
|
vol. 10
|
issue 4
1218-1222
EN
A new organometallic complex coupling photoactive coumarin to a diironhexacarbonyl unit has been successfully prepared and its composition and electronic structure confirmed by elemental and spectroscopic analyses. Emission spectral analysis of the complex reveals photoinduced intramolecular electron transfer from coumarin to the iron-carbonyl moiety. The compound is electrochemically reduced at −1.24 V vs. Fc/Fc+. This reduction is irreversible, attesting to the instability of the complex. Electrochemical evolution of hydrogen in the presence of the complex has been studied and results are discussed. [...]
EN
This work concentrated on the utility of hydrazonoyl halides in synthesis of bioactive heterocycles like triazoles, pyrazoles, pyrimidines and their fused derivatives which have a wide spectrum of pharmaceutical value. Herein we discussed the synthesis of new heterocyclic compounds containing fused pyrimidine rings derived from hydrazonoyl halides and their significant pharmaceutical importance as anticancer agents. New fused pyrimidine derivatives bearing 1,2,3-triazole moiety were prepared via reaction of enaminone 2 with and 6-amino-2-thioxo-pyrimidin-4-one and then with hydrazonoyl chlorides 6a-h. In addition 3-amino-6-(2-oxo-2H-chromen-3-yl)pyridine-2-carbonitrile (12) was submitted to react with carbon dioxide to afford 3-(1,2,3,4-tetrahydro-2,4-dithioxopyrido[2,3-d]pyrimidin-7-yl)-2H-chromen-2-one (15), which act as key molecule for synthesis of new series of fused prymidinethione derivatives containing coumarine moiety via its reaction with different selected derivatives of hydrazonoyl halides 6a-h. Structures of the newly synthesized compounds were confirmed using spectral data (IR, H1NMR and Mass spectrometry) and microanalytical methods. Also, they screened for their anticancer activity.
EN
A binuclear copper complex [{Cu(L)2}2], C68H48Cu2N4O12C (where L is 4-methyl-7-(salicylideneamino)coumarin), has been synthesized and characterized using elemental analysis, molar conductance measurements, and infrared, ultraviolet and ESR spectrosopy. The molecular structure of title compound, determined by single-crystal X-ray diffraction studies, reveals that the two symmetric Cu(L)2 units are associated into a dimer by rather long Cu...O bonds. The Cu(II) ions are bridged via the phenolic oxygen of one of the monomers and have distorted trigonal bipyramidal conformation geometry. Within each monomer the two methylsubstituted coumarin skeletons are trans to one another, but adopt a parallel arrangement with respect to the other monomer. Only half of the complex molecule can be found in the asymmetric unit, Z′ = 0.5, the other half is generated by the symmetry centre. [...]
EN
The key 3-(2-oxo-2H-chromen-3-yl)-2-oxo-2H,5H-pyrano[3,2-c]chromen-5-yl acetates 3 were synthesized in high yields by cyclocondensation of 4-oxo-4H-chromen-3-carbaldehydes 1 with coumarin-3-acetic acids 2 under mild conditions. The reaction pathway involves aldol condensation and subsequent intramolecular lactonization to afford 2-oxo-2H,5H-pyrano[3,2-c]chromene skeleton 3. Further treatment of acetates 3 with alcohols, water or nitrogen containing compounds led to 5-alkoxy-, 5-hydroxy- or 5-acylamino-2H,5H-pyrano[3,2-c]chromen-2-ones 4-6 via nucleophilic substitution of acetyloxy group at C-5. Acetates and hydroxyl derivatives 3 and 5 undergo facile rearrangement in an acid medium yielding 5-hydroxypyrano[2,3-b]chromen-2(10aH)-ones 7. [...] Twelve prepared compounds were evaluated on their antineoplastic activities on 60 human tumour cell line panels in NCI USA. The obtained biological results confirmed that 3-(2-oxo-2H-chromen-3-yl)-2H,5H-pyrano[3,2-c]chromen-2-one represents a new leading skeleton suitable for further antitumour activity study.
EN
A series of twelve hybrid coumarin analogues were synthesized and screened through HTS for their antimycobacterial activity against Mtb H37Rv. The hybrid molecules were efficiently synthesized by the reactions of 3-(bromoacetyl)coumarin with Biginelli products 2-mercapto-6-oxo-4-aryl-1,6-dihydropyrimidine-5-carbonitriles. Of the resulting twelve hybrids, the two compounds 7-(2,4-dichlorophenyl)-5-oxo-3-(2-oxo-2H-chromen-3-yl)-5H-thiazolo[3,2-a] pyrimidine-6-carbonitrile (3d) and 7-(4-nitrophenyl)-5-oxo-3-(2-oxo-2H-chromen-3-yl)-5H-thiazolo[3,2-a]pyrimidine-6-carbonitrile (3f) showed excellent antimycobacterial activity against Mtb (EC50 3.19 & 7.91 µM, respectively) and low cytotoxicity against the VERO cell line (IC50 > 62.5 µg/mL).
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