Microwave-assisted synthesis of derivatives of khellinone under phase-transfer catalytic conditions

Microwave-assisted preparation, structural characterization, lipophilicity, and anti-cancer assay of some hydroxycoumarin derivatives

ABSTRACT

A new series of hydroxycoumarin derivatives has been synthesized using conventional synthesis. The syntheses were accelerated by microwave assistance. Yields in both cases were comparable (59-69 %). The structures were established by 1H and 13C NMR spectroscopy and high-resolution mass spectrometry. Five compounds (5-hydroxy-4,7-dimethylcoumarin, 6-acetyl-5-hydroxy-4,7-dimethylcoumarin, 4-(cyanomethoxy)chromen-2-one, 5-(cyanomethoxy)-4,7-dimethylchromen-2-one, and 6-acetyl-5-(cyanomethoxy)-4,7-dimethylchromen-2-one) were assayed for anti-cancer activity. For all presented coumarin derivatives, lipophilicity was measured using reversed-phase TLC in different eluent systems with standardization. In addition, the crystal structure of 6-acetyl-5-hydroxy-4,7-dimethylcoumarin has been solved by X-ray structure analysis of single crystals.

GRAPHICAL ABSTRACT

Synthesis and pharmacological activity of O-aminoalkyl derivatives of 7-hydroxycoumarin

A series of novel O-aminoalkyl substituted 7-hydroxycoumarins were synthesized and evaluated for antibacterial and anticancer toxicity. Two different synthetic procedures, conventional and microwave assisted were used, and the structures of the compounds were confirmed by IR, 1H, 13C NMR and MAS spectroscopic data. The molecular and crystal structures of 8-acetyl-7-[2-(1-morpholino)ethoxy]4-methylchromen-2-one in solid state were analyzed by single crystal X-ray diffraction. The compound crystallizes in the monoclinic space group P2(1)/c. The main driving forces for the supramolecular structure are the C-H⋯O hydrogen bonds and the π⋯π intermolecular interactions. The most active compounds are those, where the O-aminoalkyl substituent has N,N-diethylamino part, and acetyl group is at C6 or at C8 atoms.