Regiospecific synthesis of substituted vulpinic acids

Synthesis and antioxidant properties of pulvinic acids analogues

“…16 In infrared, a strong band at 2594 cm À1 , corresponding to a chelated hydroxyl, was observed for the E-alkene, while a strong band at 3524 cm À1 , due to a nonchelated hydroxyl, was observed for the Z-alkene. 23 It is then not surprising that the E-isomers, in which the hydroxyl group is chelated by the ester function, are distinctly less polar than the Z-isomers. Hence the synthetic sequence described allowed to prepare various compounds 4, in which the tetronic acid moiety is substituted by a methoxycarbonylmethylene in position 5 and by various aryl and heteroaryl groups in position 3.…”

One-pot synthesis and evaluation of novel 3-aryl-6-ethoxycarbonyl-4-hydroxy-2H-pyran-2-one as a potent cytotoxic agent

“…Experimental 1 H-NMR and 13 C-NMR spectra were recorded on a Bruker Avance II 400 NMR spectrometer at 400 MHz and 100 MHz, respectively. Chemical shis are reported as d values in parts per million (ppm) relative to tetramethylsilane (TMS) for all recorded NMR spectra.…”

11-(4-Fluorophenyl)-7,11-dihydrobenzo[f]furo[3,4-b]quinolin-10(8H)-one

“…Tetronic acid derivatives and their metabolites, of which vitamin C and penicillic acid are undoubtedly the most important, are widespread in nature (Neelakantan & Seshadri, 1959). Natural 4-ylidenetetronic acid derivatives known as pulvinic acids have been found as pigments in lichens and higher fungi (Weinstock et al, 1979). Tetronic acid derivatives are interesting because of their antibiotic, antitumour, anticoagulant, anti-epileptic, antifungal and anti-inflammatory properties (Foden & McCormick, 1975).…”