Synthesis of multi-functionalized benzofurans through the condensation of ninhydrin and phenols using SSA as a recyclable heterogeneous acid catalyst
A simple and efficient one-pot methodology has been developed for the synthesis of biologically important multi-functionalized 3-(2$$^{\prime }$$′-hydroxyaryl)-2-(2$$^{\prime }$$′-carboxyphenyl)benzofurans using silica sulfuric acid (SSA) as a heterogeneous acid catalyst in DMF medium. The significant advantages of this methodology are the use of SSA as a recyclable solid acid catalyst, operational simplicity, easy availability of the starting materials, and good yield of the products with high atom-economy.
Protonation of ninhydrin and indan-1,2,3-trione revisited: A combined theoretical and experimental study
Abstract The literature data on protonation of indan-1,2,3-trione and ninhydrin (indantrione hydrate) in acidic media are inconsistent, formation of dications at pH 3 and very low extent of protonation in superacid CF 3 SO 3 H were claimed. Our combined theoretical (DFT, MP2, CCSD) and experimental (NMR) study has shown that indantrione undergoes single protonation in CF 3 SO 3 H resulting in monocation formation. In more strong superacid FSO 3 H-SbF 5 dication is formed, but, contrary to the literary data, trication is not formed even in this superacid. Significant dependence of 13 C NMR chemical shifts of indantrione on media acidity allows using this compound as a convenient indicator of acidity in a broad range, from H 0  −3 to −25.
Target of inhibition by the anti-lipogenic antibiotic cerulenin of sterol synthesis in yeast.
Abstract The antibiotic cerulenin inhibited the incorporation of 14 C-acetyl-CoA by 67% at a concentration of 9 × 10 −6 M but not that of 14 C-HMG-CoA into the non-saponifiable fraction in a cell-free extract of Saccharomyces cerevisiae . Cerulenin markedly inhibited the activity of partially purified HMG-CoA synthase. No inhibition of acetoacetyl-CoA thiolase activity was observed in the same preparation of HMG-CoA synthase. Therefore, cerulenin inhibition of overall sterol synthesis may be accounted for by the specific inhibition of HMG-CoA synthase activity.