Reactions of Nucleophilic Substitution in Bicyclic Nitroimidazodihydrooxazoles

This article describes numerous attempts of the S_N reaction of chlorine atom in chloromethyl group with nucleophilic compounds, such as the following: phenols, thiophenols, and amino compounds. The influences of ratios of nitroimidazodihydrooxazoles, nucleophiles and basic agent, and the polarity of solvent on the kind of formed products were established. Also, the comparison of reactivity with nucleophiles of close structural isomers of nitroimidazodihydrooxazoles has been made. The way of formation ring opening reaction products has been proposed.     

Triterpenoids. Part IV. Mass spectrometry of pentacyclic triterpenoids: 18β- and 18α-11-oxooleanolic acid derivatives

The mass spectral fragmentation of five pairs of 18β- and 18α-11-oxooleanolic acid derivatives 1a, 1b–5a, 5b are investigated and discussed. Fragmentation pathways, elucidation of which were assisted by accurate mass measurements and metastable transitions, are proposed, The obtained data create a safe basis for distinguishing the above-mentioned 18 diastereomers.     

Synthesis of novel spiro-condensed 2-amino-4H-pyrans based on 1,2-benzoxathiin-4(3H)-one 2,2-dioxide

Chemistry of Heterocyclic Compounds - A series of new spiro-condensed 2-amino-4H-pyrans were synthesized by three-component interaction of 1,2-benzoxathiin-4(3H)-one 2,2-dioxide, malononitrile, and...     

Anticancer effect of A-ring or/and C-ring modified oleanolic acid derivatives on KB, MCF-7 and HeLa cell lines

New A-ring or/and C-ring modified methyl oleanolate derivatives were prepared. New simple method of synthesis of 3,12-diketone (3) from methyl oleanonate (2) was worked out. The obtained new compounds were tested for cytotoxic activity on KB, MCF-7 and HeLa cell lines. The derivatives had acetoxy, oxo or hydroxyimino function at the C-3 position and in some cases oxo, hydroxyimino or acyloxyimino group at the C-12 position. Almost all of the compounds showed strong cytotoxic activity, higher than unchanged oleanolic acid. The most active substances turned out to be the derivatives with acyloxyimino function, especially 4 and 8d.