Synthesis and physiological effects of new 4-aminophenol derivatives as paracetamol analogues.

Paracetamol has antipyretic and analgesic properties and it is widely used for fever and pain. However, paracetamol is partially metabolized to N-acetyl-p-benzoquinoneimine, which in overdose leads to liver necrosis, urging for safer paracetamol analogues. As the latter, new para-aminophenol derivatives containing fragments of acetic acid, saturated fatty acids and monoethanolamine were synthesized.

Spectral-luminescent properties of 12-oximino derivatives of 8-AZA-D-homogona-12,17a-diones and their concentration dependence.

This paper presents the results of the investigation of the spectral-luminescent characteristics of 12-oximino derivative of 8-aza-D-homogona-12,17a-dion, its hydrochloride, and their dependences on the concentration. It has been shown that the form and position of the absorption spectrums of 16,16-dimethyl-12-oximino-8-aza-D-homogona-1,3,5(10),13-tetraene-17a-one in all solvents used are independent of its concentration. At the same time, for its hydrochloride in ethanol and water, a strong dependence of the absorption spectrum on its concentration has been revealed.

Phosphorescence of 8-azasteroids and related compounds.

We have investigated the electron absorption, fluorescence and phosphorescence spectra of 8-azasteroids and model compounds containing enaminodicarbonyl fragment. It has been shown that the investigated compounds have absorption and phosphorescence spectra similar in form and position. The results obtained permit the conclusion that the main deactivation channel of the excited singlet state is the intersystem crossing.

Fast relaxation processes and structural changes in immunoactive biomolecules.

Based upon an analysis of the absorption spectra, the fluorescence and fluorescence excitation spectra, and the lifetime of the excited states of aqueous solutions (pH 7.4) of 2,3-dimethoxy-8-azagona-1,3,5(10),13-tetraene-12,17-dione, it is established that two centers of different type exist: one emits long-wave (L-centers) and the other short-wave (S-centers) fluorescence. Irradiation of solutions increases the number of L-centers and greatly decreases that of S-centers.

Enantioconvergent synthesis of (-)-(S)- and (+)-(R)-2-acetyl-3,6-dihydroxycyclohex-2-enone starting from rac-6-hydroxy-3-methoxycyclohex-2-enone.

The synthesis of enantiomerically pure (-)-(S)- and (+)-(R)-2-acyl-3,6-dihydroxycyclohex-2-enone starting from diastereomerically pure N-tosyl-(S)-proline esters 3-methoxy-6-hydroxycyclohex-2-enone 1 is presented. An enantioconvergent synthesis of either (-)-(S)- and (+)-(R)-2-acyl-3,6-dihydroxycyclohex-2-enone starting with the racemic alpha-ketol 1 through a conversion of ( approximately 1:1) mixture of diastereomeric esters into one diastereomer by a repeated crystallization, followed by dimethylaminopyridine-catalyzed equilibration as key steps is described.