Comparison of measured and calculated lipophilicity of substituted aurones and related compounds.

A molecule library containing 55 aurone- and thioaurone-type structures has been designed and synthesised. Reversed phase high performance liquid chromatographic (RP-HPLC) method has been developed to separate these compounds and to characterise their lipophilicity by experimental method (k'). The experimental lipophilicity data have been compared with the computer calculated lipophilicity parameters (CLOGPs) of the same molecules. In general, good correlations between the measured and calculated lipophilicities have been found with the exception of structure isomers and compounds capable for hydrogen bonding. The chromatographic method was suitable to separate the structure (ortho and para) isomers of aurone and thioaurones and was sensitive enough to differentiate their lipophilicities. Our findings suggest the usefulness of the chromatographic method in fast characterisation of the lipophilicity of structurally closely related molecules.

Chemo- and diastereoselectivity in the dimethyldioxirane oxidation of 2,3-dihydro-4H-1-benzothiopyran-4-ones and 4H-1-benzothiopyran-4-ones. Unusual reactivity of 4H-1-benzothiopyran-4-one 1-oxides.

The oxidation of the 1-thiochromanones 1-3 by dimethyldioxirane (DMD) produced the corresponding sulfoxides 4-6 or sulfones 7-9; their relative amounts depended on the amount of oxidant used. A low diastereoselectivity was observed in the sulfoxidation of the 2-substituted 1-thiochromanones 2 and 3, due to the small steric differentiation during the DMD attack. An unusual reactivity pattern was found in the DMD oxidation of the 1-thiochromones 10-12, in that the sulfoxides 13-15 were more reactive toward the electrophilic oxidizing agent than the corresponding sulfides. The observed anomaly may be explained in terms of transannular stabilization of the transition structure (TS) for the sulfone formation, promoted through favorable conformational effects in the sulfoxide. Higher sulfoxide/sulfone ratios were found in solvents of greater hydrogen bond donor capacity, which is in accordance with the postulated stabilizing effect.

Synthesis of hypolipidemic silybin analog 3',4'-ethylenedioxyflavonoids.

For pharmacological investigation various types of silybin analogues have been synthesized. According to the results of preliminary tests, many of the prepared benzodioxane analogues of chalcones, chalcone epoxides, isoflavones, flavanones and aurones possessed hypolipidemic activity.

Synthesis, antibacterial and antifungal activity of 4-hydroxycoumarin derivatives, analogues of novobiocin.

3-Acylamino-, -arylsulfonylamino-, -(N'-arylureido)-, -arylideneamino- and -arylcarbamoyl-4-hydroxycoumarins have been synthesized and tested for antibacterial and antifungal activity. 3-Arylcarbamoyl-4-hydroxycoumarins have been shown to possess significant activity against Gram-positive bacteria; 3-acylamino-4-hydroxycoumarins have moderate antibacterial and antifungal effects whereas the additional compounds are inactive.