Jan Svetlik

Monastrol analogs: A synthesis of pyrazolopyridine, benzopyranopyrazolopyridine, and oxygen-bridged azolopyrimidine derivatives and their biological screening

A synthesis of novel pyrazolopyridine, benzopyranopyrazolopyridine, and oxygen-bridged pyrazolo-, tetrazolo-, benzimidazo-, and thiazolopyrimidines via Hantzsch- and Biginelli-like condensations has been developed. The ability of these compounds to inhibit Eg5 activity has been examined. The results indicate that synthetic manipulations in the monastrol thiourea moiety are inefficient.

Expedient Synthesis of 3-Arylpropionic Acid Derivatives

Abstract A direct synthesis of 3-aryl-3-substituted propionic esters and amides is described starting from Meldrums acid, dimedone or 4-hydroxycoumarin and an aldehyde.

Selective inhibitory action of Biginelli‐type dihydropyrimidines on depolarization‐induced arterial smooth muscle contraction

Objectives  Dihydropyridine calcium channel blockers have some disadvantages such as light sensitivity and relatively short plasma half‐lives. Stability of dihydropyrimidines analogues could be of advantage, yet they remain less well characterized. We aimed to test four newly synthesized Biginelli‐type dihydropyrimidines for their calcium channel blocking activity on rat isolated aorta.

4,5-dihydro-5,5-dimethyl-3-oxo-3H-1,2,4-triazole-1-oxide. The unpredicted azoxy-regioisomer

Summary4,5-Dihydro-5,5-dimethyl-3-oxo-3H-1,2,4-triazole (1) is converted to the title azoxy compound4 by peroxytrifluoroacetic acid. The structure assignment of4 is based on an X-ray analysis.Ab initio calculations were employed to rationalize the reaction path leading to the triazole-1-oxide4 and not to the expected regioisomer triazole-2-oxide3.Zusammenfassung4,5-Dihydro-5,5-dimethyl-3-oxo-3H-1,2,4-triazol (1) wird mit Trifluorperessigsäure in die Titel-Azoxy-Verbindung4 umgewandelt. Die Strukturzuordnung von4 basiert auf einer Röntgenstrukturanalyse. Mittelsab initio-Rechnungen wird versucht zu erklären, weshalb die Reaktion zum Triazol-1-oxid4 und nicht zum erwarteten regioisomeren Triazol-2-oxid3 führt.

Extended oxygen-bridged pyridines and pyrimidines

This paper reports a re-examination of the Biginelli reaction of salicylaldehyde (1) and the synthesis of annelated oxygen-bridged pyrimidines derived therefrom. In addition, prototypes of new fused oxygen-bridged pyridines based on the butenone are described

Crystal structure of 4-hydroxy-2-methyl-5H-naphtho[1', 2':5,6]pyrano [4,3-b]pyridin-5-one: a new heterohelicene

X-ray analysis of the title compound reveals that the molecule relieves steric strain in the fjord region by small adjustments of some bonding parameters rather than any remarkable helical twist. The results show that a (C–)H···N contact shorter than the van der Waals radii of the H and N atoms is an energetically favourable interaction.

4,5-Dihydro-5,5-dimethyl-3H-1,2,4-triazol-3-one 1-Oxide

The title compound, C 4 H 7 N 3 O 2 , formed by oxidation of the parent 4,5-dihydro-5,5-dimethyl-1,2,4-triazol-3-one, consists of a planar five-membered ring with the two O atoms displaced slightly on the same side of the ring. Both the azoxy moiety and the amide N atom are involved in conjugation with the carbonyl group. The molecules in the crystal associate into centrosymmetric double-hydrogen-bonded dimers