C. Kruk

Cis-cis-trans-bicadinane, a novel member of an uncommon triterpane family isolated from crude oils

Cis-cis-trans-bicadinane, an uncommon triterpane present in South East Asian crude oils has been isolated and its structure has been revealed with NMR-spectroscopic methods.

Intramolecular redox systems related to NAD/NADH, part 1. A kinetic study of intramolecular hydride exchange by 1-H-spin saturation transfer

Abstract Intramolecular hydride transfer between 1,4-dihydronicotinamide and nicotinamidium moieties connected by a polymethylene chain −(CH 2 ) n− is studied by the 1 H-spin saturation transfer technique. For n=3 an effective molarity EM=210 is found for the 4,4′-hydride exchange which is not accompanied by the competing 4,6′ and solvent exchange processes reported in related intermolecular reactions.

5-Exo-Trig vs 6-Endo-Trig α-acyliminium ion-olefin cyclisations stereoselective synthesis of 7-(1-formyloxy-pent-1-yl)-1-aza-4-oxa-spiro[4.5]decane-2-ones

Abstract The two C 6 , C 7 trans substituted title compounds have been synthesized via stereoselective 5- Exo -Trig ringclosures starting from (E)-resp. (Z)-4-nonene-1-yl bromide and 3,5-morpholinedione.

New Crinine-Type Alkaloids From Pancratium. Maritimum L. Growing In Turkey

Abstract Pancratium maritimum L. of Turkish origin has yielded two new crinine-type alkaloids, (-)-3β, 11α-dihroxy-1,2-dehydrocrinane (1) and (-)-8-Hydroxy-9-methoxycrinine (2). the alkaloids were separated using the combination of flash chromatography and preparative tic and purified by crystallization. Their structures have been determined by spectroscopic studies.

Photocycloaddition of ethylvinylether and cyclopentene to 3.5-dimethylanisole

Abstract Photocycloadition of ethylvinylether and cyclopentene to 3,5-dimethylanisole yields derivatives of 1-methoxy-2, 4-dimethyltricyclo [3.3.0.0 2,8 ]oct-3-ene in which the substituents at positions 6 and/or 7 are endo. Structural proofs are based on 250 MHz 1 H and 62.9 MHz 13 C NMR spectra.