Jerzy T. Wróbel

The effect of verapamil on intestinal calcium transport.

Verapamil (1.5 mM) completely inhibits active calcium transport by everted rat duodenum sacs and depresses oxygen consumption by duodenal rings. Increasing the Ca2+ concentration in the incubation medium from 0.4 mM 5.0 mM reverses the inhibition of oxygen consumption by verapamil but is without effect on the extent of inhibition of calcium active transport.

Sex-dependent composition of cuticular hydrocarbons of the colorado beetle, Leptinotarsa decemlineata say

Abstract 1. 1. Qualitative and quantitative investigation of epicuticular and internal hydrocarbons of Colorado beetles of winter generation were performed. 2. 2. Quantitative compositional differences for sexes were found. 3. 3. Females contain more branched methylalkanes whose tentative structure was identified as either tetramethylhentriacontane or trimethyltritriacontane or a mixture of both. 4. 4. Compositional studies of potato leaves were also done. A prominent component of leaf waxes, 2-methyltricontane, was also found in cuticular hydrocarbons of both sexes as one of the most abundant compounds.

Sulphoxides of thiobinupharidine thiohemiaminals from Nuphar lutea

Abstract From the rhizomes of Nuphar lutea four new alkaloids were isolated. Their structures were established as syn-6-hydroxythiobinupharidine sulphoxide, syn-6′-hydroxythiobinupharidine sulphoxide, syn-6,6′-dihydroxy thiobinupharidine sulphoxide and anti-thiobinupharidine sulphoxide.

Cuticular Hydrocarbons of the Colorado Beetle Leptinotarsa decemlineata say

Abstract The cuticular hydrocarbons of the Colorado beetle Leptinotarsa decemlineata say consist of 2-methylalkanes, internally branched monomethylalkanes, dimethyl-, trimethyl-and tetramethyl-alkanes. The hydrocarbons differ from those of most of the other insects so far investigated. The major components were found to be the dim ethyl branched alkanes, 2,6-and/or 7,22-dimethyl-octacosane and the tetram ethylalkane, 3,10,16,23-tetram ethyltritriacontane. The hydrocarbons identified are members of homologous series which differ by two m ethylene groups. The identification of hydrocarbons was achieved by mass spectrom etry and gas chromatographic determination of Kovats retention indices on two high efficiency capillary columns coated with Dexsil 300 and OV-1.

Nuphacristine—an alkaloid from Nuphar luteum

Abstract From the rhizomes of Nuphar luteum a new C 15 alkaloid, nuphacristine, has been isolated. The structure and stereochemistry of nuphacristine have been established on the basis of spectral analysis and chemical transformations.

Methiodides of nuphar alkaloids: Part I. Studies on stereochemistry by carbon-13 nuclear magnetic resonance spectra of some thiospirane C30 and C15 methiodides

Abstract The 13 C NMR spectra of deoxynupharidine, 7-epideoxynupharidine and thiobinupharidine methiodides have been studied and the correlations between the stereochemistry of these compounds and corresponding chemical shifts are described. Quaternization of the nitrogen causes no steric changes in the trans -quinolizidine system of 7-epideoxynupharidine, whereas deoxynupharidine methiodide has a transformed quinolizidine system with cis ring fusion. Quaternization of thiobinupharidine with methyl iodide results in two isomeric monomethiodides which have been characterized as A′-B′- trans and AB- trans isomers of quaternary salts.

Analysis of exoskeleton triglycerides ofLeptinotarsa decemlineata say

The exoskeleton triglyceride fraction isolated from the Colorado beetle,Leptinotarsa decemlineata Say, was studied. Analysis of the hydrolysis products and direct capillary column gas chromatography showed that, apart from triglycerides, the fraction contained no diol lipids. The composition of the natural triacylglccerol mixture was assessed by gas chromatography and by field desorption and electron impact mass spectrometry. Triglycerides isolated from the Colorado beetle are typical glycerol triesters, with long chain (mainly oleic or palmitic) fatty acids. The structures of two major components (91%), i.e., trioleoyl glycerol and 1,2-dioleoyl-3-palmitoyl glycerol, were determined.

Methiodides of nuphar alkaloids: Part III. Studies on trans—cis transformation of quinolizidine system in thiospiro C30 alkaloids methiodides by 13C-NMR spectroscopy

Abstract The 13 C-NMR spectra of two new monomethiodides isolated from a reaction mixture obtained as a result of quaternisation of thiobinupharidine are reported. It has been established that the quaternisation causes conformational changes of N -substituted quinolizidine rings resulting in transformation of a trans form into a cis one. The structure and stereochemistry of products obtained have been determined by 13 C-NMR spectra. For two monomethiodides in question, the structures of N + 5 ′ − C H 3 cis quinolizidine (A′B′) or N + 5 − C H 3 cis quinolizidine (AB) were assigned.

The stereochemistry of natural thionuphlutine sulfoxides isolated from nuphar luteum

Abstract The combined application of the three research techniques (ASIS, LIS and the S-O bond anisotropy-induced PMR shift analysis) helped in the assignment of the sulfinyl bond configuration in natural isomeric thionuphlutine (TNF) sulfoxides. As in the NTBN S-oxides the more polar TNF S-oxide, 2 , was assigned the beta configuration, and the less polar, 3 , the alpha configuration.

The structure of lanthanide complexes with five membered sulfones and the specific benzene solvation

Abstract By means of a computer program based on the pseudo-contact equation, the structures of lanthanide complexes with five-membered sulfones have been established. The compounds are 1:1 bidentate complexes with the axis of complexation nearly parallel to the bisecting line of the O-S-O angle, and with the lanthanide position being at an average distance of 2.4 A from both oxygen atoms. The Ledal model, which assumes the specific benzene solvation, has been proposed as an adequate model for molecules with planar ring structure, and the distance between the benzene and solute along the preferential axis of complexation has been established as ~ 3.0 A. The most probable conformation of the ring was taken into account because the accuracy of location of the lanthanide or benzene molecule in these complexes depends mainly on the correct model of the molecule assumed. Detailed analysis of the Eu(fod),-induced shifts in the PMR spectrum of NTBN sulfone confirmed the advanced structure of the complexes of five-membered ring sulfones with the lanthanide shift reagents.