Biomedical subjects

Roman Dembinski

Publications and source records attributed to Roman Dembinski.

7 recordsLinked to original sources

PubMed2006

Thionation using fluorous Lawesson's reagent.

[reaction: see text] Thionation of amides, 1,4-diketones, N-(2-oxoalkyl)amides, N,N'-acylhydrazines, and acyl-protected uridines with the use of a fluorous analogue of the Lawesson's reagent leads to thioamides, thiophenes, 1,3-thiazoles, 1,3,4-thiadiazoles, and acyl-protected 4-thiouridines. The isolation of the final products in high yields is achieved in most cases by a simple filtration (fluorous solid-phase extraction).

Combinatorial Chemistry Techniques↗

PubMed2005

5-Endo-dig electrophilic cyclization of 1,4-disubstituted but-3-yn-1-ones: regiocontrolled synthesis of 2,5-disubstituted 3-bromo- and 3-iodofurans.

[reaction: see text] 5-Endo-dig electrophilic cyclization of 1,4-diaryl but-3-yn-1-ones with N-bromosuccinimide or N-iodosuccinimide/acetone and iodine monochloride/CH(2)Cl(2), at room temperature, in the absence of base, provides 3-halo-2,5-diarylfurans with excellent regiocontrol and high yields (81-94%).

Journal Article↗

PubMed2005

NMR conformational analysis of p-tolyl furanopyrimidine 2'-deoxyribonucleoside and crystal structure of its 3',5'-di-O-acetyl derivative.

The conformation of a representative molecule of a new, potent class of antiviral-active modified nucleosides is determined. A bicyclic nucleoside, 3-(2'-deoxy-beta-D-ribofuranosyl)-6-(4-methylphenyl)-2,3-dihydrofuro[2,3-d]pyrimidin-2-one, shows C2'-endo and C3'-endo ribose conformations in solution (63:37, 37 degrees C; DMSO-d6), as determined by 1H NMR studies. The crystal structure of a 3',5'-di-O-acetyl-protected derivative (monoclinic, P21, a/b/c= 6.666(1)/12.225(1)/24.676(2) A, beta=90.24(1) degrees , Z=4) shows exclusively C2'-endo deoxyribose puckering. The base is found in the anti position both in solution and in crystalline form.

Crystallography, X-Ray↗

PubMed2003

5-Endo-dig electrophilic cyclization of alpha-alkynyl carbonyl compounds: synthesis of novel bicyclic 5-iodo- and 5-bromofuranopyrimidine nucleosides.

5-Endo-dig electrophilic cyclization of 5-alkynyl-2'-deoxyuridines with N-iodosuccinimide or N-bromosuccinimide in acetone at room temperature gives 3-(2'-deoxy-beta-D-ribofuranosyl)-5-halo-2,3-dihydrofuro[2,3-d]pyrimidin-2-ones that usually precipitate from the reaction mixture (86-74%).

Bridged Bicyclo Compounds↗

PubMed2002

Fluorous, chromatography-free Mitsunobu reaction.

[formula: see text] The reaction of secondary and primary alcohols with highly fluorinated 3,4,5-tris(5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,12-heptadecafluorododecan- 1-yloxy)benzoic acid in the presence of Ph3P and DIAD in THF at room temperature (fluorous Mitsunobu) resulted in a simple, chromatography-free isolation protocol with excellent yields (83-96%).

Journal Article↗

PubMed2002

Synthesis of dicobalt hexacarbonyl 5-p-tolylethynyl-2'-deoxyuridine.

Reactions of 5-p-tolylethynyl-2'-deoxyuridine and 3',5'-di-O-acetyl-5-p-tolylethynyl-2'-deoxyuridine with Co2(CO)8 in THF gave 5-p-tolC2[CO2(CO)6]-2'-deoxyuridine and 3',5'-di-O-acetyl-5-p-tolC2[CO2(CO)6]-2'-deoxyuridine (92 and 66%).

Cyclization↗

PubMed2002

Isolation and structural elucidation of 3,4',5,7-tetraacetyl quercetin from Adina cordifolia (Karam ki Gaach).

3,4',5,7-tetraacetyl quercetin (1) was isolated from the heartwood of Adina cordifolia. The structure was elucidated on the basis of spectral evidence.

Humans↗