Synthesis,structure and cytotoxic activity of 2‐acetyl‐5‐trimethylsilylthiophene(furan) and their oximes

5‐Trimethylsilylderivatives of 2‐acetylthiophene and ‐furan have been regioselectively prepared by a one‐pot procedure from the corresponding 2‐acetylfuran or 2‐acetylthiophene using lithium N‐methylpiperazide (LNMP)–butyllithium–trimethylchlorosilane–water as the sequence of reagents. The ketones obtained were converted to the corresponding oximes. The structure of 2‐acetyl‐5‐trimethylsilylthiophene oxime (E‐isomer) has been studied by X‐ray diffraction. Formation of centrosymmetric dimers by means of H‐bonds has been observed. The intermolecular hydrogen bond O9? H…N8 length is 2.842(5) Å [H…N8 = 1.87 (6) Å, O9? H…N8 = 157(4)°]. Copyright © 2006 John Wiley & Sons, Ltd.     

Sulfones of 7-silyl- and 7-germylcephalosporanates

7-Silyl- and 7-germylcephalosporanates in the form of a mixture of 7a and 7b stereoisomers were prepared by the interaction of hydrosilanes and a hydrogermane^* with sulfones of tert-butyl esters of 7-diazocephalosporanic acid and 7-diazodesacetoxycephalosporanic acid in the presence of rhodium diacetate. Some of the synthesized substances manifest cytotoxic effects in relation to tumor cellsin vitro, and also inhibit the catalytic activity of the enzyme elastase.Generic terms for compounds with the general formula HSiX₃ or HGeX₃-Translator.Latvian Institute of Organic Chemistry, Riga LV-1006, Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1504–1509, November, 1998.     

ERETIC implemented in diffusion-ordered NMR as a diffusion reference: a clarification

Additional information as to the objectives of our previous paper entitled 'ERETIC implemented in diffusion-ordered NMR as a diffusion reference' (Magn. Reson. Chem. 2008, 46, S63) is provided. The need for an optimal instrumental stability for the method proposed to be reliably applicable in view of these objectives is emphasized and illustrated.     

Synthesis and cytotoxicity of pyridine and quinoline oxorhenium(V) complexes with tridentate (NS2, S3)/monodentate (s) coordination*

New oxorhenium complexes with tridentate 3-thia- and 3-methylazapentane-1,5-dithiolate and monodentate pyridine and quinoline derivatives have been synthesized. As a result of investigation of biological activity a high cytotoxicity was found for the synthesized complexes in relation to tumor cells. The specificity of the 2-pyridylthiolato[3-(N-methyl)azapentane-1,5-dithiolato]oxorhenium(V) cytotoxic action towards cells of mouse hepatoma MG-22A on a background of low acute toxicity was established.     

Study on the formation of a supramolecular conjugated graft copolymer in solution

The formation in solution of a supramolecular graft copolymer bearing conjugated blocks is demonstrated using diffusion ordered NMR spectroscopy (DOSY). A tailor‐made poly(3‐(2‐ethylhexyl)thiophene) (P3EHT) with a phenol end group is synthesized. For this purpose, the chain‐growth mechanism of the polymerization of 2‐bromo‐5‐chloromagnesio‐3‐alkylthiophenes in the presence of a Ni(dppp) catalyst (dppp = 1,3‐bis(triphenylphosphino)propane) is exploited, as it enables the use of functionalized initiators to introduce specific end groups. The so‐obtained polythiophene was subsequently mixed in solution with poly(4‐vinylpyridine) (P4VP) to enable phenol‐pyridine hydrogen bonding. The formation of the supramolecular graft copolymer is studied using DOSY‐measurements. Based on the results thereof, the amount of P3EHT attached to the P4VP is calculated and the association constant of the hydrogen bond is estimated. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 804–809     

Synthesis, structure, and cytotoxicity of O-[3-(5-tetrazolyl)propyl]oximes

A two-stage method was developed for the conversion of phenyl-and pyridylaldoximes and ketoximes into the corresponding O-[3-(5-tetrazolyl)propyl]oximes. The structure of the sodium salt of 2-acetylpyridine O-[3-(5-tetrazolyl)propyl]oxime was established X-ray diffraction analysis. This compound was shown to possess a high cytotoxic activity in vitro.     

Spatial structure of 3-acyl-2-methylindole oximes

It has been established on the basis of the results of ¹H and ¹³C NMR, UV, and IR spectroscopy that 3-acyl-2-methylindole oximes each exist in the form of a mixture of two isomers with a predominance of syn-s-trans form. The proportion of the anti form rises (to 25–35%) with an increase in the volume of the alkyl radical in the oxime grouping.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 65–68, January, 1984.     

Synthesis,structure and biological activity of new 6,6‐dimethyl‐2‐oxo‐4‐{2‐[5‐organylsilyl(germyl)]furan(thiophen)‐2‐yl}vinyl‐5,6‐dihydro‐2H‐pyran‐3‐carbonitriles

New 6,6‐dimethyl‐2‐oxo‐4‐{2‐[5‐alkylsilyl(germyl)]furan(thiophen)‐2‐yl}vinyl‐5,6‐dihydro‐2H‐pyran‐3‐carbonitriles (IC₅₀: 1–6 µg ml^?1) have been prepared by the condensation of corresponding silicon‐ and germanium‐containing furyl(thienyl)‐2‐carbaldehydes with 3‐cyano‐4,6,6‐trimethyl‐5,6‐dihydropyran‐2‐one using piperidine acetate as a catalyst. The obtained carbonitriles were identified using NMR (¹H, ¹³C and ²⁹Si) spectroscopy and GC‐MS. The structure of 6,6‐dimethyl‐2‐oxo‐4‐[2‐(5‐trimethylsilyl)thiophen‐2‐yl]‐5,6‐dihydro‐2H‐pyran‐3‐carbonitrile was studied using X‐ray diffractometry. The influences of the heterocycle and the structure of the organoelement substituent on cytotoxicity and on matrix metalloproteinase inhibition have been studied. Copyright © 2015 John Wiley & Sons, Ltd.