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Lycka A.,Research Institute for Organic Syntheses VUOS | Lycka A.,University of Hradec Kralove
Dyes and Pigments | Year: 2017

(1Z)-1-[2-(2-Nitrophenyl)hydrazinylidene]naphthalen-2(1H)-one (1), (4Z)-5-methyl-2-phenyl-4-(2-phenylhydrazinylidene)-2,4-dihydro-3H-pyrazol-3-one (2), (4Z)-5-methyl-4-[2-(2-nitrophenyl)hydrazinylidene]-2-phenyl-2,4-dihydro-3H-pyrazol-3-one (3) and 3,5-dinitro-4-[(2Z)-2-(2-oxonaphthalen-1(2H)-ylidene)hydrazinyl]benzoic acid (4) were prepared and one- and two-dimensional 15N, 13C and 1H NMR spectra were measured and analysed. Results obtained were used in characterization of these compounds from viewpoint of azo-hydrazo tautomerism. All these compounds exist almost completely in appropriate hydrazo forms in dimethyl sulfoxide. Advantages of NMR spectroscopy application in determination of acidic proton positions and azo-hydrazo content determination are discussed. © 2017 Elsevier Ltd


PubMed | University of Pardubice, Institute of Chemical Technology Prague and Research Institute for Organic Syntheses VUOS
Type: Journal Article | Journal: Journal of forensic sciences | Year: 2016

Erythritol tetranitrate (ETN), an ester of nitric acid and erythritol, is a solid crystalline explosive with high explosive performance. Although it has never been used in any industrial or military application, it has become one of the most prepared and misused improvise explosives. In this study, several analytical techniques were explored to facilitate analysis in forensic laboratories. FTIR and Raman spectrometry measurements expand existing data and bring more detailed assignment of bands through the parallel study of erythritol [(15) N4 ] tetranitrate. In the case of powder diffraction, recently published data were verified, and (1) H, (13) C, and (15) N NMR spectra are discussed in detail. The technique of electrospray ionization tandem mass spectrometry was successfully used for the analysis of ETN. Described methods allow fast, versatile, and reliable detection or analysis of samples containing erythritol tetranitrate in forensic laboratories.


Aysha T.,University of Pardubice | Lunak Jr. S.,University of Pardubice | Lycka A.,Research Institute for Organic Syntheses VUOS | Lycka A.,University of Hradec Kralove | Hrdina R.,University of Pardubice
Dyes and Pigments | Year: 2011

Ten azo dyes were prepared by diazotization of a series of electronically different para substituted anilines and subsequent azo coupling of these diazonium salts with ethyl 4,5-dihydro-5-oxo-2-aryl(1H)pyrrole-3-carboxylate as a the coupling component. All of the dyes were confirmed as keto-hydrazone tautomers and were found as a mixtures of E- and Z-isomers with respect to the exocyclic CN bond by 1H-NMR spectroscopy. The absorption spectra are all similar irrespective of substituent and solvent. By comparison the fluorescence is strongly dependent on the electronic character of the substituents. All compounds fluoresce in a low temperature solvent glass and in the solid state and only the 4-cyanophenyl and 4-nitrophenyl derivatives show fluorescence in solution at room temperature. The spectroscopic behavior is explained in terms of competition between E/Z isomerization and fluorescence after excitation. © 2011 Elsevier Ltd. All rights reserved.


Lycka A.,Research Institute for Organic Syntheses VUOS | Lycka A.,University of Hradec Kralove | Lunak Jr. S.,University of Pardubice | Aysha T.,University of Pardubice | And 2 more authors.
Tetrahedron Letters | Year: 2010

15N-Labelled ethyl 5-oxo-2-phenyl-4-(2-phenylhydrazono)-4,5-dihydro-1H-pyrrole-3-carboxylate was synthesized by azo-coupling of diazotized aniline (using Na15NO2, 99% 15N) with ethyl 4,5-dihydro-5-oxo-2-phenyl-(1H)-pyrrole-3-carboxylate. The product was formed as a tautomeric hydrazone mixture as confirmed by 13C and 15N chemical shifts, and was obtained as a mixture of E and Z isomers according to nJ(15N, 13C). A comparison of the 1H NMR data with GIAO DFT calculations enabled determination of the configuration of the carboxy ester group in both isomers. © 2010 Elsevier Ltd. All rights reserved.


Musil T.,University of Pardubice | Matyas R.,University of Pardubice | Lycka A.,Research Institute for Organic Syntheses VUOS | Lycka A.,University of Hradec Kralove | Ruzicka A.,University of Pardubice
Propellants, Explosives, Pyrotechnics | Year: 2012

4,6-Diazido-N-nitro-1,3,5-triazine-2-amine (DANT) was prepared with a 35% yield from cyanuric chloride in a three step process. DANT was characterized by IR and NMR spectroscopy ( 1H, 13C, 15N), single-crystal X-ray diffraction, and DTA. The crystal density of DANT is 1.849 g cm -3. The cyclization of one azido group and one nitrogen atom of the triazine group giving tetrazole was observed for DANT in a dimethyl sulfoxide solution using NMR spectroscopy. An equilibrium exists between the original DANT molecule and its cyclic form at a ratio of 7:3. The sensitivity of DANT to impact is between that for PETN and RDX, sensitivity to friction is between that for lead azide and PETN, and sensitivity to electric discharge is about the same as for PETN. DANT's heat of combustion is 2060 kJ mol -1. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Matyas R.,University of Pardubice | Jirasko R.,University of Pardubice | Lycka A.,Research Institute for Organic Syntheses VUOS | Pachmaa J.,University of Hradec Kralove
Propellants, Explosives, Pyrotechnics | Year: 2011

The existence of two new types of chloroderivates of cyclic acetone peroxides - 3-(chloromethyl)-3,6,6,9,9-pentamethyl-1,2,4,5,7,8-hexoxonane and 3,6-bis(chloromethyl)-3,6,9,9-tetramethyl-1,2,4,5,7,8-hexoxonane was proved by HPLC/MS/MS and NMR in the reaction products when acetone and hydrogen peroxide are mixed in the presence of excess hydrochloric acid (molar ratio hydrochloric acid to acetone nc/na=2.5). The details of analysis, and the conditions under which these asymmetric chloroderivates of cyclic peroxides form, are described. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Jalovy Z.,University of Pardubice | Ek S.,Swedish Defence Research Agency | Ottis J.,University of Pardubice | Dudek K.,Explosia a.s. | And 3 more authors.
Journal of Energetic Materials | Year: 2013

A process for the preparation of 1,1-diamino-2,2-dinitroethene suitable for scale-up was developed. The crucial features to allow scalability and enhance the process safety were the improved synthesis of 2-methoxy-2-methylimidazolidine-4,5-dione and its conversion into 2-hydroxy-2-methylimidazolidine-4,5-dione, which is a new intermediate in the synthesis of 1,1-diamino-2,2-dinitroethene. Its nitration produced 2-(dinitromethylidene)-imidazolidine-4,5-dione, whose hydrolysis into 1,1-diamino-2,2-dinitroethene was further improved. The use of trifluoroacetic acid to remove sulfuric acid prior to hydrolysis is no longer required. The described procedure yields no hazardous intermediates such as dinitromethane or 2-(dinitromethylidene)-5,5-dinitrodihydropyrimidine-4,6(1H,5H)-dione. Thus, the process safety was enhanced in comparison with the commercial production process starting from 2-methylpyrimidine-4,6-dione. © 2013 Copyright Swedish Defence Research Agency (FOI).


Mrkvika V.,Tomas Bata University in Zlin | Lycka A.,Research Institute for Organic Syntheses VUOS | Rudolf O.,Tomas Bata University in Zlin | Klasek A.,Tomas Bata University in Zlin
Tetrahedron | Year: 2010

3-Amino-1H,3H-quinoline-2,4-diones react with thiourea or potassium thiocyanate in boiling acetic acid to give novel 2,3-dihydro-3-thioxoimidazo[1, 5-c]quinazolin-5(6H)-ones in high yields. However, if the starting compounds are substituted with a benzyl group at position 3, a C-debenzylation proceeds to give 2,3-dihydro-2-thioxo-1H-imidazo[4,5-c]quinolin-4(5H)-ones. According to a proposed reaction mechanism, a molecular rearrangement of the primarily formed mono-substituted thiourea takes place. All compounds were characterized by 1H, 13C and 15N NMR and IR spectroscopy as well as by mass spectrometry. © 2010 Elsevier Ltd. All rights reserved.


Chlupaty T.,University of Pardubice | Padelkova Z.,University of Pardubice | Lyka A.,Research Institute for Organic Syntheses VUOS | Brus J.,Czech Institute of Macromolecular Chemical | Ruika A.,University of Pardubice
Dalton Transactions | Year: 2012

The new class of homo- and heteroleptic n-butyl-N,N′-disubstituted amidinato group 14 metal(ii) complexes were prepared by salt elimination from starting lithium amidinates and metal(ii) chlorides both in stoichiometric ratio 2:1 and 1:1, respectively. The target amidinates contain less bulky isopropyl or cyclohexyl as well as a sterically demanding aromatic substituent. Desired 1:1 Pb(ii) complexes are not accessible by the described procedure. Ligand transfer from Pb to Sn is taking place if homoleptic Pb(ii) compounds are reacted with SnCl 2. Prepared tetrylenes were characterized by 1H, 13C, 119Sn and 207Pb NMR spectroscopy in C 6D 6 or THF-d 8. X-Ray diffraction studies of one heteroleptic Ge(ii) monomeric where the coordination polyhedron of the three coordinated germanium atoms is a trigonal pyramid, two different dimeric structures of heteroleptic Sn(ii) complexes, one amidine hydroiodide byproduct and the oxidation product of the heteroleptic chloro Sn(ii) amidinate as a tetranuclear species with two Sn(iv) and two Sn(ii) atoms in central Sn 2O 2 planar ring were performed on appropriate single crystals. The dimer of one of the heteroleptic stannylenes reveals a new type of monomeric units connection, weak Sn-Cl contact and an interaction of the tin atom with delocalized N-C(C)-N system of the amidinato ligand of the second molecule. © The Royal Society of Chemistry 2012.


Chlupaty T.,University of Pardubice | Padelkova Z.,University of Pardubice | Lycka A.,Research Institute for Organic Syntheses VUOS | Ruzicka A.,University of Pardubice
Journal of Organometallic Chemistry | Year: 2011

Lithium n-butyl amidinates (formally lithium salts of N',N-disubstituted amidoimides of pentanoic acid) with various substituents were prepared and characterized in solution by 1H, 7Li, 13C and 15N NMR spectra parameters in C6D6, THF-d 8 and Et2O-d10. The characteristic spectral parameters were compared with parent carbodiimides and amidines prepared by hydrolysis, where large solvent effects were described. Five of studied compounds were studied by X-ray diffraction techniques in the solid state. Lithium n-butyl amidinates containing less bulky substituents like isopropyl or cyclohexyl crystallize with Et2O or THF as centrosymmetric dimers with mutually parallel amidinate moieties. The lithium N,N'-bis[2,6-di(propan-2- yl)phenyl]n-butylamidinate crystallizes from Et2O solution as an asymmetric dimer. The first unit is composed by one ligand coordinated to one of lithium atoms. The lithium atom is also coordinated by one of the nitrogen atoms of the second ligand. The second nitrogen atom of the same ligand is coordinated to the second lithium atom which is also connected to the Et 2O molecule and the aromatic ring of the ligand in a η3-fashion. The same compound crystallizes from the THF solution as a monomeric bis-tetrahydrofuranate. © 2011 Elsevier B.V. All rights reserved.

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