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Cited by 2 publications
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207 UI-Azlrldine aus Chalkonen und HydroxylaminAus den hochsubstituierten Chalkonen 1 entstehen nicht die nach von Auwers') zu envanenden Dioxime 2 oder Hydroxyamino-oxime 3 unter Verbrauch von zwei Mol Hydroxylamin. Stan dessen wird nur ein Mol Hydroxylamin verbraucht, und es entstehen tram-konfigurierte 2-BenzoylHighly substituted chalcones 1 do not react with two molecules of hydroxylamine affording dioximes 2 or hydroxyamino-oximes 3 as expected according to von Auwers' procedure'): only one molecule of hydroxylmine is consumed leading to trans-configurated 2-benzoyl-3-phenyI-lHaziridines 4.3-phenyl-1H-aziridine 4.Schdnenberger et al.2)3) have reported on cytostatic Pt-complexes of the 1 .2-diamino-l,2-diphenylethane type. Especially meso-1.2-bis-(2,6-dichloro-4-hydroxyphenyl)ethylenediamine-dicNo(II) (5) is of interest as it shows low affmity to the estrogen receptor when compared with the Ptfree ligand, it has, however, an enhanced endocrinological activity.In our f i t paper in this fiel$) we have touched on the conformational flexibility of Pt-complexes of 1,Zdiamino-ethanes in comparison with that of 1,3-diaminopropane-Pt-complexes, prepared according to von Auwers') by reacting chalcones with two molecules of hydroxylamine followed by reduction (Scheme 2 in lit.4)). Here we describe an anomality of von Auwers' procedure:When 0.1 mol of the chalcones 1 -prepared from 2,6-dichloro-x-methoxybenzaldehydes 6 and 2,6-dichloror-xmethoxyacetophenones 7 (which in turn could not be prepared by Friedel-Crafts acylation but were obtained from 6a, 6b with H3CMgI and subsequent oxidation) -were treated in a slightly modified von Auwers-procedure') as described4) with 0.263 mol H2NOH.HCl in water/KOH (Experim. Part and Lit.4)) we obtained ketones which contain one N-atom only. 'H-NMR spectra revealed that transconfigurated aziridines were formed: according to Brois') 3~HccH in cis-aziridines is always greater than that in transaziridines. For cis-aziridines J-values of 5.0 -8. 5 Hz are reported, whilst trans-isomers show 2.0 -6.3 Hz. These data are corroborated by Weber and Lieperf@. In our cases J
207 UI-Azlrldine aus Chalkonen und HydroxylaminAus den hochsubstituierten Chalkonen 1 entstehen nicht die nach von Auwers') zu envanenden Dioxime 2 oder Hydroxyamino-oxime 3 unter Verbrauch von zwei Mol Hydroxylamin. Stan dessen wird nur ein Mol Hydroxylamin verbraucht, und es entstehen tram-konfigurierte 2-BenzoylHighly substituted chalcones 1 do not react with two molecules of hydroxylamine affording dioximes 2 or hydroxyamino-oximes 3 as expected according to von Auwers' procedure'): only one molecule of hydroxylmine is consumed leading to trans-configurated 2-benzoyl-3-phenyI-lHaziridines 4.3-phenyl-1H-aziridine 4.Schdnenberger et al.2)3) have reported on cytostatic Pt-complexes of the 1 .2-diamino-l,2-diphenylethane type. Especially meso-1.2-bis-(2,6-dichloro-4-hydroxyphenyl)ethylenediamine-dicNo(II) (5) is of interest as it shows low affmity to the estrogen receptor when compared with the Ptfree ligand, it has, however, an enhanced endocrinological activity.In our f i t paper in this fiel$) we have touched on the conformational flexibility of Pt-complexes of 1,Zdiamino-ethanes in comparison with that of 1,3-diaminopropane-Pt-complexes, prepared according to von Auwers') by reacting chalcones with two molecules of hydroxylamine followed by reduction (Scheme 2 in lit.4)). Here we describe an anomality of von Auwers' procedure:When 0.1 mol of the chalcones 1 -prepared from 2,6-dichloro-x-methoxybenzaldehydes 6 and 2,6-dichloror-xmethoxyacetophenones 7 (which in turn could not be prepared by Friedel-Crafts acylation but were obtained from 6a, 6b with H3CMgI and subsequent oxidation) -were treated in a slightly modified von Auwers-procedure') as described4) with 0.263 mol H2NOH.HCl in water/KOH (Experim. Part and Lit.4)) we obtained ketones which contain one N-atom only. 'H-NMR spectra revealed that transconfigurated aziridines were formed: according to Brois') 3~HccH in cis-aziridines is always greater than that in transaziridines. For cis-aziridines J-values of 5.0 -8. 5 Hz are reported, whilst trans-isomers show 2.0 -6.3 Hz. These data are corroborated by Weber and Lieperf@. In our cases J
Size Effects on the Unimolecular Fragmentation of their [M + H]+ Ions.The influence of ring-strain energy upon the conformation and chemical properties of cyclic alkanes has extensively been investigated by a variety of experimental approaches (1). Scant systematic studies on azacycloalkanes concern the kinetics of their cyclization processes from the corresponding bromides (2), the assessment of structure-reactivity relationships via nuclear magnetic resonance spectrometry (3), the influence of ring size on their ionization energies (4) and the mass spectra of related compounds, ionized by electron impact (5). We now report a mass spectrometric study aimed at evaluating whether and to what an extent can ring strain influence the unimolecular fragmentation pattern of protonated N-tosylazacycloalkanes (An), with ring size n ranging from 3 to 12.An (n = 3 -12)The compounds, prepared and purified according to previously published procedures (2,6), were directly introduced into the source of a ZAB-2F mass spectrometer (VG-Micromass) kept at 140 "C. Unless otherwise specified, isobutane was employed as the chemical-ionisation reactant gas to ensure mild ionisation of the samples and to keep the excess internal energy of the protonated molecular species as low as possible. The source parameters were 0.4 Torr pressure, as measured with a MKS Baratron type 221-A manometer, 0 V repeller voltage, 1mA emission current and 100 eV electron energy. The spectra, recorded at 8 KV accelerating voltage with a VG-11/250 Data System, show for all the An an intense [M + H]+ peak and negligible (< 10%) intensity of fragment ions. This was taken as an indication that the experimental conditions employed are suited to produce clean protonated N-tosylazacycloalkanes probably retaining the original cyclic structure, and therefore to show possible ring-strain energy effects on their unimolecular fragmentation processes, observable in the field-free regions (FFR) of the i n s t r u m e n t . Both B E and MIKE scans were employed to study the unimolecular decomposition of the [M + HI+ ions occurring respectively in the 1st and in the 2nd FFR . The spectra are reported in Table 1 together with some relevant thermochemical data such as the ring-strain enthalpy of the corresponding cycloalkanes (7). and the available ionization energy values (4). Under the same experimental conditions, ensuring very low fragmentation of the quasi-molecular ions in the source, the MIKE spectra of some open-chain p-toluenesulfonamides, collected for comparison, showed the following peaks [ m/z (I%)]: N-butyl, 172(63); 155 (33); 91(1); 72(3) and N,N-dibutyl, 228(88); 172(1); 155(3); 128(8); N,N-dimethyl 155(8 1); 44( 19).The data show that the [M + H]+ions of N-tosylazacycloalkanes decompose, in the time frame of metastable peak observation, along three main competitive unimolecular channels, common to all ring sizes: 1) rupture of the sulfur-nitrogen bond, to give the CH3-C6H4-S02+ ion (m/z 155) and the neutral amine; 2) ring rupture leading to a common peak at m...
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