Polysulfonylamine. XVII. Darstellung und Röntgenstrukturanalyse von Dimesylamin-Dimethylsulfoxid (1/1)

Polysulfonyl Amines. XVII. Preparation and X-Ray Crystal Structure Determination of Dimesylamine-Dimethyl Sulfoxide (1/1) The solubility of dimesylamine in dichloromethane is largely enhanced by relatively small amounts of dimethyl sulfoxide. From an equimolar solution of the two components in CH₂Cl₂ at ?30°C, a solid addition compound (CH₃SO₂)₂NH · OS(CH₃)₂ ( 1 ), m.p. 53°C, was obtained. 1 crystallizes in the triclinic space group P1 . The atomic arrangements of the two components are similar to those of (CH₃SO₂)₂NH · OH₂ and uncomplexed OS(CH₃)₂, respectively. A short NH…?O hydrogen bond [N…?O 262.5(5) pm] connects the dimesylamine molecule with the dimethyl sulfoxide molecule.     

ETUDE DE LA FRAGMENTATION DE N-ARYL ET DE N-ALKYL AMINOCETONES EN SPECTROMETRIE DE MASSE

A Comparison of the chemical ionisation and elctron-impact mass spectra of alkyl and aryl aminoketones has bee carried out. This has revealed the particular stabilization of the N-aryl grops in all cases.     

Pyridazino[3,4-b]quinoxalines and their reduced derivatives. Preparation and structure

The reaction of o-phenylenediamine with a β-ketoacid, leads in most cases to quinoxalinones. Their structure has been determined as well as that of their corresponding hydrazones. The reaction of hydrazine with these quinoxalinones gives dihydropyridazino[3,4-b]quinoxalines, the structure of which has been ascertained. It has been shown that among the six possible formulas, the only 1,2-dihydro structure fits with the spectroscopic data. On the contrary, N-substituted o-phenylenediamines lead to 2,10-dihydro derivatives. The electrochemical behavior of the 2,10-dihydro-10-methyl-3-phenylpyridazino[3,4-b]quinoxaline has been investigated. It has also been shown that the 3,4,6-trichloropyridazine reacts with o-phenylenediamines to give 5,10-dihydropyridazino[3,4-b]quinoxalines. These compounds can be oxidized to give the new heterocycle pyridazino[3,4-b]quinoxaline.     

Ammonia chemical ionization mass spectrometry of alcohols: Structural,stereochemical, molecular-size and temperature effects

Ammonia chemical ionization (CI) mass spectra of various open-chain, cyclic and unsaturated C₅- to C₁₀-alcohols were obtained at source temperatures ranging from 60° to 250°C. The reactivity of the ammonia adduct ion MNH and its fragmentation channels are characteristic for substrate structure. Although strongly temperature-dependent, the spectra give nevertheless information on the OH-group environment as well as on the C-skeleton at any source temperature. Primary, secondary and tertiary alcohols as well as allylic and simple olefinic alcohols can be distinguished by their spectra, which show ammonium adduct ions [MNH₄]⁺, adduct dehydrogenation ions [MNH₄-H₂], ammonium substitution ions [MNH₄-H₂O]⁺ and [M-OH]⁺-ions as the main characteristic peaks. Moreover, konfigurational assignments of stereoisomeric alcohols are possible for larger substrate-size and source-temperature ranges than with isobutane CI mass spectrometry. Homologous M NH-ions show molecular-size control of fragmentation and linear MNH-ions are less stable than branched isomers due to incomplete energy randomization.     

Polysulfonylamine. CLXIII [1] Kristallstrukturen von Metall‐di(methansulfonyl)amiden. 12 [1] Das orthorhombische Doppelsalz Na2Cs2[(CH3SO2)2N]4·3H2O: Ein dreidimensionales Koordinationspolymer aus (Caesium‐Anion‐Wasser)‐Schichten und intercalierten Natriumionen

Polysulfonylamines. CLXIII. Crystal Structures of Metal Di(methanesulfonyl)amides. 12. The Orthorhombic Double Salt Na₂Cs₂[(CH₃SO₂)₂N]₄·3H₂O: A Three‐Dimensional Coordination Polymer Built up from Cesium‐Anion‐Water Layers and Intercalated Sodium Ions The packing arrangement of the three‐dimensional coordination polymer Na₂Cs₂[(MeSO₂)₂N]₄·3H₂O (orthorhombic, space group Pna2₁, Z′ = 1) is in some respects similar to that of the previously reported sodium‐potassium double salt Na₂K₂[(MeSO₂)₂N]₄·4H₂O (tetragonal, P4₃2₁2, Z′ = 1/2). In the present structure, four multidentately coordinating independent anions, three independent aquo ligands and two types of cesium cation form monolayer substructures that are associated in pairs to form double layers via a Cs(1)—H₂O—Cs(2) motif, thus conferring upon each Cs⁺ an irregular O₈N₂ environment drawn from two N, O‐chelating anions, two O, O‐chelating anions and two water molecules. Half of the sodium ions occupy pseudo‐inversion centres situated between the double layers and have an octahedral O₆ coordination built up from four anions and two water molecules, whereas the remaining Na⁺ are intercalated within the double layers in a square‐pyramidal and pseudo‐C₂ symmetric O₅ environment provided by four anions and the water molecule of the Cs—H₂O—Cs motif. The net effect is that each of the four independent anions forms bonds to two Cs⁺ and two Na⁺, two independent water molecules are involved in Cs—H₂O—Na motifs, and the third water molecule acts as a μ₃‐bridging ligand for two Cs⁺ and one Na⁺. The crystal cohesion is reinforced by a three‐dimensional network of conventional O—H···O=S and weak C—H···O=S/N hydrogen bonds.     

Etude par spectrométrie de masse de la fragmentation du désoxy-3-di-O-isopropylidène-1,2: 5,6-méthylidène-3-α-D-hexofurannose et de quelques analogues substitués en C(3′)

Electron Impact Mass Spectrometry of the 3-Desoxy-1,2: 5,6-di-O-isopropylidene-3-methylidene-δ-D -hexofuranose and Some C(3′)-Substituted Analogues The mass spectra of the 3-desoxy-1,2:5, 6-di-O-isopropylidene-3-methylidene- α-D -ribo-hexofuranose and of some C(3′)-mono- and -disubstituted derivatives have been investigated. Deuterium labelled molecules allow fragmentation modes to be proposed.     

Synthesis of original benzo[g]quinoxaline‐5,10‐diones by bis‐SRN1 methodology

A new heterocyclic bioreductive bis‐alkylating agent, 2,3‐bis(chloromethyl)benzo[g]quinoxaline‐5,10‐dione, was prepared in a four‐steps synthesis. It was shown to react under electron transfer conditions with 2‐nitropropane anion by an bis‐S_RN1 mechanism to give three C‐alkylation products in excellent yields. Extension of this bis‐S_RN1 reaction to various nitronate or malonate anions and S‐centered anions led to a new class of potentially active benzo[g]quinoxaline‐5,10‐dione derivatives.     

Acetylenic and diacetylenic liquid-crystalline monomers: towards ordered conjugated polymers

Abstract

Acetylenic and diacetylenic mesomorphic monomers have been prepared in order to obtain long conjugated polymers able to give high non-linear optical hyperpolarizabilities. Here we report the synthesis of such monomers incorporating cholesteryl and methoxybiphenyl groups; their structural and thermal behaviour are described. The occurrence of mesophases in the acetylenic and diacetylenic derivatives is discussed as a function of the spacer length and of the size of the mesogen moiety. The diacetylenic derivatives containing the methoxybiphenyl groups do not exhibit any liquid-crystalline behaviour but are able to polymerize under U.V. radiation.     

A new DMAP-catalyzed and microwave-assisted approach for introducing heteroarylamino substituents at position-4 of the quinazoline ring

We report herein a new methodology for synthesizing quinazoline derivatives bearing a heteroarylamino moiety at position-4 of the quinazoline ring. As an alternative to the Buchwald–Hartwig cross-coupling reaction, which appears, until now, as the only efficient way to react 4-chloroquinazolines with numerous amino nitrogen-containing heterocycles displaying poor nucleophilicity, we developed a DMAP-catalyzed reaction involving microwave irradiation. Optimization of the reaction conditions led to the use of 30 mol % of DMAP in toluene, using a monomode microwave reactor and sealed vials. Moreover, the S_NAr reaction intermediate salt was isolated and fully characterized. Finally, the procedure was extended to two different 2-substituted-quinazoline series and also to various anilines, demonstrating that this approach was a general efficient way to access to such 4-substituted quinazoline scaffolds of high pharmaceutical interest.