Fluordiazadiphosphetidine, 6. Mitt.Die reaktion von 2,2,2,4,4,4-Hexafluoro-1,3-dimethyl-1,3,2λ5,4λ5-diazadiphosphetidin mit Fluorwasserstoff

Reaction of (CH₃NPF₃)₂ with dry hydrogen fluoride yields CH₃NH₃+PF₆-and the new compound (CH₃NHPF₄)₂.

     

Fluordiazadiphosphetidine, 18. Mitt. Neue zwitterionische Fluordiazadiphosphetidinderivate

The reaction of (CH₃NPF₃)₂ with substituted hydrazines yields a new type of a P/N/P/N ring system by addition of one molecule hydrogenfluorid to the substituted molecule. These betain-like compounds are the first examples of a P/N/P/N ring system with one P-atom in ⁵- and the other in ⁶-conformation.

     

Fluordiazadiphosphetidine, 15. Mitt.: Die Reaktionen von Hexafluordiazadiphosphetidinen mit Fluorwasserstoff

The reaction of fluorodiazadiphosphetidines with dry hydrogenfluoride has been studied thoroughly. Depending on the nature of the substitutents on the nitrogen atom this reaction can take two different courses: a) yielding the octafluoro-1,3,2⁶,4⁶-diazoniadiphosphatetidines¹; b) forming the corresponding amine-phosphoruspentafluoride-adducts, which are enabled for various further reactions. A scheme of possible reactions has been established.

     

Highly Enantioselective Synthesis of Orthogonally Protected (2S)‐2,3‐Diaminopropanoates through Catalytic Phase‐Transfer Aza‐Henry Reaction

The syntheses of enantiomer‐enriched orthogonally protected different (2S)‐2,3‐diaminopropanoates and unnatural furyl‐substituted (tert‐butoxy)carbonyl (Boc) as well as (benzyloxy)carbonyl (Cbz) protected amino acid esters are accomplished by means of an enantioselective aza‐Henry reaction. A key feature of this protocol is organocatalysis as a genesis of chirality to ensure high enantioselectivity.     

Asymmetric Synthesis of Indoline from Achiral Phthalimide Involving Crystallization-Induced Deracemization

Asymmetric synthesis was performed by combining the photochemical reaction of an achiral substrate followed by crystallization-induced deracemization. The results indicated that a fused indoline produced by photochemical intramolecular δ-hydrogen abstraction and cyclization of N-(5-chloro-2-methylphenyl)phthalimide crystallized as a racemic conglomerate. Since this substrate has an aminal skeleton, racemization involving a ring-opening and ring-closing equilibrium process occurred under suitable conditions. Efficient racemization was observed in acetone containing a catalytic base, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). Crystallization-induced dynamic deracemization by Viedma ripening from racemic indoline was performed with an excellent enantioselectivity of 99 % ee. Furthermore, one-pot asymmetric synthesis of the indoline was achieved by the photochemical reaction of achiral phthalimide followed by continuous attrition-enhanced deracemization converging to 99 % ee of enantiomeric crystals. This is the first example of asymmetric expression and amplification by photochemical hydrogen abstraction and crystallization-induced dynamic deracemization.     

Remarks on the detection of aza arenes in airborne particulates

Summary Suspended particulate matter sampled in the ambient air of Duisburg was investigated for the content of aza heterocyclic compounds. The loaded filters were extracted for 10 hours in a soxhlet apparatus. The concentrated extract was shaken with diluted sulphuric acid. The aqueous layer was adjusted to pH 12 with potassium hydroxide and then extracted with dichloromethane. The organic layer was transfered into cyclohexane and columned on alumina. The separated fraction was then examined by means of GC/MS. Quinoline, benzoquinoline, acridine and some of their alkyl derivates as well as azapyrene/fluoranthene were identified, whereas benzo- and dibenzoacridine could not be detected.     

Fe3O4@Propylsilane@Histidine[HSO4‐] magnetic nanocatalysts: Synthesis,characterization and catalytic application for highly efficient synthesis of xanthene derivatives

The surface of Fe₃O₄ magnetic nanoparticles (MNPs) was modified by chloropropylsilane and histidine. The imidazole group of prepared Fe₃O₄@Propylsilane@Histidine MNPs converted to imidazolium hydrogen sulfate group and Fe₃O₄@Propylsilane@Histidine [HSO₄^‐] as a novel environmentally friendly ionic liquid/ magnetite nanoparticle was prepared, successfully. FT‐IR, XRD, SEM and TEM instruments was used to identifiy the histidine ionic liquids/magnetite nanoparticles (HILMNPs). The catalytic activity of synthesized HILMNPs was appraised for the synthesis of 9‐aryl‐1,8‐dioxooctahydroxanthene and spiro[indoline‐3,9′‐xanthene]trione derivatives. The activity of HILMNPs was much better than the other reported heterogeneous and homogeneous catalysts. Furthermore, the prepared catalyst could be separated from the reaction mixture and reused four times without any significant loss in its activity.     

Three Novel Mixed‐ligand Cadmium(II) Sulfonates with Aza‐aromatic Skeltons as Co‐ligands

To survey the influence of aza‐aromatic co‐ligands on the structure of Cadmium(II) sulfonates, three Cd(II) complexes with mixed‐ligand, [Cd^II(ANS)₂(phen)₂] ( 1 ), [Cd^II(ANS)₂(2,2′‐bipy)₂] ( 2 ) and [Cd^II(ANS)₂(4,4′‐bipy)₂]_n ( 3 ) (ANS = 2‐aminonaphthalene‐1‐sulfonate; phen = 1,10‐phenanthroline; 2,2′‐bipy = 2,2′‐bipyridine; 4,4′‐bipy = 4,4′‐bipyridine) were synthesized by hydrothermal methods and structurally characterized by elemental analyses, IR spectra, and single crystal X‐ray diffraction. Of the three complexes, ANS consistently coordinates to Cd²⁺ ion as a monodentate ligand. While phen in 1 and 2,2′‐bipy in 2 act as N,N‐bidentate chelating ligands, leading to the formation of a discrete mononuclear unit; 4,4′‐bipy in 3 bridges two Cd^II atoms in bis‐monodentate fashion to produce a 2‐D layered network, suggesting that the conjugate skeleton and the binding site of the co‐ligands have a moderate effect on molecular structure, crystal stacking pattern, and intramolecular weak interactions. In addition, the three complexes exhibit similar luminescent emissions originate from the transitions between the energy levels of sulfonate anions.     

Cinchona-derived ammonium salts-catalyzed aza Diels-Alder reaction of Danishefsky’s diene with imines

Described is the efficiency of cinchona-derived quaternary ammonium salts as Lewis acid organocatalysts in aza Diels-Alder reaction of Danishefsky’s diene 1 with imines 2 and 16, providing 1,2-dialkyl-2,3-dihydro-4-pyridinones 3 and cyclic dihydropyridones 17, respectively. Among the nine of cinchonidine-derived quaternary ammonium catalysts prepared, N-2′,3′,4′-trifluorobenzyl-O-benzylcinchonidinum bromide (6) exhibited the highest chemical yield (up to 99%). Systematic study on structure-catalytic efficiency relationship revealed that 2′,3′,4′-trifluorobenzyl, quinuclidine, and quinoline moieties are essential.