Zbigniew Wróbel

SILANE-MEDIATED DIRECT CONDENSATION OF NITROARENES WITH CINNAMYL-TYPE SULFONES. THE WAY TO 2-ARYL-4-X-QUINOLINES AND THEIR HETERO ANALOGS

Abstract DBU/silane mediated double condensation of nitroarenes with cinnamyl-type sulfones proceeds smoothly to yield 2-aryl-4-arylsulfonyl quinolines and their hetero analogs. Arylsulfonyl group can be easily replaced by different nucleophiles.

Synthesis of 1-hydroxyindoles and indoles from ortho-nitroarylethanes

Cyclization of substituted ortho-nitroarylethanes to 1-hydroxyindoles and their further reduction to indoles is described. The mechanism of cyclization is discussed.

Synthesis of 4-Arylsulfonylquinolines by Double Condensation of Allyl Aryl Sulfones with Nitroarenes

Allyl aryl sulfones 2 react with aryl nitrocompounds 1 in a DBU/MgCl2 system giving the 4-arylsulfonyl quinolines 3. Some mechanistic aspects of the reaction are discussed. Application of this reaction to the formal total synthesis of the natural product (−)Eupolauramine is described.

Oxozinc carboxylates: a predesigned platform for modelling prototypical Zn-MOFs' reactivity toward water and donor solvents

Two unique adducts of an oxozinc carboxylate cluster with H(2)O and THF were isolated and structurally characterized, [Zn(4)(μ(4)-O)(O(2)CR)(6)(H(2)O)(THF)]·2(THF) and [Zn(4)(μ(4)-O)(O(2)CR)(6)(THF)(3)] (where R = benzoate and R = 9-antracenecarboxylate anion). The study shows that the zinc centers of the Zn(4)O core can easily form unique coordination environments without breaking of the Zn-O(carboxylate) bonds.

New concept in synthesis of fused six-membered nitrogen heterocycles. Silane-Mediated direct condensation of nitroarenes with allylic carbanions

Abstract Six-membered nitrogen containing ring was constructed via double condensation of allylic CH-acids with nitoarenes. The reactions proceed with high regioselectivity. Mechanism of the transformation was discussed.

Transformations of o-nitroarylallyl carbanions. Synthesis of quinoline N-oxides and N-hydroxyindoles. ☆

Abstract Nitriles and esters of 2-( o -nitroaryl)crotonic acids are converted under basic conditions into substituted quinoline N-oxides, N-hydroxyindoles and N-hydroxy-2-hydroxymethyl indoles. Factors governing the reaction course and mechanistic pathways are discussed.

Towards Organized Hybrid Nanomaterials at the Air/Water Interface Based on Liquid-Crystal/ZnO Nanocrystals

The ability to self-assemble nanosized ligand-stabilized metal oxide or semiconductor materials offers an intriguing route to engineer nanomaterials with new tailored properties from the disparate components. We describe a novel one-pot two-step organometallic approach to prepare ZnO nanocrystals (NCs) coated with deprotonated 4-(dodecyloxy)benzoic acid (i.e., an X-type liquid-crystalline ligand) as a model LC system (termed ZnO-LC1 NCs). Langmuir and Langmuir-Blodgett films of the resulting hybrids are investigated. The observed behavior of the ZnO NCs at the air/water interface is rationalized by invoking a ZnO-interdigitation process mediated by the anchored liquid-crystalline shell. The ordered superstructures form according to mechanism based on a ZnO-interdigitation process mediated by liquid crystals (termed ZIP-LC). The external and directed force applied upon compression at the air/water interface and the packing of the ligands that stabilize the ZnO cores drives the formation of nanorods of ordered internal structure. To study the process in detail, we follow a nontraditional protocol of thin-film investigation. We collect the films from the air/water interface in powder form (ZnO-LC1 LB), resuspend the powder in organic solvents and utilize otherwise unavailable experimental techniques. The structural and physical properties of the resulting superlattices were studied by using electron microscopy, atomic force microscopy, X-ray studies, dynamic light scattering, thermogravimetric analysis, UV/Vis absorption, and photoluminescence spectroscopy.

Conversion of 3-nitroanilines into tricyclic systems: 1H-1-alkyl-8-X-2,2-dioxoisothiazolo[5,4,3-d,e]quinolines

Abstract The route leading to the tricyclic 2,2-dioxoisothiazolo[5,4,3- d , e ]quinolines from 3-nitroanilines has been described. The scope and limitation factors as well as some mechanistic features are discussed.

Photoactive Langmuir–Blodgett, Freely Suspended and Free Standing Films of Carboxylate Ligand-Coated ZnO Nanocrystals

A new possibility for the formation of macroscopic and photoactive structures from zinc oxide nanocrystals is described. Photoactive freely suspended and free-standing films of macroscopic area (up to few square millimeters) and submicrometer thickness (up to several hundreds of nanometers) composed of carboxylate ligand-coated zinc oxide nanocrystallites (RCO2-ZnO NCs) of diameter less than 5 nm are prepared according to a modified Langmuir-Schaefer method. First, the suspension of RCO2-ZnO NCs is applied onto the air/water interface. Upon compression, the films become turbid and elastic. The integrity of such structures is ensured by interdigitation of ligands stabilizing ZnO NCs. Great elasticity allows transfer of the films onto a metal frame as a freely suspended film. Such membranes are afterward extracted from the supporting frame to form free-standing films of macroscopic area. Because the integrity of the films is maintained by ligands, no abolishment of quantum confinement occurs, and films retain spectroscopic properties of initial RCO2-ZnO NCs. The mechanism of formation of thin films of RCO2-ZnO NCs at the air/water interface is discussed in detail.

Synthesis of 1H-1-alkyl-8-X-2,2-dioxoisothiazolo[5,4,3-d,e]-quinolines via tandem cyclization of N-alkyl-N-(2-X-5-nitrophenyl)prop-2-enyl sulfonamides

Abstract Tandem five- and six-membered ring closure reactions to afford tricyclic sultams from N -alkyl- N -(2-X-5-nitrophenyl) prop-2-enyl sulfonamides is described.