Synthetic approaches to multifunctional indenes

The synthesis of multifunctional indenes with at least two different functional groups has not yet been extensively explored. Among the plausible synthetic routes to 3,5-disubstituted indenes bearing two different functional groups, such as the [3-(aminoethyl)inden-5-yl)]amines, a reasonable pathway involves the (5-nitro-3-indenyl)acetamides as key intermediates. Although several multistep synthetic approaches can be applied to obtain these advanced intermediates, we describe herein their preparation by an aldol-type reaction between 5-nitroindan-1-ones and the lithium salt of N,N-disubstituted acetamides, followed immediately by dehydration with acid. This classical condensation process, which is neither simple nor trivial despite its apparent directness, permits an efficient entry to a variety of indene-based molecular modules, which could be adapted to a range of functionalized indanones

Azolium-based systems: application of an anion exchange resin (A- form) method and 1H NMR analysis of the charged-assisted (C<br>H)+·anion hydrogen bonds

The counteranion exchange of quaternary 1,2,3-triazolium salts was examined using a simple method that permitted halide ions to be swap for a variety of anions using an anion exchange resin (A¯ form). The method was applied to 1,2,3-triazolium-based ionic liquids and the iodideto- anion exchange proceeded in excellent to quantitative yields, concomitantly removing halide impurities. Additionally, an anion exchange resin (N3¯ form) was used to obtain the benzyl azide from benzyl halide under mild reaction. Likewise, following a similar protocol, bis(azidomethyl)arenes were also synthesized in excellent yields. The results of a proton NMR spectroscopic study of simple azolium-based ion pairs are discussed, with attention focused on the significance of the charged-assisted (CH)+···anion hydrogen bonds of simple azolium systems such as 1-butyl-3-methylimidazolium and 1-benzyl-3-methyl-1,2,3-triazolium salts

1,2-Diaryl(3-pyridyl)ethanone Oximes. Intermolecular Hydrogen Bonding Networks Revealed by X-ray Diffraction

The synthesis of a set of 1-aryl-2-aryl(3-pyridyl)ethanones 1-5 and thecorresponding ketoximes 6-9 is reported. Structural studies of oximes 6, 7 and 9 wereperformed in solution using 1H-NMR and in the solid state by X-ray crystallography,providing evidence of H-bonding networks. The crystal packing was controlled byhomomeric intermolecular oxime···oxime H-bond interactions for 6 and cooperativeoxime···N(pyridyl) and CH/π interactions for 7 and 9. Keywords: Oximes; ethanones; hydrogen bonds; self-assembly; X-ray diffraction crystalograph

Heterocyclic Betaines. XXIII. Access to Novel Dipolar Ethyleneimidazolium(pyridinium) 4-Nitrobenzimidazolate Inner Salts. Synthesis, Characterization and Reactivity Concerning a Type of .BETA.-Elimination Reaction

The first synthesis of some imidazolium(pyridinium) 4-nitrobenzimidazolate betaines with an ethylene interannular spacer has been performed. Their chemical behavior concerning a type of β-elimination reaction has also been studied and contrasted to that of their pyridinium counterparts

Synthetic approaches to multifunctional indenes

The synthesis of multifunctional indenes with at least two different functional groups has not yet been extensively explored. Among the plausible synthetic routes to 3,5-disubstituted indenes bearing two different functional groups, such as the [3-(aminoethyl)inden-5-yl)]amines, a reasonable pathway involves the (5-nitro-3-indenyl)acetamides as key intermediates. Although several multistep synthetic approaches can be applied to obtain these advanced intermediates, we describe herein their preparation by an aldol-type reaction between 5-nitroindan-1-ones and the lithium salt of N,N-disubstituted acetamides, followed immediately by dehydration with acid. This classical condensation process, which is neither simple nor trivial despite its apparent directness, permits an efficient entry to a variety of indene-based molecular modules, which could be adapted to a range of functionalized indanones

A simple halide-to-anion exchange method for heteroaromatic salts and ionic liquids

A broad and simple method permitted halide ions in quaternary heteroaromatic and ammonium salts to be exchanged for a variety of anions using an anion exchange resin (A− form) in non-aqueous media. The anion loading of the AER (OH− form) was examined using two different anion sources, acids or ammonium salts, and changing the polarity of the solvents. The AER (A− form) method in organic solvents was then applied to several quaternary heteroaromatic salts and ILs, and the anion exchange proceeded in excellent to quantitative yields, concomitantly removing halide impurities. Relying on the hydrophobicity of the targeted ion pair for the counteranion swap, organic solvents with variable polarity were used, such as CH3OH, CH3CN and the dipolar nonhydroxylic solvent mixture CH3CN:CH2Cl2 (3:7) and the anion exchange was equally successful with both lipophilic cations and anions

Azolium-based systems: application of an anion exchange resin (A- form) method and 1H NMR analysis of the charged-assisted (C<br>H)+·anion hydrogen bonds

The counteranion exchange of quaternary 1,2,3-triazolium salts was examined using a simple method that permitted halide ions to be swap for a variety of anions using an anion exchange resin (A¯ form). The method was applied to 1,2,3-triazolium-based ionic liquids and the iodideto- anion exchange proceeded in excellent to quantitative yields, concomitantly removing halide impurities. Additionally, an anion exchange resin (N3¯ form) was used to obtain the benzyl azide from benzyl halide under mild reaction. Likewise, following a similar protocol, bis(azidomethyl)arenes were also synthesized in excellent yields. The results of a proton NMR spectroscopic study of simple azolium-based ion pairs are discussed, with attention focused on the significance of the charged-assisted (CH)+···anion hydrogen bonds of simple azolium systems such as 1-butyl-3-methylimidazolium and 1-benzyl-3-methyl-1,2,3-triazolium salts

Heterocyclic betaines. XXII. Azinium(azolium) 4-nitrobenzimidazolate inner salts and their derivatives with several interannular spacers. Synthesis, characterization and antitrichomonal activity

The synthesis of an ensemble of pyridinium(imidazolium) 4-nitrobenzimidazolate bentaines and their derivatives with several interannular linkages has been explored. Their antiprotozoal activity has also been examined