Triphenylphosphonium Bromide Research Articles

Preparation, Crystal Structures, and Spectroscopic and Chemical Properties of 2,4,6-Trifluorophenyl- or 4-(Methoxycarbonyl)phenyl-Substituted (E)-1-(3-Guaiazulenyl)ethylene and (2E,4E)-1-(3-Guaiazulenyl)-1,3-butadiene Derivatives

Abstract Wittig reactions in general provide a mixture of E and Z geometric isomers, while reactions of 2,4,6-trifluorobenzaldehyde [and (E)-3-(2,4,6-trifluorophenyl)propanal] with the Wittig reagent (3-guaiazulenyl)triphenylphosphonium bromide in ethanol containing NaOEt at 25 °C for 24 h under argon give only new E (and 2E,4E)-forms selectively, i.e., (E)-1-(3-guaiazulenyl)-2-(2,4,6-trifluorophenyl)ethylene and (2E,4E)-1-(3-guaiazulenyl)-4-(2,4,6-trifluorophenyl)-1,3-butadiene. For comparative purposes, Wittig reactions of methyl 4-formylbenzoate, 4-(dimethylamino)benzaldehyde, methyl 4-[(E)-2-formylethenyl]benzoate, and (E)-3-[4-(dimethylamino)phenyl]propanal: namely, possessing an electron-withdrawing (–COOCH3) {or an electron-donating [–N(CH3)2]} group at the C-4 position of the benzene ring, with (3-guaiazulenyl)triphenylphosphonium bromide in methanol (or ethanol) containing NaOMe (or NaOEt) at 25 °C for 24 h under argon afford a mixture of the corresponding geometric isomers respectively. Along with spectroscopic properties and crystal structures of the isolated products, the chemical behavior of those products toward 1,1,2,2-tetracyanoethylene (TCNE) in benzene at 25 °C for 24 h under argon is reported with a view to comparative study.

Preparation and Anticorrosion Property of Polyaniliane/Organo-Clay Nanocomposite Coatings: Comparative Studies of Different Intercalating Agent

In this study, we present the first systematically comparative studies for the effect of intercalating agent on the property of polyaniline (PANI) -clay nanocomposite (PCN) materials. First of all, (4-carboxybutyl) triphenyl-phosphonium bromide (PC-4) and dodecyltriphenyl-phosphonium bromide (PC-12) were used as intercalation agent, separately, for the preparation of organophilic clay through cationic exchange reactions with Na+-montmorillonite (Na+-MMT) clay. Subsequently, organophilic clay was blending with aniline monomers followed by performing in-situ conventionally oxidative polymerization to give series of PCN materials. Subsequently, the as-prepared materials were characterized by Fourier-Transformation infrared (FTIR) spectroscopy, wide-angle powder X-ray diffraction (WXRD), and transmission electron microscopy (TEM). It should be noted that Na+-MMT modified with PC12 was found to reveal better dispersion than that of PC4-modified clay existed in polymer matrix based on studies of WAXRD and TEM. It should be noted that the PCN coatings containing PC12-modified clay platelets was found to reveal better corrosion protection than that of containing PC4-modified clay based on series of electrochemical corrosion measurements in saline. Effect composition on the electrical conductivity, optical and molecular weight of PANI of as-prepared PCN materials was also investigated by four-point probe technique, UV-visible absorption spectroscopy and gel permeation chromatography (GPC), respectively.

Kinetics of the reaction of propylene oxide with carbon dioxide in the presence of tetrasubstituted ammonium and phosphonium halogenides

Reactions of alkylene oxides with carbon dioxide underlie the industrial technology of ethylene- and propylene carbonates. Looking for new catalytic systems for these processes remains of interest due to the possibility of creating a new energy-saving process for the production of ethylene and propylene glycols. This work is aimed at comparing the catalytic activity of halogenides in the reaction of propylene oxide (PO) and carbon dioxide in the presence of tetrasubstituted ammonium and phosphonium halogenides, and evaluating the feasibility of using them in designing industrial technologies for the production of alkylene carbonates and glycols as active catalytic systems. Triphenylphosphine halogenides have been shown to possess high catalytic activity as compared to triethanolamine-based analogs. In terms of efficiency, triphenylphosphonium bromides are as good as the familiar catalysts based on potassium iodide. The high activity of these catalysts in the reaction for propylene carbonate (PC) production and their good solubility in the reaction medium allow us to propose them for the development of industrial technology for the subsequent production of alkyl carbonates and alkylene glycols.

Synthesis of ethyl (±)-(13,15-dideoxy)-16-methyl-9-oxoprosta-13(E,Z),15(E)-dienoate

The condensation of ethyl 7-(2-oxo-5-formulcyclopentyl)heptanoate by Wittig reaction with the ylide prepared from [(2E)-3-methylhept-2-en-1-yl]triphenylphosphonium bromide afforded ethyl (±)-(13,15-dideoxy)-16-methyl-9-oxoprosta-13(E,Z),15(E)-dienoate as a mixture of two isomers, 2:1.

Mechanical properties and rheological behavior of poly(butylene terephthalate)/clay nanocomposites with different organoclays

Poly(butylene terephthalate)–clay nanocomposites with three different organically modified clays were prepared via melt blending in a twin-screw extruder. Decyl triphenylphosphonium bromide, hexadecyl triphenylphosphonium bromide, and cetyl pyridinium chloride were used to modify the naturally occurring montmorillonite clay. The organically modified clays were characterized with X-ray diffraction for the d001-spacing and with thermogravimetric analysis to determine the thermal stability. The prepared nanocomposites were injection-molded and examined for the dispersion quality of the clay, the mechanical properties, and the rheological behavior. The tensile strength of the nanocomposites increased with a 1% addition of clay; however, more clay decreased the tensile strength. Nanocomposites with finely dispersed clay platelets and nanocomposites with poorly dispersed clay platelets showed very different rheological behaviors. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

ChemInform Abstract: A New Stereocontrolled Synthesis of Dihydroxerulin, a Potent Noncytotoxic Inhibitor of the Biosynthesis of Cholesterol.

Abstract Dihydroxerulin, 1 , has been stereoselectively synthesized by a convergent approach in which a key step was the Wittig reaction between ( Z )-5-[( E )-3-formyl-2-propenylidene]-5 H -furan-2-one, 15 , and the phosphonium ylid which derived from [( E )-2-decen-4,6-diyn-1-yl]triphenylphosphonium bromide, 19 . Compound 19 was conveniently prepared by a short reaction sequence involving a Stille reaction between 1-trimethylstannyl-1,3-heptadiyne, 17 , and ( E )-3-iodo-2-propen-1-ol, 18 . On the other hand, compound 15 was prepared in eight steps by a reaction sequence in which an immediate precursor to this butenolide, i.e. ( Z )-5-[(2 E )-4-hydroxy-2-butenylidene]-5 H -furan-2-one, 34 , was regio- and stereoselectively synthesized by Ag(I)-catalysed lactonization of the corresponding ( Z )-2-en-4-ynoic acid. The structure and stereochemistry of 1 were established on the basis of its 1 H and 13 C NMR spectra at 600 and 150 MHz, respectively, and by a combination of 2D NMR techniques.

ChemInform Abstract: Observations on the Use of Triphenylphosphonium Bromide as a Mild and Quantifiable Source of Hydrogen Bromide for Chemoselective Ring Opening of Epoxides to Bromohydrins.

The chemoselective ring opening of epoxides to bromohydrins in the presence of ketal, benzyloxymethoxy and trimethylsilyl ether functionality using triphenylphosphonium bromide is described. The preparation of a polymer supported variant is also reported.

ChemInform Abstract: New Nonsteroidal Steroid 5α-Reductase Inhibitors. Syntheses and Structure-Activity Studies on Carboxamide Phenylalkyl-Substituted Pyridones and Piperidones.

In the search for nonsteroidal inhibitors of 5 alpha-reductase for the treatment of benign prostatic hyperplasia (BPH), we synthesized diisopropyl (1a-8a) and tert-butyl (1b-8b) benzamides, as well as ethyl benzoates (1c, 3c), which were substituted in 4 position via variable alkyl spacer (n = 0: 1-4, n = 1: 5, 7 and n = 3: 6, 8) with a 1-methyl-2-pyridone (1, 2, 5, 6) or a 1-methyl-2-piperidone (3, 4, 7, 8) moiety mimicking steroidal ring A. The directly connected benzamides (1a-4a, 1b-4b) and benzoates (1c, 3c) were obtained by palladium-catalysed coupling reaction of diethyl(3-pyridyl)-borane with 4-bromobenzoic acid derivatives, followed by alpha-oxidation of the 1-methyl-pyridinium salt and subsequent separation of the regioisomers. Catalytic hydrogenation of the pyridones (1, 2) led to the piperidones (3, 4). The preparation of the benzamides with a methylene (5, 7) and a propylene spacer (6, 8), respectively, started with the reduction of the keto group of 5-benzoyl-1,2-dihydro-1-methyl-2(1H)-pyridone and catalytic hydrogenation of the alkene obtained by Wittig reaction of 5-formyl-1,2-dihydro-1-methyl-2(1H)-pyridone with (2-phenylethyl)triphenylphosphonium bromide, respectively. The phenyl ring was functionalized by Friedel-Crafts reaction, haloform cleavage to give the acid, formation of the acid chloride, and subsequent treatment with the appropriate amines. Again, catalytic hydrogenation of the pyridones (5, 6) led to the piperidones (7, 8). The 5 alpha-reductase inhibitory properties were determined using rat ventral prostate, as well as human BPH tissue as enzyme source, 1 beta-2 beta-[3H]testosterone as substrate and a HPLC procedure for the separation of dihydrotestosterone (DHT). Tested at a concentration of 100 microM, the inhibition values of 1-8 ranged from 0-79%. Significant differences were observed between rat and human enzyme. The most active compound was ethyl 4-(1-methyl-2-oxopiperid-5-yl)benzoate 3c (68%) for the human enzyme and N,N-bis(1-methylethyl)-4-[3-(1,2-dihydro-1-methyl-2-oxopyrid-5-yl) propyl] benzamide 6a (79%) for the rat enzyme.

Highly sensitive and positively charged precolumn derivatization reagent for amines and amino acids in liquid chromatography/electrospray ionization tandem mass spectrometry

We have developed a highly sensitive and positively charged precolumn derivatization reagent, (5-N-succinimidoxy-5-oxopentyl)triphenylphosphonium bromide (SPTPP), for amines and amino acids in liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS). The handling of the derivatization reaction is quite simple and the reagent reacts with the analytes rapidly and with high efficiency. The derivatized analytes were observed to form regular and intense product ions upon MS/MS analysis; thus, highly sensitive and selective detection was possible in the selected reaction monitoring (SRM) mode. The limits of detection of the SPTPP-derivatized analytes were less than sub-femtomole levels. The sensitivities of the derivatized analytes increased about 500-fold compared to those of underivatized analytes. Since the hydrophobicities of the samples increased after their derivatization, the resolution of the analytes improved dramatically when a reversed-phase system was used. The relative standard deviations of intra-day and inter-day variations were below 10.6% and 13.3%, respectively. The accuracy ranged between 86.6-113% and 83.4-113%, respectively. Furthermore, the developed reagent was used for the analysis of the neurotransmitter 4-aminobutanoic acid (GABA) and oxidative stress markers such as oxidized, nitrated, and halogenated tyrosines in rat serum.

Ternary mixtures of alkyltriphenylphosphonium bromides (C12TPB, C14TPB and C16TPB) in aqueous medium: their interfacial, bulk and fluorescence quenching behaviour

The self-aggregation behaviour of ternary mixtures of alkyl (C12-, C14- and C16-) triphenylphosphonium bromides was studied by conductometry and tensiometry. The pure surfactants showed two Critical Micellar Concentrations (CMCs) by conductometry, but their ternary mixtures produce single CMC both by conductometry and tensiometry. The CMC values determined were found to be lower than that obtained from Clint equation suggesting synergistic interaction among the monomers within the micelles. Their bulk properties, like fraction of counterions bound to the micelles and free energy of micellization were evaluated. Interfacial parameters, like surface excess, minimum head group area of monomer and free energy of adsorption were also assessed. Interfacial adsorption was found to be more spontaneous than micellization. The head group area per monomer in ternary systems was larger than pure systems due to stronger electrostatic repulsion among the charged head groups. The values of the packing parameters supported the pure as well as ternary micelles to be spherical. The TPB surfactants efficiently quenched pyrene fluorescence; the performances of the homologues in this respect were assessed.

Preparation, crystal structure, and spectroscopic, chemical, and electrochemical properties of (2 E,4 E)-4-[4-(dimethylamino)phenyl]-1-(3-guaiazulenyl)-1,3-butadiene compared with those of ( E)-2-[4-(dimethylamino)phenyl]-1-(3-guaiazulenyl)ethylene

Wittig reaction of 3-[4-(dimethylamino)phenyl]propanal ( 5) with (3-guaiazulenylmethyl)triphenylphosphonium bromide ( 4) in ethanol containing NaOEt at 25 °C for 24 h under argon gives the title (2 E,4 E)-1,3-butadiene derivative 6E in 19% isolated yield. Spectroscopic properties, crystal structure, and electrochemical behavior of the obtained new extended π-electron system 6E, compared with those of the previously reported ( E)-2-[4-(dimethylamino)phenyl]-1-(3-guaiazulenyl)ethylene ( 12), are documented. Furthermore, reaction of 6E with 1,1,2,2-tetracyanoethylene (TCNE) in benzene at 25 °C for 24 h under argon affords a new Diels–Alder adduct 8 in 59% isolated yield. Along with spectroscopic properties of the [π4+π2] cycloaddition product 8, the crystal structure, possessing a cis-3,6-substituted 1,1,2,2-tetracyano-4-cyclohexene unit, is shown. Moreover, reaction of 6E with ( E)-1,2-dicyanoethylene (DCNE) under the same reaction conditions as the above gives no product; however, this reaction in p-xylene at reflux temperature (138 °C) for four days under argon affords a new Diels–Alder adduct 9 in 54% isolated yield. Although reaction of 6E with DCNE in toluene at reflux temperature (110 °C) for four days under argon provides 9 very slightly, reaction of 6E with dimethyl acetylenedicarboxylate (DMAD) in toluene at reflux temperature for two days under argon yields a new Diels–Alder adduct 10, in 58% isolated yield, which upon oxidation with MnO 2 in CH 2Cl 2 at 25 °C for 1 h gives 11, converting a (CH 3) 2N-4″ into CH 3NH-4″ group, in 37% isolated yield. The crystal structure of 11 supports the molecular structure 10 possessing a partial structure cis-3,6-substituted 1,2-dimethoxycarbonyl-1,4-cyclohexadiene. The title basic studies on the above are reported in detail.

Preparation and Structures of New Azobenzene Derivatives with a 3-Guaiazulenylvinyl Group

Abstract Wittig reactions of (E)-4-(4-methoxyphenyldiazenyl)benzaldehyde and (E)-4-[4-(dimethylamino)phenyldiazenyl]benzaldehyde with (3-guaiazulenylmethyl)triphenylphosphonium bromide in ethanol in the presence of sodium ethoxide at 25 °C for 24 h under argon give only E forms (E)-4-{(E)-4-[2-(3-guaiazulenyl)vinyl]phenyldiazenyl}methoxybenzene and (E)-N,N-dimethyl-4-{(E)-4-[2-(3-guaiazulenyl)vinyl]phenyldiazenyl}aniline in 71 and 73% yields. Comparative studies on spectroscopic properties and crystal structures of the two new extended π-electron systems with those of structurally related (and delocalized) π-electron systems (3-guaiazulenyl)[(E)-4-(4-methoxyphenyldiazenyl)phenyl]methylium ion and {(E)-4-[4-(dimethylamino)phenyldiazenyl]phenyl}(3-guaiazulenyl)methylium ion compounds are reported. Similarly, Wittig reaction of (E)-diphenyldiazene-4,4′-dicarbaldehyde with the same reagent under the same reaction conditions as the above affords only E forms (E)-4-{(E)-4-[2-(3-guaiazulenyl)vinyl]phenyldiazenyl}benzaldehyde and (E)-bis{(E)-4-[2-(3-guaiazulenyl)vinyl]phenyl}diazene in 7 and 24% yields. Furthermore, reaction of guaiazulene (=7-isopropyl-1,4-dimethylazulene) with (E)-diphenyldiazene-4,4′-dicarbaldehyde in methanol in the presence of hexafluorophosphoric acid at 25 °C for 30 min provides (E)-diphenyldiazene-4,4′-bis(3-guaiazulenylmethylium) bis(hexafluorophosphate) in 46% yield which upon reduction with NaBH4 in a mixed solvent of ethanol and acetonitrile at 25 °C for 30 min gives (E)-bis[4-(3-guaiazulenylmethyl)phenyl]diazene in 88% yield. Comparative studies of spectroscopic properties of a new extended π-electron system (E)-bis{(E)-4-[2-(3-guaiazulenyl)vinyl]phenyl}diazene with those of a new delocalized π-electron system (E)-diphenyldiazene-4,4′-bis(3-guaiazulenylmethylium) bis(hexafluorophosphate) are documented.

A 99mTc-Labeled Triphenylphosphonium Derivative for the Early Detection of Breast Tumors

A greater mitochondrial membrane potential in tumor cells has been shown to enhance the accumulation of triphenyl phosphonium derivatives. The aim of this study was to synthesize and characterize (99m)Tc-labeled alkyl triphenyl phosphonium ((99m)Tc-Mito(10)-MAG3) for the early detection of breast tumors. Mito(10)-MAG3 was synthesized by coupling (10-aminodecyl)triphenyl phosphonium bromide with NHS-MAG3 and radiolabeled with (99m)Tc. Biodistribution and pharmacokinetics of (99m)Tc-Mito(10)-MAG3 was investigated in female Sprague-Dawley rats. Initially, (99m)Tc-Mito(10)-MAG3 was tested in animals with established breast tumors. In a subsequent longitudinal study, the imaging efficacy of (99m)Tc(10)-Mito-MAG3 for detecting small, nonpalpable breast tumors was assessed after chemically inducting breast carcinoma. Tumors detected by imaging were allowed to grow to palpable size and confirmed by histology. The results were compared with (99m)Tc-MIBI. The synthesis of Mito(10)-MAG3 was confirmed by mass spectrometry. The compound was radiolabeled with (99m)Tc to > 92% in a single step. The radiopharmaceutical exhibited fast blood clearance and low cardiac uptake. In the initial study, using animals with established breast tumors, (99m)Tc-Mito(10)-MAG3 imaging detected small lesions that were missed by palpation. In the longitudinal study, (99m)Tc-Mito(10)-MAG3 exhibited focal uptake in small breast tumors, which were confirmed by histology. Imaging, using (99m)Tc-Mito(10)-MAG3, allowed the early detection of small neoplastic lesions in the mammary glands. The agent significantly reduced cardiac uptake, compared with (99m)Tc-MBIB. The phosphonium-based derivatives warrant further characterization and development as imaging agents for scintimammography.

Process Development and Scale Up of a Glycine Antagonist

A synthetic route amenable to large-scale synthesis of the glycine antagonist (2R,4E)-7-chloro-4-(2-oxo-1-phenyl-pyyrrolidin-3-ylidene)-1,2,3,4-tetrahydroquinoline-2-carboxylic acid, (2R,3R,4R,5S)-6-(methylamino)hexane-1,2,3,4,5-penta-ol 12 is presented. The route consists of four stages of chemistry. Stage 1 starts from 5-chloro-2-iodoaniline hydrochloride and is a three-step telescoped stage consisting of an imine formation with ethyl glyoxalate, Mannich reaction using vinyloxytrimethylsilane, and subsequent Wittig reaction with (2-oxo-1-phenyl-3-pyrrolidinyl)triphenylphosphonium bromide. The stage 1 product (4E)-2[(5-chloro-2-iodophenyl)amino]-4-(2-oxo-1-phenyl-pyrrolidin-3-ylidene)butanoic acid ethyl ester 17 is subjected to an enzyme-catalysed kinetic resolution to prepare the single (2R)-enantiomer 19 as the ethyl ester. Stage 3 is the intramolecular Heck reaction to yield (2R,4E)-7-chloro-4-(2-oxo-1-phenyl-pyrrolidin-3-ylidene)-1,2,3,4-tetrahydroquinoline-2-carboxylic acid ethyl ester 31. The final stage is ester saponification and meglumine salt formation to afford the drug candidate molecule 12. In total, more than 300 kg of target 12 was produced with a purity >99.9%. Aspects of route selection as well as elements of process understanding and control are discussed.

Synthesis of a mitochondria-targeted spin trap using a novel Parham-type cyclization

A new cyclic nitrone spin trap, [4-(3′,3′-dibutyl-2′-oxy-3′H-isoindol-5′-yloxy)butyl]triphenylphosphonium bromide (MitoSpin), bearing a lipophilic cation has been prepared by a route that involves a novel Parham-type lithiation–cyclization of an isocyanate to give the isoindolinone core. MitoSpin accumulates in a membrane potential dependent way in energized mitochondria and its oxidation could potentially be used in the study of oxidative stress resulting from reactive oxygen species generated in mitochondria.

A Flexible Synthesis of 2,3-Disubstituted Indoles from Aminobenzyl Phosphonium Salts. A Direct Synthesis of Rutaecarpine

The reaction of substituted (2-aminobenzyl)triphenylphosphonium bromides with aromatic aldehydes or alpha,beta-unsaturated aldehydes constitutes a new synthesis of 2,3-disubstitued indoles in high yields. The adduct from 4-oxo-3,4-dihydroquinazoline-2-carbaldehyde was an advanced intermediate in the synthesis of several rutaecarpines.

Design and synthesis of novel pinacolylboronate containing combretastatin ‘antimitotic agent’ analogues

We developed a procedure to synthesize pinacolyl boronate containing stilbene derivatives and used this procedure to synthesize boron-containing combretastatin analogues. The key step involves the Wittig reaction of the ylide 4-(4,4,5,5-tetramethyl-1,3,2-dioxaboratophenyl)-methyl triphenylphosphonium bromide 11 with 3,4,5-trimethoxy benzaldehyde in the presence of t BuONa in DMF, providing 88% yield. We are now in a position to evaluate the biological activity of these derivatives as modulators of TGF-beta signaling pathways.

Comparison Between Structures and Properties of ABS Nanocomposites Derived from Two Different Kinds of OMT

In the present work, the hexadecyl triphenyl phosphonium bromide (P16) and cetyl pyridium chloride (CPC) were used to modify montmorillonite (MMT) based on the structural characteristic of the engineering thermoplastic acrylonitrile-butadiene-styrene copolymer (ABS) and the principle of “like dissolves like”, and then used to prepare the ABS/organic-modified montmorillonite (OMT) nanocomposites by melt-intercalation method. The influences of two different kinds of OMT on the structures and properties of the ABS nanocomposites were characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution electron microscopy (HREM), thermogravimetric analyses (TGA), Cone calorimetry and dynamic mechanical analyses (DMA), respectively. The increased basal spacing showed that ABS intercalated into the gallery of the OMT. The morphology indicated that the OMT dispersed well in the ABS resin and the intercalated structure for ABS/OMT-P16 nanocomposites and intercalated-exfoliated structure for ABS/OMT-CPC nanocomposites were respectively formed. The TGA results revealed that onset temperature of thermal degradation and charred residue at 700 °C of the ABS nanocomposites was remarkably enhanced compared to the pure ABS. It was also found from the Cone calorimetry tests that the peak of heat release rate (PHRR) decreased significantly, contributing to the reduced flammability. The DMA measurements indicated that the loading of silicate clays improved the storage modulus of the ABS resin. The partial exfoliation of the OMT-CPC within ABS nanocomposites was advantageous to increasing thermal stability properties, decreasing flammability properties, and improving mechanical properties.

Reaction of 2,4-dinitrophenylhydrazones of triphenyl(2-aroylethyl)phosphonium bromides with aqueous alkali and some transformations of the betaines formed

Triphenyl(2-p-toluoylethyl)- and triphenyl(2-p-bromobenzoylethyl)phosphonium bromide 2,4-dinitrophenylhydrazones were established to form a bipolar compounds with a negatively charged nitrogen atom and a positively charged phosphonium atom, under the action of aqueous alkali at 0°C. When refluxed in acetonitrile, the product formed from triphenyl(2-p-toluoylethyl)phosphonium bromide undergoes cleavage by a five-membered ring mechanism to give triphenylphosphine and tolyl vinyl ketone 2,4-dinitrophenylhydrazone. The reactions of the above betains with methyl iodide give rise to N-alkylation and cleavage products, but, in addition, iodide analogs of the starting phosphonium salt 2,4-dinitrophenylhydrazones which are probably formed via N→C negative charge transfer, C-methylation, and reaction of the resulting products with N-betaines.

Preparation, Crystal Structures, and Properties of New Conjugated π-Electron Systems with 3-Guaiazulenyl and 4-(Dimethylamino)phenyl Groups

Abstract Reaction of guaiazulene with 1,2-bis[4-(dimethylamino)phenyl]-1,2-ethanediol in methanol in the presence of hydrochloric acid at 60 °C for 3 h gives 1,1-bis[4-(dimethylamino)phenyl]-2-(3-guaiazulenyl)ethylene, in 81% yield, via pinacol rearrangement and further Wittig reaction of 3-formylguaiazulene with [4-(dimethylamino)benzyl]triphenylphosphonium bromide in ethanol containing NaOEt at 25 °C for 24 h under argon affords (E)-2-[4-(dimethylamino)phenyl]-1-(3-guaiazulenyl)ethylene in 12% yield. Crystal structures as well as spectroscopic and electrochemical properties of the products, with a view to comparative study, are reported. Moreover, reactions of the products with 2 equiv of tetracyanoethylene (TCNE) in benzene at 25 °C for 24 h under argon give 1,1,2,2,11,11,12,12-octacyano-3,3-bis[4-(dimethylamino)phenyl]-8-isopropyl-5,10-dimethyl-1,2,3,6,9,10a-hexahydro-6,9-ethanobenz[a]azulene and 1,1,2,2,11,11,12,12-octacyano-3-[4-(dimethylamino)phenyl]-8-isopropyl-5,10-dimethyl-1,2,3,6,9,10a-hexahydro-6,9-ethanobenz[a]azulene in 74 and 41% yields. A plausible reaction pathway for the formation of the unique products, possessing interesting structures, is submitted.