Decarbonylation of N-carbazolylacetyl chloride in the friedel-crafts acylation reaction

Chemistry of Heterocyclic Compounds - Reaction products of N-carbazolylacetyl chloride under Friedel-Crafts reaction conditions include carbon monoxide, the reaction product from carbazole and...     

咔唑双乙酰化衍生物的合成及其电子光谱

以咔唑为原料,通过SN1亲核取代和Friedel-Crafts亲电取代反应合成了咔唑双乙酰化衍生物——3,6-二乙酰基-N-乙基咔唑和3,6-二乙酰基-N-丁基咔唑,其结构经1H NMR,IR,MS和元素分析表征,并讨论了它们的电子吸收光谱。     

Polycarbazoles via C?N coupling reactions of phthaloyl bis‐9H‐carbazoles with activated difluorides

1,3‐Phthaloyl bis‐9H‐carbazole (MPC) and 1,4‐phthaloyl bis‐9H‐carbazole (PPC) were synthesized by a Friedel‐Crafts reaction of carbazole with terephthaloyl chloride or isophthaloyl chloride. Homopolymers were obtained by a C? N coupling reaction with activated difluorides and copolymers were synthesized with 4,4′‐biphenol as a comonomer by a nucleophilic substitution reaction between these NH‐ and OH‐containing monomers and the activated difluoro monomers. The inherent viscosities of the polymers ranged from 0.35 to 1.03 dL/g. These polymers exhibited glass‐transition temperatures greater than 238 °C with the PPC‐containing homopolymer showing the highest value, 326.4 °C. The thermal stabilities indicated no significant weight loss below 450 °C and the temperatures of 5% weight loss ranged from 514.0 to 546.3 °C. The polymers showed reasonable solubility in organic solvents such as DMAC, DMSO, and NMP. UV absorption and fluorescence emission properties are presented. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4326–4331, 2009     

Microwave‐Assisted Synthesis of Antimicrobial Agents Containing Carbazole and Thiazole Moieties

An efficient synthesis of new derivatives of carbazole incorporated with thiazole moiety via the reaction of carbazole thiosemicarbazone with hydrazonoyl chloride under microwave irradiation. The spectral results and the electronic absorption data proved the postulated structures of the resulting compounds. The starting thiosemicarbazone and all the new derivatives were evaluated against two fungi, four G⁺ bacteria and G⁻ bacteria. The results obtained explore the high potency of some of the tested compounds compared with the employed standard bactericides and fungicides.     

Synthesis and characterization of a trefoil-shaped liquid crystal based on 1,3,5-triazine with carbazole groups

A trefoil-shaped liquid crystal containing an aromatic hetero-nucleus has been synthesized by the reaction of cyanuric chloride with 3,6-didecanoyl carbazole (DDC). The molecular structure was characterized by ¹H NMR and ¹³C NMR spectroscopy, mass spectroscopy and elemental analysis. The core consists of 1,3,5-triazine directly linked to three carbazole groups. The trefoil-shaped conformation is suggested by molecular modelling. The mesophase was investigated using DSC, X-ray diffraction and polarizing optical microscopy. The X-ray diffraction pattern of a sample cooled slowly from the isotropic state showed sharp peaks in the small angle and wide angle regions implying the existence of a columnar phase with interand intra-columnar ordering. An unusual reticular texture similar to a cholesteric texture was observed.     

Synthesis and characterization of a trefoil-shaped liquid crystal based on 1,3,5-triazine with carbazole groups

A trefoil-shaped liquid crystal containing an aromatic hetero-nucleus has been synthesized by the reaction of cyanuric chloride with 3,6-didecanoyl carbazole (DDC). The molecular structure was characterized by ¹H NMR and ¹³C NMR spectroscopy, mass spectroscopy and elemental analysis. The core consists of 1,3,5-triazine directly linked to three carbazole groups. The trefoil-shaped conformation is suggested by molecular modelling. The mesophase was investigated using DSC, X-ray diffraction and polarizing optical microscopy. The X-ray diffraction pattern of a sample cooled slowly from the isotropic state showed sharp peaks in the small angle and wide angle regions implying the existence of a columnar phase with interand intra-columnar ordering. An unusual reticular texture similar to a cholesteric texture was observed.     

Synthesis and fluorescence behavior of 3‐methacryamide‐9‐carbazole and its polymer 1

A novel acrylic monomer‐bearing carbazole chromophore, 3‐methacrylamide‐9‐ethyl‐carbazole and its model compound 3‐isobutyramide‐9‐ethylcarbazole were synthesized by reaction of 3‐amino‐9‐ethyl carbazole and the corresponding acyl chloride in the presence of triethylamine. It can be polymerized easily by using azo‐bisisobutyronitrile as an initiator or photopolymerized without any sensitizer. The photochemical behavior of 3‐methacrylamide‐9‐ethyl‐carbazole, its polymer and 3‐isobutyramide‐9‐ethylcarbazole were investigated by recording the fluorescence spectra in N,N‐dimethylformamide. It was found that the fluorescence intensity of the monomer is dramatically lower than those of its polymer and the model compound in the same chromophore concentration. This phenomenon, termed as the ‘structural self‐quenching effect’, was commonly observed for acrylic monomers bearing chromophore moieties and ascribed to the coexistence of the electron‐donating chromophore and the electron‐accepting double bond within one molecule. The strong fluorescence of the polymer can be quenched by adding electron‐deficient monomers having no chromophore moieties such as methyl methacrylate and acrylonitrile, and the Stern–Volmer constants were determined. It is observed that the higher the electron deficiencies of the quenchers, the higher the Stern–Volmer constants, implying a stronger quenching effect.Copyright © 2000 John Wiley & Sons, Ltd.     

Synthesis and biological evaluation of structural variants of carbazoquinocin C

Some new structural variants of the alkaloid carbazoquinocin C were synthesized in a few steps with good to excellent yields. The key step comprises a cyclisation reaction of appropriate 2‐vinylindoles with oxalyl chloride. The carbazole‐3,4‐quinones are able to trap oxygen‐centred radicals. In some biological/biochemical assays some of these compounds exhibit extraordinary results including inhibition of cyclooxygenase‐1 and 5‐lipoxygenase in the μM‐range. Moreover some of the carbazoquinocin C‐variants inhibit significant oxidative damage of cellular DNA in nM‐range.     

A Modified Synthesis of 9-(1,2-Dichlorovinyl)carbazole by Using Crown Ethers and Cryptands in a Non-aqueous System

The 9-[(E)-1,2-dichloroviny1]carbazole is a starting material for synthesis of 9-ethynyl-carbazole [1], which in term is monomer for preparation of photoconductive polymers [2]. Dichlorovinylation of carbazole in a solid-liquid two phase system in the presence of crown and cryptand catalysts has been studied. Application of the Phase Transfer Catalysis in the nonaqueous system increases yield of 9-[(E)-1,2-dichloroviny1]carbazole in comparison to the methods based on liquid-liquid system with benzyltriethylammonium chloride (TEBA) or dimethylsulfoxide (DMSO) as catalysts.     

Quantitative investigation of matrices for diffuse reflectance infrared Fourier transform spectrometry

Five materials were investigated for use as diluent matrices for diffuse reflectance infrared Fourier transform (DRIFT) spectrometry of powdered samples. DRIFT spectra of powdered carbazole dispersed in germanium, silicon, diamond, potassium chloride and a chalcogenide glass were compared. Three particle size ranges were investigated for five concentrations of carbazole ranging from 0.1-10%. The effects of particle size and refractive index of the matrix are discussed.     

Multi C−H Functionalization Reactions of Carbazole Heterocycles via Gold-Catalyzed Carbene Transfer Reactions

Herein we describe a multiple C−H functionalization reaction of carbazole heterocycles with diazoalkanes. We show that gold catalysts play a distinct role in enabling a multiple C−H functionalization reaction to introduce up to six carbene fragments onto molecules containing multiple carbazole units or to link multiple carbazole units into a single molecule. A one-pot stepwise approach enables the introduction of two different carbene fragments to allow orthogonal deprotection and straightforward derivatization.     

New Synthesis Method of N-Alkylation of Carbazole Under Microwave Irradiation in Dry Media.

Under microwave irradiation carbazole reacts remarkably fast with a number of alkyl halides to give N-alkyl derivatives of carbazole. The reaction were carried out with high yield by simply mixing carbazole with an alkyl halide which was adsorb on potassium carbonate.     

Polymerization of 3,6-Dibromo-9-(2,3-Epoxypropyl)Carbazole with Lewis Acids

Abstract

The kinetics of polymerization of 3,6-dibromo-9-(2,3-epoxypro-pyl) carbazole with stannic chloride and boron trifluoride etherate were studied by a microcalorimetric technique. Complex kinetics of the polymerization rate were observed. A spontaneous increase of the reaction rate was recorded after it decreased and after polymerization for some time at the minimal rate. This effect is explained by a change in the mechanism of polymerization. At the high enough degree of conversion, transition from an active chain end mechanism to an activated monomer mechanism takes place.     

Changes in the reactivity of the fluorescent reagents carbazole-9-carbonyl chloride and 9-carbazolylacetic acid in the presence of cyclodextrins

Carbazole-9-carbonyl chloride (C9CC) and 9-carbazolylacetic acid (9CAA) were selected as model fluorescent reagents. The effect of different chemically modified cyclodextrins (CDs) added to the aqueous solutions of these reagents was studied in water and in buffered aqueous solutions at pH 4.5 and 8.8. The CDs employed were 2-hydroxypropyl-β-cyclodextrin (HP-βCD), 2,3-di-O-methyl-β-cyclodextrin (DM-βCD) and 2,3,6-tri-O-methyl-β-cyclodextrin (TM-βCD). The inclusion of these reagents inside the cavities of the CDs was verified and this process can affect the derivatization reaction because CDs can modify the reactivity of the guest molecules. The basic conditions necessary for the derivatization reaction between C9CC and amines lead to the formation of carbazole anion through hydrolysis followed by decarboxylation. In the presence of CDs, the hydrolysis-decarboxylation of carbazole-9-carbonyl chloride is faster than in buffered aqueous homogeneous solutions. The behaviour observed for these reagents in aqueous solutions of CDs was compared to the one observed in basic ethanolic solutions. These changes are particularly noticeable in the case of 2,3-di-O-methyl-β-CD and 2-hydroxypropyl-β-CD. The characteristics of the fluorescent reagents are compared to carbazole and 9-methylcarbazole as model compounds. This paper was presented at XIIIth International Cyclodextrin Symposium. Torino, Italy, May 14–17, 2006.     

Access to polycyclic carbazoles from ring-fused 2-(9H-carbazol-1-yl)anilines

Abstract

Nine 2-(9H-carbazol-1-yl)anilines with rings fused at the 3,4-position were acylated at the amino group with chloroacetyl, 3-chloropropanoyl, or 4-chlorobutyryl chloride, at yields of 85–99%. The resulting ω-chloroamides were exposed to potassium tert-butoxide in THF. All nine acetamides annulated exclusively at the carbazole N atom, giving benzodiazocinocarbazoles at 76–91% overall yield. The only propanamide prepared underwent α,β-elimination, giving the corresponding acrylamide at 70% overall yield. All nine butanamides annulated exclusively at the amide nitrogen, giving pyrrolidin-2-ones at 70–94% overall yield. Additionally, the 1-indanone derived carbazolylaniline followed the same annulation pattern, but the benzylic methylene group was oxidized, giving the corresponding fluorenones. The cyclohexanone-derived carbazolylaniline was also converted into a maleimide, which participated in a Diels-Alder reaction with cyclopentadiene. Attempts to replace the amino group in the starting material via diazotization were unsuccessful. Instead, a Widman-Stoermer reaction was observed, in which the diazonium group attacked the carbazole 2-position, giving the corresponding cinnoline.     

Generation of Electrophilic Iodine from Iodine Monochloride in Neutral Media. Iodination and Protodeiodination of Carbazole

In reaction of iodine monochloride with CF₃COOAg, CH₃COONa or (CH₃COO)₂Pb in acetonitrile and acetic acid the chloride is bonded by metal cations, and electrophilic iodine is generated able to easily iodinate anthracene and carbazole. However at the iodination of anthracene in the presence of oxygen the prevailing process is anthracene oxidation to anthraquinone. In the presence of sulfuric acid protodeiodination of 3-iodocarbazole was found to occur resulting in rearranged products.     

Amino acid promoted CuI-catalyzed C-N bond formation between aryl halides and amines or N-containing heterocycles

CuI-catalyzed coupling reaction of electron-deficient aryl iodides with aliphatic primary amines occurs at 40 degrees C under the promotion of N-methylglycine. Using l-proline as the promoter, coupling reaction of aryl iodides or aryl bromides with aliphatic primary amines, aliphatic cyclic secondary amines, or electron-rich primary arylamines proceeds at 60-90 degrees C; an intramolecular coupling reaction between aryl chloride and primary amine moieties gives indoline at 70 degrees C; coupling reaction of aryl iodides with indole, pyrrole, carbazole, imidazole, or pyrazole can be carried out at 75-90 degrees C; and coupling reaction of electron-deficient aryl bromides with imidazole or pyrazole occurs at 60-90 degrees C to provide the corresponding N-aryl products in good to excellent yields. In addition, N,N-dimethylglycine promotes the coupling reaction of electron-rich aryl bromides with imidazole or pyrazole to afford the corresponding N-aryl imidazoles or pyrazoles at 110 degrees C. The possible action of amino acids in these coupling reactions is discussed.     

Copper(II)-mediated oxidative coupling of 2-aminonaphthalene homologues. Competition between the straight dimerization and the formation of carbazoles

Whereas the Cu(II)-mediated oxidative coupling of 2-aminonaphthalenes 7a and 7b results in the clean formation of 1,1'-binaphthyls 13a and 13b, respectively, their higher homologues and congeners 8-12 have been found to exhibit a different reaction pattern. Thus, 2-aminoanthracene (8) gave a approximately 1:1 mixture of the expected bianthryl derivative 15 and the carbazole 16, whereas the 9-aminophenanthrene (10), 3-phenyl-1-aminonaphthalene (11), and 2-aminochrysene (12) produced almost exclusively the corresponding carbazoles 19, 20, and 21, respectively. By contrast, the isomeric 3-aminophenanthrene (9) gave rise to the azo compound 17 as a result of the preferential oxidation on the nitrogen. The carbazoles have been shown to arise directly from the coupling reactions rather than from the primarily formed binaphthyls. Alternatively, carbazole 19 can also be prepared from 1b on reaction with hydrazine. On the other hand, treatment of 3a with hydrazine resulted in the formation of a approximately 2:7 mixture of amine 11 and arylhydrazine 22. 2,2'-Diamino-1,1'-bianthryl (15) has been resolved into enantiomers via cocrystallization with (-)-N-benzylcinchonidinium chloride and shown to have (R)-(-)-15 configuration by X-ray crystallography.     

A novel total synthesis of the bioactive poly-substituted carbazole alkaloid carbazomadurin A

A new total synthesis of the neuronal cell-protecting carbazole alkaloid carbazomadurin A is described. The key step was an allene-mediated electrocyclic reaction involving an indole [b]-bond for the construction of a highly substituted carbazole ring. The E-alkenyl side chain at the C1 position of carbazole was introduced between O-triflate and alkenyl pinacol borate using the Suzuki-Miyaura reaction. SEM groups were cleaved with TBAF and the formyl group was reduced to provide carbazomadurin A.     

New chalcones containing carbazole and 3,4-ethylenedioxythiophene fragments

Russian Journal of Organic Chemistry - Acylation of 9-(2-ethylhexyl)carbazole with acetyl bromide in the presence of tin(IV) chloride gave 3-acetyl- and 3,6-diacetyl-9-(2-ethylhexyl)carbazoles...