Carbazoles, alkylation

Keywords carbazole, alkyl halide, /V-alkylation, microwave irradiation, /V-alkyl-carbazole... 

In a related reaction, a number of aryloic compounds, behaving as ketonic moieties in the Fischer indolisation, have been shown to afford carbazoles in the Japp-Maitland condensation. For example, when either I-naphthol, 2-naphthol, 6-alkyl-2-naphthol, ... 

Oddo reported that the organomagnesium derivatives of p3Trole, indole, skatole, and carbazole could be prepared in a single operation by mixing the parent heterocyclic compound with an alkyl halide and magnesium in anhydrous ether.The product formed was reported to be the same as that obtained by the more conventional procedure. However, this approach to the synthesis of the indole Grignard reagents does not seem to have been exploited in subsequent work. 

The indol-3-yl-substituted indolo[2,3-()]carbazole 143 has been isolated as a product from the complex mixture generated by the decomposition of urorosein (144) (99CHE561). Interestingly, when subjected to alkylation conditions involving sodium hydride and dimethyl sulfate in THF, 143 was transformed into the N. -dimethyl derivative 145 in 36% yield (00MI2). 

In an effort toward indolo[3,2-h]carbazoles based on Lewis acid-assisted dimerization of benzotriazole derivatives, the necessary starting materials 197 were prepared in good yields from 1-propargylbenzotriazole and 2-iodoaniline followed by alkylation. In the ensuing dimerization step, compounds 197 were treated with zinc chloride in refluxing dichlorometane to afford the indolo[3,2-h]carbazoles 199 or the dihydro derivatives 198 (Scheme 27). Under similar conditions 197, where R = = H, did not undergo dimerization, which suggests that the alkyl... 

Alkylation of the dimethylpiperazine 12 with 3-chloropropanol followed by treatment of the product 13 with thionyl chloride gives the halide 14. Alkylation of the anion from carbazole (15) with that halide leads to the tricyclic antipsychotic agent rimcazole (16) [4]. 

The DszC enzyme was able to convert the following compounds other than DBT thioxanthen-9-one, 2,8-dimethyl DBT, 4,6-dimethyl DBT, and 3,4-benzo DBT. Non-organosulfur compounds such as biphenyl, carbazole, and dibenzofuran did not show any activity. This indicates that dszC specifically recognizes sulfur atom [151]. One study specifically examined the DszC enzyme for oxidation of aryl sulfides [179] and reported oxidation of many sulfides including, naphthyl methyl sulfide, phenyl methyl sulfide, and its alkyl derivatives. 

Carbazole is a non-basic nitrogen compound, whose removal via hydrotreating is limited by its low reactivity. The removal of nitrogen by hydrotreatment involves a number of steps that take place on the catalyst surface. The weak interaction of neutral nitrogen compounds with catalysts precludes carbazole and its derivatives from being denitro-genated and makes them the most recalcitrant components in HDN of gas oils [308], In fact, it has been found that the nitrogen content of hydrotreated gas oil from Athabasca bitumen was composed primarily of alkyl carbazoles [309],... 

Several species of the genus Pseudomonas have been isolated that degrade carbazole and its alkyl derivatives and a variety of other microorganisms have been reported to mineralize non-basic nitrogen compounds, including species of Bacillus, Xanthomonas, Burkholderia, Comamonas, Beijerinckia, Mycobacterium, and Serratia [310],... 

A two phase process, in which the feedstock (e.g., petroleum) was mixed with water and an organic solvent to improve denitrogenation of aromatic nitrogen compounds [102], led to an improvement of the process. Additionally, a surfactant was used to increase the interfacial area. Carbazole and quinoline and their alkyl derivatives were used as primary compounds for demonstration. The biocatalyst is used in resting stage and is continuously fed to the system to keep the reaction rate at an acceptable level. It was observed that quinoline was hardly removed under the conditions at which carbazole was decomposed and assimilated. 

Tricarbonyl(cyclohexadienyl)iron cations react with a variety of nucleophiles to give substituted tricarbonyl(cyclohexadienyl)iron complexes88 with arylamines, N- or C-alkylation can occur depending on the nature of aryl ring substituents. Deligation of C-alkylated arylamines can be achieved by either ferric chloride, which gives the free arylamine, or by iodine in the latter case, cyclization with concomitant oxidation occurs, and carbazoles are produced in moderate yield (Scheme 52).89... 

Under microwave irradiation several azaheterocycles (i.e. pyrrole, imidazole, indole and carbazole) can react remarkably fast with alkyl halides to give, exclusively, N-al-kyl derivatives (Eqs. 32 and 33) [45, 46]. Such reactions have been performed simply by mixing an azaheterocycle compound with 50% excess alkyl halide and a catalytic amount of TBAB. The reactants were absorbed either on a mixture of potassium carbonate and potassium hydroxide or on potassium carbonate alone and then irradiated in a domestic microwave oven for 30 s-10 min. 

Carbazol-9-yl)-l,3,4-thiadiazole-2(3/7)-thione 159 was S-alkylated with monochloroacetic acid to give the 1,3,4-thiadiazole 160 (Equation 59) <2006PS1737>. 

Fuostifoline (47), a furo[3,2-a]carbazole, was isolated from Murraya euchrestifolia. Timdri s total synthesis of 47 commenced with alkylation of bromocresol 43 with bromoacetaldehyde diethyl acetal and P4Oio-promoted cyclization to furnish 5-bromo-7-methylbenzofuran (44) [47]. The Suzuki coupling of boronic acid 45, derived from 44, with o-bromonitrobenzene yielded biaryl 46. Nitrene generation, achieved via deoxygenation of nitro compound 46 using triethyl phosphite, was followed by cyclization to fuostifoline (47). 

A. Iraqi and I. Wataru, Preparation and properties of 2,7-linked A-alkyl-9JL-carbazole main-chain polymers, Chem. Mater., 16 442M48, 2004. 

Flexible and semiflexible chains for the connection of carbazole units have been used by Braun et al. [43, 44]. However, it can clearly be seen that introducing longer alkyl spacers lowers the Tg. In addition to carbazoles, the... 

Alkylation of pyrroles, indoles and carbazoles under liquidiliquid two-phase conditions with an added organic solvent... 

Carbazole [7,24] has been alkylated under phase-transfer conditions analogous to those used for indoles and pyrroles. 

Nitrogen alkylation occurs easily under sonochemical conditions [128], Indole and carbazole undergo N-alkylation with increased rates and yields under sonication in the presence of polyethylene glycol methyl ether as PTC. No reaction occurs in the absence of the PTC (Eq. 3.28). 

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