A General Method for Acylation of Indoles at the 3-Position with Acyl Chlorides in the Presence of Dialkylaluminum Chloride

Okauchi, Tatsuo; Itonaga, Masaaki; Minami, Tōru; Owa, Takashi; Kitoh, Kyosuke; Yoshino, Hiroshi

doi:10.1021/ol005841p

Cited by 158 publications

(85 citation statements)

References 7 publications

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“…Indole was alkylated with either 1-bromobutane or 1-bromopentane to quantitatively afford the desired N-alkylindoles 10 and 11, respectively. Subjecting N-alkylindoles 10 and 11 to acylation under Okauchi conditions [43] with freshly prepared 2-methoxybenzoyl chloride, 3-methoxybenzoyl chloride, or 4-methoxybenzoyl chloride gave the desired products in excellent yields after chromatographic purification.…”

Section: Resultsmentioning

confidence: 99%

Structure–activity relationships of synthetic cannabinoid designer drug RCS-4 and its regioisomers and C4 homologues

et al. 2015

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-1-yl-(1-pentyl-1H-indol-3-yl)methanone] represents the first of several Nalkyl-3-(methoxybenzoyl)indoles identified by forensic scientists as synthetic cannabinoid (SC) designer drugs. Despite the detection of RCS-4 and several analogues (RCS-2, RCS-3, RCS-2-C4, RCS-3-C4, and RCS-4-C4) in products intended for human consumption, relatively little is known about this class of cannabinoids. The synthesis of all regioisomers of RCS-4 and their C4 homologues is described. This study also systematically explored the structure-activity relationships of this class of SCs at human CB 1 and CB 2 receptors using an in vitro fluorometric imaging plate reader membrane potential assay. All compounds demonstrated agonist activity at CB 1 (EC 50 = 54-574 nM) and CB 2 (EC 50 = 4.5-46 nM) receptors, with the C4 homologues showing a preference for CB 2 receptors over CB 1 receptors (31-42 times). Since most of the analogues (RCS-2, RCS-3, RCS-2-C4, RCS-3-C4 and RCS-4-C4) are not subject to regulation in much of the world, despite their activities towards CB 1 and CB 2 receptors, there is a possibility that these analogues will emerge on the black market.

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Section: Resultsmentioning

confidence: 99%

Structure–activity relationships of synthetic cannabinoid designer drug RCS-4 and its regioisomers and C4 homologues

et al. 2015

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“…Based on the characteristics of MIL-53(Al) with Lewis acid (Al 3+ ) catalytic active centers of uniform distribution, a study of the Friedel-Crafts acylation reaction between indole and benzoyl chloride was initiated. Table 5 shows a comparison of catalytic performance for the Friedel-Crafts acylation reactions of indole with benzoyl chloride using the traditional Lewis acid catalysts AlCl 3 [6], Et 2 AlCl [35], ZrCl 4 [31], and the MIL-53(Al) produced in this work.…”

Section: Reaction Mechanismmentioning

confidence: 99%

Metal-organic framework MIL-53(Al): synthesis, catalytic performance for the Friedel-Crafts acylation, and reaction mechanism

Yan

Jiang

et al. 2015

Sci. China Chem.

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Metal-organic framework MIL-53(Al) was synthesized by a solvothermal method using aluminum nitrate as the aluminium source and 1,4-benzenedicarboxylic acid (H 2 BDC) as the organic ligand. The structure of samples was characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The catalytic activity and recyclability of MIL-53(Al) catalyst for the Friedel-Crafts acylation reaction of indole with benzoyl chloride were evaluated. The reaction conditions were optimized and a reaction mechanism was suggested. The results showed that the MIL-53(Al) catalyst exhibited good catalytic activity and recyclability for the Friedel-Crafts acylation reaction. When the molar ratio of indole and MIL-53(Al) catalyst was 1:0.06 (n 1 :n catalyst ), the molar ratio of indole and benzoyl chloride was 1:3, and the solvent was dichloromethane, the conversion of indole could reach 97.1% and the selectivity of 3-acylindole could reach 81.1% at 25 °C after 8 h. The catalyst can be reused without significant degradation in catalytic activity. After the catalyst was reused five times, the conversion of indole was 87.6% and the selectivity of 3-acylindole was 79.5%.

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“…7,10 In this procedure the substrate indole is stirred in dichloromethane with 1.5 equiv of dimethylaluminum chloride at 0°C for up to 1 h. To this intermediate organoaluminum compound is added 1.5 equiv of the acyl halide. 11 Evidence for the formation of an organoaluminum intermediate follows from the observation that reaction of 1-pentylindole with dimethylaluminum chloride and quenching with D 2 O provided 3-deuterio-1-pentylindole.…”

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confidence: 99%

1-Pentyl-3-phenylacetylindoles, a new class of cannabimimetic indoles

Huffman

Szklennik

Almond

et al. 2005

Bioorganic & Medicinal Chemistry Letters

114

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A General Method for Acylation of Indoles at the 3-Position with Acyl Chlorides in the Presence of Dialkylaluminum Chloride

Cited by 158 publications

References 7 publications

Structure–activity relationships of synthetic cannabinoid designer drug RCS-4 and its regioisomers and C4 homologues

Structure–activity relationships of synthetic cannabinoid designer drug RCS-4 and its regioisomers and C4 homologues

Metal-organic framework MIL-53(Al): synthesis, catalytic performance for the Friedel-Crafts acylation, and reaction mechanism

1-Pentyl-3-phenylacetylindoles, a new class of cannabimimetic indoles

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