ChemInform Abstract: Lithium Perchlorate Catalyzed Reactions of Indoles: An Expeditious Synthesis of Bis(indolyl)methanes (original) (raw)
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Indoles and their derivatives are used as antibiotics in the field of pharmaceuticals Bis(indolyl)alkanes and their derivatives constitute an important group of bioactive metabolites. Cellulose Supported Perchloric Acid (CSPA) was found to be a mild, efficient and reusable solid acid catalyst in electrophilic substitution reaction of indoles with various aldehydes and ketones to afford the corresponding bis(indolyl)methane. The significant features of this method are excellent yields of the products under solvent-free conditions and non-toxicity of the catalyst.
ChemInform, 2012
A rapid and highly efficient synthesis of various bis(indolyl)methanes with high yield by the reaction of indoles 1a-c and arylaldehydes 2a'-m' in presence of fuller's earth is demonstrated. This simple and versatile protocol is found to be an efficient catalyst for the electrophilic addition reaction of indole and works well under solvent free condition as well as in aqueous medium. The structure of newly synthesized compound 3m has been confirmed by single crystal X-ray crystallography.
A new catalytic method for the preparation of bis-indolyl and tris-indolyl methanes in aqueous media
Catalysis Communications, 2007
Some new metal dodecyl sulfates were prepared by the reaction of sodium dodecyl sulfate and the corresponding metal nitrates. All of the prepared salts catalyzed the condensation of indoles with aldehydes and ketones. Among of them, zirconium tetrakis(dodecyl sulfate), Zr(DS) 4 , was superior to others. Bis-and tris-indolyl methanes were synthesized at room temperature in high yields by using Zr(DS) 4 under aqueous media. Zr(DS) 4 was also recovered and reused for new runs.
New 3H-Indole Synthesis by Fischer’s Method. Part I.
Methyl indolenines (4a-c) and (5a-c) were prepared in high yield by a Fischer indole synthesis reaction of o,m-tolylhydrazine hydrochlorides (1a-b) with isopropyl methyl ketone (2) and 2-methylcyclohexanone (3) in acetic acid at room temperature. o,p-Nitrophenylhydrazines (1c-d) were reacted with 2-methylcyclohexanone (3) in acetic acid at reflux to give nitroindolenines (5d-e), while the attempted reactions of o,pnitrohydrazines with isopropyl methyl ketone (2) in acetic acid were not successful. Compounds (1c-d) were reacted with isopropyl methyl ketone (2) in acetic acid/HCl to give 2,3,3-trimethyl-5-nitro-indolenine (4e) and 2,3,3-trimethyl-7-nitroindolenine (4d).
Novel Indole Chemistry in the Synthesis of Heterocycles
Current Organic Chemistry, 2005
Indoles that are substituted at the 2-or 3-position with electron-withdrawing groups (nitro, phenylsulfonyl) undergo nucleophilic addition, 1,3-dipolar cycloaddition, and Diels-Alder reactions to give a variety of indoles, pyrroloindoles, and carbazoles. New methods for the synthesis of furo [3,4-b]indoles and the novel ring system furo[3,4-b]pyrrole are described for the first time. Diels-Alder reactions of furo [3,4-b]pyrroles afford indoles after dehydration of the primary cycloadducts. Efficient syntheses of both 2-and 3-nitroindoles from indole are reported, and the first generation and successful electrophilic trapping of a 2,3-dilithioindole has been achieved.
Synthesis of Medicinally Important Indole Derivatives: A Review
The Open Medicinal Chemistry Journal, 2021
Indoles constitute a widely occurring functional group in nature and are present in an extensive number of bioactive natural products and medicinally important compounds. As a result, exponential increases in the development of novel methods for the formation of indole core along with site-specific indoles have been established. Conventional methods for the synthesis of indoles are getting replaced with green methods involving ionic liquids, water as a solvent, solid acid catalyst, microwave irradiation and the use of nanoparticles under solvent-free conditions. In addition, there are immense applications of the substituted indoles in diverse fields.