179556-14-0Relevant academic research and scientific papers
Synthesis method for preparing 2-substituted indole derivative
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Paragraph 0087-0090, (2019/05/28)
The invention relates to a synthesis method for preparing a 2-substituted indole derivative. The method includes the following steps: mixing aromatic amine compounds (I), ketone compounds (II) and a drying agent in an organic solvent; adding a palladium catalyst; and reacting in an aerobic weak acid environment to prepare the indole compounds (III). (I), (II) and (III) are as shown in the specification, wherein R1 is selected from hydrogen, C1-C6 alkyl, C1-C6 alkoxy, C1-C6 alkanoyl, C2-C6 alkenyl, C2-C6 alkynyl, halogen, hydroxyl, substituted or unsubstituted amino, substituted or unsubstituted phenyl, pyridyl and heterocyclic aryl; (I) can be pyridylamine, pyrimidylamine, pyridazinam or pyrazinamide which may further be substituted or unsubstituted; and the substituents are selected fromone or more C1-C6 alkyl, C1-C6 alkoxy, C1-C6 alkanoyl, C2-C6 alkenyl, C2-C6 alkynyl, halogen, hydroxyl, amino; and R2 is selected from C1-C6 alkyl, formate groups or C1-C6 alkylamide groups.
Carboxylic Acid-Promoted Single-Step Indole Construction from Simple Anilines and Ketones via Aerobic Cross-Dehydrogenative Coupling
Ren, Long,Nan, Guanglei,Wang, Yongcheng,Xiao, Zhiyan
, p. 14472 - 14488 (2018/11/23)
The cross-dehydrogenative coupling (CDC) reaction is an efficient strategy for indole synthesis. However, most CDC methods require special substrates, and the presence of inherent groups limits the versatility for further transformation. A carboxylic acid-promoted aerobic catalytic system is developed herein for a single-step synthesis of indoles from simple anilines and ketones. This versatile system is featured by the broad substrate scope and the use of ambient oxygen as an oxidant and is convenient and economical for both laboratory and industry applications. The existence of the labile hydrogen at C-3 and the highly transformable carbonyl at C-2 makes the indoles versatile building blocks for organic synthesis in different contexts. Computational studies based on the density functional theory (DFT) suggest that the rate-determining step is carboxylic acid-assisted condensation of the substrates, rather than the functionalization of aryl C-H. Accordingly, a pathway via imine intermediates is deemed to be the preferred mechanism. In contrast to the general deduction, the in situ formed imine, instead of its enamine isomer, is believed to be involved in the first ligand exchange and later carbopalladation of the α-Me, which shed new light on this indolization mechanism.
