2521-07-5Relevant academic research and scientific papers
Reversal of Regioselectivity in Catalytic Arene-Ynamide Cyclization: Direct Synthesis of Valuable Azepino[4,5-b]indoles and β-Carbolines and DFT Calculations
Li, Long,Chen, Xiu-Mei,Wang, Ze-Shu,Zhou, Bo,Liu, Xin,Lu, Xin,Ye, Long-Wu
, p. 4004 - 4010 (2017)
Ynamides are important building blocks in organic synthesis, and a variety of versatile synthetic methods have been developed in the past decade. Among these, catalytic cyclizations of π-tethered ynamides are particularly attractive, since this approach enables facile access to a diverse array of synthetically useful nitrogen heterocycles. However, due to the fact that the nitrogen atom is able to impose an electronic bias, these cyclizations exclusively occur on the α position of ynamides. Herein, we report the reversal of regioselectivity in arene-ynamide cyclization by copper catalysis, which represents the first catalytic π-tethered ynamide cyclization involving the reversal of regioselectivity. This strategy allows the expedient and practical synthesis of valuable azepino[4,5-b]indoles and β-carbolines in generally high yields under mild conditions. Moreover, the relevant mechanistic rationale for this cyclization, especially for the observed high regioselectivity, is strongly supported by density functional theory (DFT) calculations. The synthetic utility of this chemistry is also indicated by the synthesis of several biologically active compounds and natural product bauerine A.
Colorimetric and ratiometric fluorescence sensing of water based on 9-methyl pyrido[3,4-: b] indole-boron trifluoride complex
Enoki, Toshiaki,Ooyama, Yousuke
, p. 2086 - 2092 (2019/02/12)
In this work, 9-methyl pyrido[3,4-b]indole-boron trifluoride complex, 9-MP-BF3, was designed and developed as a colorimetric and ratiometric fluorescent sensor for the detection of water in the low- and high-water-content regions in solvents. In the low-water-content region, a new photoabsorption band at around 360 nm and a fluorescence band at around 370 nm gradually appeared due to the dissociation of 9-MP-BF3 into 9-methyl pyrido[3,4-b]indole (9-MP) by water molecules with a simultaneous decrease in the photoabsorption band at around 390 nm and the fluorescence band at around 460 nm originating from 9-MP-BF3. In the moderate-water-content region, the photoabsorption band at around 360 nm and the fluorescence band at around 370 nm gradually shifted to a longer wavelength region with an increase in the fluorescence intensity, which could be ascribed to the formation of a hydrogen-bonded complex (9-MP-H2O) with water molecules. Furthermore, in the high-water-content region, two photoabsorption bands at around 305 nm and 390 nm and one fluorescence band at around 460 nm gradually reappeared with simultaneous decrease in the photoabsorption band at around 290 nm and the fluorescence band at around 370 nm, which was attributed to the formation of a hydrogen-bonded proton transfer complex (9-MP-H+) with water molecules. Thus, this work revealed the mechanism of a colorimetric and ratiometric fluorescent sensor based on pyrido[3,4-b]indole-boron trifluoride complex for the detection of water over a wide range from low water content to high water content in solvents.
Photophysical and Photochemical Properties of Naturally Occurring normelinonine F and Melinonine F Alkaloids and Structurally Related N(2)- and/or N(9)-methyl-β-carboline Derivatives
Rasse-Suriani, Federico A. O.,García-Einschlag, Fernando S.,Rafti, Matías,Schmidt De León, Tobías,David Gara, Pedro M.,Erra-Balsells, Rosa,Cabrerizo, Franco M.
, p. 36 - 51 (2017/10/07)
In the present work, we have synthesized and fully characterized the photophysical and photochemical properties of a selected group of N-methyl-β-carboline derivatives (9-methyl-β-carbolines and iodine salts of 2-methyl- and 2,9-dimethyl-β-carbolinium) in aqueous solutions, in the pH range 4.0–14.5. Moreover, despite the quite extensive studies reported in the literature regarding the overall photophysical behavior of N-unsubstituted βCs, this work constitutes the first full and unambiguous characterization of anionic species of N-unsubstituted βCs (norharmane, harmane and harmine), present in aqueous solution under highly alkaline conditions (pH > 13.0). Acid dissociation constants (Ka), thermal stabilities, room temperature UV–visible absorption and fluorescence emission and excitation spectra, fluorescence quantum yields (ФF) and fluorescence lifetimes (τF), as well as quantum yields of singlet oxygen production (ФΔ) have been measured for all the studied compounds. Furthermore, for the first time to our knowledge, chemometric techniques (MCR-ALS and PARAFAC) were applied on these systems, providing relevant information about the equilibria and species involved. The impact of all the foregoing observations on the biological role, as well as the potential biotechnological applications of these compounds, is discussed.
Dehydrogenation of N-Heterocycles by Superoxide Ion Generated through Single-Electron Transfer
Huang, Yuan-Qiong,Song, Hong-Jian,Liu, Yu-Xiu,Wang, Qing-Min
supporting information, p. 2065 - 2069 (2018/01/27)
Nitrogen-containing heteroarene motifs are found in numerous pharmaceuticals, natural products, and synthetic materials. Although several elegant methods for synthesis of these compounds through dehydrogenation of the corresponding saturated heterocycles have been reported, some of the methods are hampered by long reaction times, harsh conditions, and the need for catalysts that are not readily available. This work reports a novel method for dehydrogenation of N-heterocycles. Specifically, O2.? generated in situ acts as the oxidant for N-heterocycle substrates that are susceptible to oxidation through a hydrogen atom transfer mechanism. This method provides a general, green route to N-heteroarenes.
Design, synthesis and in vitro cytotoxicity studies of novel β-carbolinium bromides
Venkataramana Reddy,Mishra, Shriprada,Tantak, Mukund P.,Nikhil, Kumar,Sadana, Rachna,Shah, Kavita,Kumar, Dalip
, p. 1379 - 1384 (2017/03/08)
A series of novel β-carbolinium bromides has been synthesized from easily accessible β-carbolines and 1-aryl-2-bromoethanones. The newly synthesized compounds were evaluated for their in vitro anticancer activity. Among the synthesized derivatives, compounds 16l, 16o and 16s exhibited potent anticancer activity with IC50values of 50= 3.16–7.93 μM). In order to test the mechanism of cell death, we exposed castration resistant prostate cancer cell line (C4-2) to compounds 16l and 16s, which resulted in increased levels of cleaved PARP1 and AO/EB staining, indicating that β-carbolinium salts induce apoptosis in these cells. Additionally, the most potent β-carbolines 16l and 16s were found to inhibit tubulin polymerization.
Synthesis and structure-activity relationships of N2-alkylated quaternary β-carbolines as novel antitumor agents
Zhang, Guoxian,Cao, Rihui,Guo, Liang,Ma, Qin,Fan, Wenxi,Chen, Xuemei,Li, Jianru,Shao, Guang,Qiu, Liqin,Ren, Zhenghua
, p. 21 - 31 (2013/10/01)
A series of novel N2-alkylated quaternary β-carbolines was synthesized by modification of position-1, 2, 7 and 9 of β-carboline nucleus with various alkyl and arylated alkyl substituents, and their cytotoxic activities in vitro and antitumor potencies in mice were evaluated. Compound 3m was found to be the most potent antitumor agent. SARs analysis revealed that (1) the substituents in position-2 and 9 of β-carboline nucleus played a vital role in modulation of antitumor activity; (2) the benzyl and 3-phenylpropyl substituents in position-2 and 9 of β-carboline ring were the optimal substituents giving rise to significant antitumor agent. These compounds might be a novel promising class of antitumor agents with clinical development potential.
HARMINE DERIVATIVES, INTERMEDIATES USED IN THEIR PREPARATION, PREPARATION PROCESSES AND USE THEREOF
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Page/Page column 47; 96, (2008/06/13)
This invention relates to compounds of general formula (I), wherein R1, R2, R3, R4 and R5 are as defined specification; intermediates used in their preparation, preparation processes and use thereof. The present invention produce harmine derivatives with enhanced antihumour activity and lower nervous system toxicity by structurally modification parent structure of β-carboline of harmines at position 1, 2, 3, 7 and 9, The compounds of the present invention can be pre easily with high yield. They can be used in manufacture of a variety of antitumour medicines and medicines used in treatm tumour diseases in combination of light or radiation therapy.
Synthesis, acute toxicities, and antitumor effects of novel 9-substituted β-carboline derivatives
Cao, Rihui,Chen, Qi,Hou, Xuerui,Chen, Hongsheng,Guan, Huaji,Ma, Yan,Peng, Wenlie,Xu, Anlong
, p. 4613 - 4623 (2007/10/03)
A series of novel 9-substituted β-carboline derivatives was synthesized from the starting material harmine and l-tryptophan, respectively. Cytotoxic activities, acute toxicities, and antitumor effects of these compounds were investigated. A series of nove
Efficient one-pot synthesis of anti HIV and antitumor compounds: Harman and substituted harmans
Kusurkar, Radhika S.,Goswami, Shailesh K.,Vyas, Sandhya M.
, p. 4761 - 4763 (2007/10/03)
Anti HIV and antitumor compounds, harman and substituted harmans have been synthesized using electrocyclization reactions as key steps. A one-pot reaction sequence was used to furnish these compounds in good overall yield.
Synthesis of β- and γ-carbolines by the palladium/copper-catalyzed coupling and cyclization of terminal acetylenes
Zhang, Haiming,Larock, Richard C.
, p. 7048 - 7056 (2007/10/03)
A variety of 3-substituted β- and γ-carbolines have been synthesized from N-substituted 3-iodoindole-2-carboxaldehydes and 2-bromoindole-3-carboxaldehydes, respectively. The coupling of these aldehydes with various terminal acetylenes with PdCl2(PPh3)2/CuI as the catalyst readily affords the corresponding alkynylindole carboxaldehydes, which have subsequently been converted to the corresponding tert-butylimines and cyclized to β- and γ-carbolines by either copper-catalyzed or thermal processes.
