123871-18-1Relevant articles and documents
Thermally Induced Denitrogenative Annulation for the Synthesis of Dihydroquinolinimines and Chroman-4-imines
Chou, Chih-Hung,Chen, Ying-Yu,Rajagopal, Basker,Tu, Hsiu-Chung,Chen, Kuan-Lin,Wang, Sheng-Fu,Liang, Chien-Fu,Tyan, Yu-Chang,Lin, Po-Chiao
, p. 757 - 765 (2016)
A rapid growth in synthetic methods for the preparation of diverse organic molecules using N-sulfonyl-1,2,3-triazoles is of great interest in organic synthesis. Transition metals are generally used to activate the α-imino diazo intermediates. Metal-free methods have not been studied in detail, but can be a good complement to transition metal catalysis in the mild reaction conditions. We herein report a novel method for the preparation of 2,3-dihydroquinolin-4-imine and chroman-4-imine analogs from their corresponding N-sulfonyl-1,2,3-triazoles in the absence of metal catalysts. To achieve intramolecular annulation, the introduction of an electron-donating group is required at the meta position of N-sulfonyl-1,2,3-triazole methyl anilines. The inclusion of tailored substituents on the aniline moieties and nitrogen atoms enhances the nucleophilicity of the phenyl π-electrons, thus allowing them to undergo a Friedel-Crafts-type reaction with the highly electrophilic ketenimines. This metal-free method was carefully optimized to generate a variety of dihydroquinolin-4-imines and chroman-4-imines in moderate-to-good yields.
Synthesis and Photophysical Characterization of 2,3-Dihydroquinolin-4-imines: New Fluorophores with Color-Tailored Emission
Chou, Chih-Hung,Rajagopal, Basker,Liang, Chien-Fu,Chen, Kuan-Lin,Jin, Dun-Yuan,Chen, Hsing-Yin,Tu, Hsiu-Chung,Shen, Yu-Ying,Lin, Po-Chiao
, p. 1112 - 1120 (2017/12/26)
In this study, a series of variously substituted 2,3-dihydroquinolin-4-imines (DQIs) were synthesized from N-substituted propargylanilines by copper(I)-catalyzed annulation. The approach adopted in this study under mild, effective conditions exhibited broad substrate tolerance, particularly for functional groups substituted on anilines. Most of the DQI derivatives synthesized under optimal conditions were obtained in good isolated yields of 63–88 %. 2,3-Dihydroquinolinimine thus obtained was easily converted to important structures like 2,3-dihydroquinolone and tetrahydrobenzodiazepin-5-one, confirming the importance of this strategy in constructing various heterocycles. Surprisingly, 2,3-dihydroquinolinimines thus obtained exhibited bright fluorescence with quantum yields up to 66 %. The density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations were performed for understanding the excited-state nature of DQI system. Accordingly, a tailored DQI derivative bearing methoxy group at C-6 position and acetoxy group at C-7 position was designed and synthesized to give emission at 559 nm with redshift compared to the 7-methoxy substituted DQI. A detailed study of DQI structures with their photophysical properties was performed with five control molecules and consequently demonstrated the uniqueness of the chemical structures of DQIs.
Non-oxidative Methodology for the Synthesis of Vinblastine and Vincristine Models
Magnus, Philip,Ladlow, Mark,Elliott, Jason,Kim, Chung Sook
, p. 518 - 520 (2007/10/02)
Fragmentation of the tetracyclic amine (5), initiated by a chloroformate to give the putative iminium ion (6) in the presence of an aromatic nucleophile, provides convenient access to model bis-alkaloids such as (7)-(15).
