72105-96-5Relevant academic research and scientific papers
Enhancement of the carbamate activation rate enabled syntheses of tetracyclic benzolactams: 8-oxoberbines and their 5- And 7-membered C-ring homologues
Kurouchi, Hiroaki
supporting information, p. 653 - 658 (2021/02/06)
A route to the direct amidation of aromatic-ring-tetheredN-carbamoyl tetrahydroisoquinoline substrates was developed. This route enabled general access to 8-oxoberberines and their 5- and 7- membered C-ring homologues. It overcomes the undesired tandem side-reactions that result in the destruction of the isoquinoline backbone, which inevitably occurred under our previously reported superacidic carbamate activation method.
A Method for Bischler-Napieralski-Type Synthesis of 3,4-Dihydroisoquinolines
Min, Lin,Yang, Weiguang,Weng, Yunxiang,Zheng, Weiping,Wang, Xinyan,Hu, Yuefei
supporting information, p. 2574 - 2577 (2019/04/30)
A new method for the Bischler-Napieralski-type synthesis of 3,4-dihydroisoquinolines was developed by a Tf2O-promoted tandem annulation from phenylethanols and nitriles. Its success was mainly due to the fact that a phenonium ion was formed in the process and practically functioned as a stable and reactive primary phenylethyl carbocation.
Method for solvent accelerated selective dehydrogenation of tetrahydroisoquinoline type compound
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Paragraph 0039; 0040; 0041; 0042; 0043, (2017/07/22)
The invention discloses a method for synthesizing 1-substituted-3,4-dihydroisoquinoline through the solvent accelerated selective partial dehydrogenation of a 1-substituted-1,2,3,4-tetrahydroisoquinoline compound. For a simple and easily obtained cyclic amine type compound such as a tetrahydroisoquinoline compound, a corresponding imine compound can be obtained through selective dehydrogenation; the conversion ratio of the cyclic amine type compound is higher; further, the proportion of a partially dehydrogenated product to a fully dehydrogenated product is more than 20 to 1. The method is simple and convenient to operate, is practical, easy and feasible, and is mild in reaction condition; the actual cost is greatly reduced. In addition, a method for synthesizing 3,4-dihydroisoquinoline through the direct dehydrogenation of tetrahydroisoquinoline has the advantages of atom economy and environmental friendliness.
Enantioselective, Copper-Catalyzed Alkynylation of Ketimines to Deliver Isoquinolines with α-Diaryl Tetrasubstituted Stereocenters
Dasgupta, Srimoyee,Liu, Jixin,Shoffler, Clarissa A.,Yap, Glenn P. A.,Watson, Mary P.
supporting information, p. 6006 - 6009 (2016/12/09)
An enantioselective, copper-catalyzed alkynylation of cyclic α,α-diaryl ketiminium ions has been developed to deliver isoquinoline products with diaryl, tetrasubstituted stereocenters. The success of this reaction relied on identification of Ph-PyBox as the optimal ligand, i-Pr2NEt as the base, and CHCl3 as the solvent. A broad scope and functional group tolerance were observed. Notably, the use of both aryl and silyl acetylenes results in high yields and enantioselectivities. Mechanistic experiments are consistent with a dimeric or higher order catalyst.
Solvent-promoted highly selective dehydrogenation of tetrahydroisoquinolines without catalyst and hydrogen acceptor
Feng, Guang-Shou,Ji, Yue,Liu, Hui-Fang,Shi, Lei,Zhou, Yong-Gui
supporting information, p. 747 - 749 (2016/02/05)
An unusual solvent DMF-promoted dehydrogenation of 1-substituted 1,2,3,4-tetrahydroisoquinolines to synthesize cyclic imines is described. This environmentally friendly reaction features no requirement of any metal catalysts, oxidants, or hydrogen acceptors. A wide range of structurally varied 3,4-dihydroisoquinolines can be obtained with good yields and excellent chemoselectivities.
Palladium carbon catalyzed selective partial dehydrogenation method of tetrahydroisoquinoline
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Paragraph 0044-0047; 0050, (2017/02/09)
The invention relates to a method for synthesis of 1-substituted-3, 4-dihydroisoquinoline by palladium carbon catalyzed selective partial dehydrogenation of a 1-substituted-1, 2, 3, 4-tetrahydroisoquinoline compound. The reaction temperature is 0-80DEG C. For easily available cyclic amine compounds like tetrahydroisoquinoline, a corresponding imine compound can be obtained through selective dehydrogenation, the conversion rate is up to 99%, and the proportion of a partial dehydrogenation product and a complete dehydrogenation product is greater than 20:1. The method provided by the invention has simple and practical operation, the raw materials and catalyst are cheap and easily available, the reaction conditions are mild, and the catalyst can be recycled, thus greatly reducing the actual cost. In addition, the method for synthesis of 3, 4-dihydroisoquinoline through direct dehydrogenation of tetrahydroisoquinoline has the advantages of atom economy and environmental friendliness.
Highly selective partial dehydrogenation of tetrahydroisoquinolines using modified Pd/C
Ji, Yue,Chen, Mu-Wang,Shi, Lei,Zhou, Yong-Gui
, p. 33 - 39 (2015/09/28)
A highly selective procedure has been developed for the partial dehydrogenation of 1-substituted-1,2,3,4-tetrahydroisoquinolines over K3PO4·3H2O-modified Pd/C catalyst. This new method provides facile, atom-economical and environmentally friendly access to 1-substituted-3,4-dihydroisoquinolines without the need for stoichiometric amounts of harmful oxidants. The use of standard Pd/C as a catalyst for this process gave poor chemoselectivity. Pleasingly, the use of a K3PO4·3H2O-modified Pd/C catalyst promoted the partial dehydrogenation of 1-substituted-1,2,3,4-tetrahydroisoquinolines with excellent chemoselectivity by suppressing further dehydroaromatization. Furthermore, conducting the reaction under an atmosphere of oxygen led to further improvements in the chemoselectivity of the dehydrogenation, with the ratio of imine to isoquinoline reaching up to 32/1. The heterogenous Pd/C catalyst could also be recycled and reused at least three times with excellent conversion and chemoselectivity, demonstrating the significantly practical potential of this methodology.
