112891-31-3Relevant articles and documents
Enhancement of the carbamate activation rate enabled syntheses of tetracyclic benzolactams: 8-oxoberbines and their 5- And 7-membered C-ring homologues
Kurouchi, Hiroaki
, 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.
Diprotonative stabilization of ring-opened carbocationic intermediates: conversion of tetrahydroisoquinoline to triarylmethanes
Kurouchi, Hiroaki
, p. 8313 - 8316 (2020/08/17)
Superacid-promoted conversion of tetrahydroisoquinolines to triarylmethanes via tandem reactions of C-N bond scission, Friedel-Crafts alkylation, C-O bond scission, and electrophilic aromatic amidation was developed. Dication formation was important for stabilizing the ring-opened carbocationic intermediate, which is a new role for diprotonation in reaction mechanisms. This journal is
Hybrid Catalysis Enabling Room-Temperature Hydrogen Gas Release from N-Heterocycles and Tetrahydronaphthalenes
Kato, Shota,Saga, Yutaka,Kojima, Masahiro,Fuse, Hiromu,Matsunaga, Shigeki,Fukatsu, Arisa,Kondo, Mio,Masaoka, Shigeyuki,Kanai, Motomu
supporting information, p. 2204 - 2207 (2017/02/23)
Hybrid catalyst systems to achieve acceptorless dehydrogenation of N-heterocycles and tetrahydronaphthalenes-model substrates for liquid organic hydrogen carriers-were developed. A binary hybrid catalysis comprising an acridinium photoredox catalyst and a Pd metal catalyst was effective for the dehydrogenation of N-heterocycles, whereas a ternary hybrid catalysis comprising an acridinium photoredox catalyst, a Pd metal catalyst, and a thiophosphoric imide organocatalyst achieved dehydrogenation of tetrahydronaphthalenes. These hybrid catalyst systems allowed for 2 molar equiv of H2 gas release from six-membered N-heterocycles and tetrahydronaphthalenes under mild conditions, i.e., visible light irradiation at rt. The combined use of two or three different catalyst types was essential for the catalytic activity.
Prototype Pictet-Spengler reactions catalyzed by superacids. Involvement of dicationic superelectrophiles
Yokoyama, Akihiro,Ohwada, Tomohiko,Shudo, Koichi
, p. 611 - 617 (2007/10/03)
The Pictet-Spengler reaction, an acid-catalyzed intramolecular cyclization of intermediate imines of 2-arylethylamine to give 1,2,3,4- tetrahydroisoquinolines, has long been limited to active substrates which bear strongly electron-donating groups such as a methoxy or a hydroxy group on the cyclizing benzene ring. In this paper, we present superacid-catalyzed Pictet-Spengler reactions of imines of 2-phenethylamine, including the prototype Pictet-Spengler reaction of N-methylene-2-phenethylamine, to give the parent and 1-substituted 1,2,3,4-tetrahydroisoquinolines in moderate to high yields. The yields are dependent on the acidity of the media. A linear relationship was found between the rate of the cyclization and the acidity of the reaction media in kinetic studies of N-methylene-2-phenethylamine and related imines, strongly supporting the intervention of an additional protonative activation of the N-protonated imines, that is, the involvement of dicationic superelectrophiles, N,N-diprotonated imines (ammonium- carbenium dications). We further found that the prototype cyclization of the parent N-methylene-2-phenethylamine is also catalyzed by TFA to give 1,2,3,4- tetrahydroisoquinoline in good yield, although the cyclization is significantly slower than that catalyzed by superacids. The prototype Pictet- Spengler cyclization of N-methylene-2-phenethylamine can thus take place both through the monocation (the N-monoprotonated imine) and the dication (the N,N-diprotonated imine), the latter reaction being predominant in superacids.
Free-Radical Chemistry of Imines
Tomaszewski, Miroslaw J.,Warkentin, John,Werstiuk, Nick H.
, p. 291 - 322 (2007/10/02)
Aryl radicals bearing an aldimino functional group as part of an ortho substituent cyclized by addition to C and/or N of the imino group.When the choice was between 5-exo closure to C and 6-endo closure to N, the former predominated.However, 6-endo closure to C predominated over 5-exo cyclization to N in isomeric imines.Absolute values of cyclization rate constants were determined and an explanation for the unusual 6-endo preference is offered.Chiral induction in 6-endo cyclization to C of an aldimine from D-glyceraldehyde acetonide was observed, and its sense was determined.
Phencyclidine-like Effects of Tetrahydroisoquinolines and Related Compounds
Gray, Nancy M.,Cheng, Brian K.,Mick, Stephen J.,Lair, Cecelia M.,Contreras, Patricia C.
, p. 1242 - 1248 (2007/10/02)
A series of 1,2,3,4-tetrahydroisoquinolines, tetrahydrothienopyridines, and related compounds were evaluated for their ability to inhibit binding of -1--N-allylnormetazocine to phencyclidine (PCP) and ? receptors, respectively.A representative series of compounds was evaluated in behavioral assays to determine the ability of the compounds to induce PCP-like stereotyped behavior and ataxia.All of the compounds caused stereotyped behavior and ataxia, indicating their agonist actions at the PCP site.
