- Anionic Rearrangement of BF3-complexed N-Allyl and Aryl Tetrahydroisoquinolines.
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BF3-complexed N-Allyl and N-benzyl tetrahydroisoquinolines react, at -20 deg C to 0 deg C in THF, with sec-BuLi to give 1-substituted tetrahydroisoquinolines.
- Kessar, S. V.,Singh, Paramjit,Singh, Kamal Nain,Kaul, Vijay K.,Kumar, Gurdeep
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- Enhancement of the carbamate activation rate enabled syntheses of tetracyclic benzolactams: 8-oxoberbines and their 5- And 7-membered C-ring homologues
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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.
- Kurouchi, Hiroaki
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supporting information
p. 653 - 658
(2021/02/06)
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- Photocatalytic deaminative benzylation and alkylation of tetrahydroisoquinolines with N-alkylpyrydinium salts
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A ruthenium-catalyzed photoredox coupling of substituted N-aryltetrahydroisoquinolines (THIQs) and different bench-stable pyridinium salts was successfully developed to give fast access to 1-benzyl-THIQs. Furthermore, secondary alkyl and allyl groups were also successfully introduced via the same method. Additionally, the typically applied N-phenyl group in the THIQ substrate could be replaced by the cleavable p-methoxyphenyl (PMP) group and successful N-deprotection was demonstrated.
- No?l, Timothy,Sambiagio, Carlo,Sch?nbauer, David,Schnürch, Michael
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p. 809 - 817
(2020/05/18)
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- Alkaloid constituents from flower buds and leaves of sacred lotus (Nelumbo nucifera, Nymphaeaceae) with melanogenesis inhibitory activity in B16 melanoma cells
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Methanolic extracts from the flower buds and leaves of sacred lotus (Nelumbo nucifera, Nymphaeaceae) were found to show inhibitory effects on melanogenesis in theophylline-stimulated murine B16 melanoma 4A5 cells. From the methanolic extracts, a new alkaloid, N-methylasimilobine N-oxide, was isolated together with eleven benzylisoquinoline alkaloids. The absolute stereostructure of the new alkaloid was determined from chemical and physicochemical evidence. Among the constituents isolated, nuciferine, N-methylasimilobine, (-)-lirinidine, and 2-hydroxy-1-methoxy-6a,7-dehydroaporphine showed potent inhibition of melanogenesis. Comparison of the inhibitory activities of synthetic related alkaloids facilitated characterization of the structure-activity relationships of aporphine- and benzylisoquinoline-type alkaloids. In addition, 3-30 μM nuciferine and N-methylasimilobine inhibited the expression of tyrosinase mRNA, 3-30 μM N-methylasimilobine inhibited the expression of TRP-1 mRNA, and 10-30 μM nuciferine inhibited the expression of TRP-2 mRNA.
- Nakamura, Seikou,Nakashima, Souichi,Tanabe, Genzo,Oda, Yoshimi,Yokota, Nami,Fujimoto, Katsuyoshi,Matsumoto, Takahiro,Sakuma, Rika,Ohta, Tomoe,Ogawa, Keiko,Nishida, Shino,Miki, Hisako,Matsuda, Hisashi,Muraoka, Osamu,Yoshikawa, Masayuki
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p. 779 - 787
(2013/02/25)
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- 4,5-Dihydrothiazoline - A new protecting and activating group for generation of α-aminocarbanions of secondary amines
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4,5-Dihydrothiazoline has been successfully used as a protecting and activating group for synthesis of various 1-substituted 1,2,3,4- tetrahydroisoquinolines via a lithiation-electrophillic substitution reaction sequence. Copyright Taylor & Francis Group, LLC.
- Singh, Kamal Nain,Singh, Paramjit,Kaur, Amarjit
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p. 3339 - 3343
(2007/10/03)
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- Steps towards a practical synthesis of macrocyclic bisbenzylisoquinolines
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There are more than 400-reported bisbenzylisoquinoline alkaloids, many with interesting biological activity, but the reported syntheses are long and low yielding. As a result, there have been no systematic attempts at exploitation of the potential therapeutic applications. The concept of a sulfur 'stitch', restricting the conformational freedom of intermediates in the synthesis, will potentially allow analogues of the natural products to be prepared using relatively efficient routes. The synthesis of intermediate sulfur heterocycles is reported, based on 2,8-dimethylphenoxathiin, leading via 2,8-bis(bromomethyl) phenoxathiin-10,10-dioxide to a synthesis of 3,4,8,9-tetrahydro-13-oxa-6-thia-2, 10-diazapentacene, a key potential intermediate on the route to a variety of macrocyclic bisbenzylisoquinolines.
- Al-Hiari, Yusuf M.,Bennett, Stephen J.,Cox, Brian,Davies, Robert J.,Khalaf, Abedawn I.,Waigh, Roger D.,Worsley, Alan J.
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p. 647 - 659
(2007/10/03)
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- The Cp2TiMe2-catalyzed intramolecular hydroamination/cyclization of aminoalkynes
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Cp2TiMe2 has been found to be a competent catalyst for the intramolecular hydroamination/cyclization of aminoalkynes. In the presence of 5.0 mol% Cp2TiMe2, the hydroamination reactions proceed smoothly at 100-110°C to give five- and six-membered cyclic imines within 4-6 h. After subsequent reduction performed with zinc-modified NaBH3CN at room temperature cyclic amines can be isolated in good yields.
- Bytschkov, Igor,Doye, Sven
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p. 3715 - 3718
(2007/10/03)
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- Inhibition of dopamine receptors by endogenous amines: Binding to striatal receptors and pharmacological effects on locomotor activity
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Endogenous amine 1-benzyl-1,2,3,4-tetrahydroisoquinoline (1BnTIQ) derivatives are synthesized, and their activity for dopaminergic systems are evaluated in vitro and in vivo by receptor binding assay and pharmacological tests. It is proposed that 1BnTIQ d
- Kawai, Hiroshi,Kotake, Yaichiro,Ohta, Shigeru
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p. 1669 - 1671
(2007/10/03)
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- A highly efficient synthesis of 1-methyl-, 1-benzyl-, and 1-phenyl-1,2,3,4-tetrahydroisoquinolines by a modified pummerer reaction
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(±)-1-Methyl- (13b), (±)-1-benzyl- (13c), and (±)-1-phenyl- (13d)-1,2,3,4-tetrahydroisoquinolines, which are supposed to participate in the pathogenesis of Parkinson's disease, were prepared by using a modified Pummerer reaction as a key step in excellent overall yields from the commercially available ketones (4b-c).
- Shinohara, Tatsumi,Takeda, Akira,Toda, Jun,Terasawa, Noriyo,Sano, Takehiro
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p. 555 - 565
(2007/10/03)
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- Photophysics and photochemistry of intramolecular stilbene-amine exciplexes
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The photophysical and photochemical behavior of a series of trans- (aminoalkyl)stilbenes in which a primary, secondary, or tertiary amine is appended to the stilbene ortho position with a methyl, ethyl, or propyl linker has been investigated. The tertiary
- Lewis, Frederick D.,Bassani, Dario M.,Burch, Eric L.,Cohen, Bliss E.,Engleman, Jeffrey A.,Reddy, G. Dasharatha,Schneider, Siegfried,Jaeger, Wighard,Gedeck, Peter,Gahr, Michael
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p. 660 - 669
(2007/10/02)
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- New strategies for enantioselective syntheses of 1-alkyl- and 1,4-dialkyl-1,2,3,4-tetrahydroisoquinolines: Diastereoselective additions of nucleophiles and electrophiles to isoquinoline mediated by an easily resolved and recycled chiral transition metal auxiliary
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The chiral rhenium isoquinoline complex [(η5-C5H5)Re(NO)(PPh 3)(iso-NC9H7)]+ TfO- (1) and (CH3)3-SiCH2Li give the addition product (η5-C5H5)Re(NO)(PPh3)(N?CH = CHC(CH)4CCHCH2Si(CH3)3) (2) in 71% yield as a 94:6 SS,RR/SR,RS diastereomer mixture. Similar reactions with RMgX (R = (CH3)2CH, CH3CH2, C6H5CH2, CH3(CH2)2, CH3, CH3(CH2)3) give analogous adducts (3-8) as 89-82:11-18 diastereomer mixtures. Reactions of 2 and ROTf (R = H/D, (CH3)3SiCH2, CH3) give alkyl-1,4-dihydroisoquinoline complexes [(η5-C5H5)Re(NO)-(PPh3)(N = CHCHRC(CH)4CCHCH2Si(CH3)3)] + TfO- in 84-72% yields as 94:6 diastereomer mixtures. Related complexes are prepared from 3-5 and HOTf. These react with NaBH4/CH3OH to give alkyl-1,2,3,4-tetrahydroisoquinoline complexes, which are in turn treated with (CH3CH2)4N+ CN- to give (η5-C5H5)Re(NO)(PPh3)(CN) (17) and the title compounds. A reaction sequence starting with (+)-(S)-1 and (CH3)3SiCH2Li yields (+)-(SS)-NHCH2-CH(CH2Si(CH3) 3)C(CH)4CCHCH2Si(CH3)3 (84% overall, 88% ee) and (+)-(S)-17 (82%, >98% ee). Other optically active alkyl tetrahydroisoquinolines are similarly prepared. Complexes 17 and (+)-(S)-17 are converted to (η5-C5H5)Re(NO)(PPh3)(CH 3) (CH3OTf/NaBH4; 88-53%) and thence to 1 or (+)-(S)-1 (92-74%, >98% ee). A crystal structure and other data confirm the configurations assigned to the preceding compounds.
- Richter-Addo, George B.,Knight, D. Andrew,Dewey, Michael A.,Arif, Atta M.,Gladysz
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p. 11863 - 11873
(2007/10/02)
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- Photochemical synthesis of tetrahydrobenzazepines via intramolecular stilbene-amine photoaddition
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The photochemical reactions of several ortho-(aminoalkyl)stilbenes and their N-methyl derivatives have been investigated under conditions of direct and electron-transfer sensitized irradiation and are found to provide an efficient method for the synthesis
- Lewis,Reddy
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p. 4249 - 4252
(2007/10/02)
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- HYDROGENATION OF COMPOUNDS CONTAINING AN INDOLIZINE MOIETY AND OF 1-BENZYLISOQUINOLINE OVER RHENIUM HEPTASULFIDE
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It was shown by hydrogenation of 2,8-diphenylindolizine, benzoindolizine, dibenzoindolizine, dibenzoindolizine, 1-benzylisoquinoline, and 2,3-dimethyl-6-ethyl-4-(4-nitrophenyl)pyridine over Re2S7 (250 deg C, PH2 = 140 atm
- Khorkhe, R. Alarkon,Soldatova, S. A.,Soldatenkov, A. T.,Ryashentseva, M. A.,Prostakov, N. S.
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p. 1253 - 1256
(2007/10/02)
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- Phencyclidine-like Effects of Tetrahydroisoquinolines and Related Compounds
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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.
- Gray, Nancy M.,Cheng, Brian K.,Mick, Stephen J.,Lair, Cecelia M.,Contreras, Patricia C.
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p. 1242 - 1248
(2007/10/02)
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- S-tetrahydroprotoberberineoxidase, process for producing the same and use thereof
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The invention relates to the enzyme S-tetrahydroprotoberberineoxidase, which oxidizes selectively S-tetrahydroprotoberberines and S-1-benzyl-1,2,3,4-tetrahydroisoquinoline in the presence of oxygen, resulting in the corresponding protoberberines and 1-ben
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- TITANIUM(III) INDUCED TRANSFORMATIONS OF N,N-DISUBSTITUTED HYDROXYLAMINES TO IMINES AND SECONDARY AMINES
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The reaction of N,N-disubstituted hydroxylamines with anhydrous TiCl3 gives the corresponding imines, while that with aqueous TiCl3 gives secondary amines.
- Murahashi, Shun-Ichi,Kodera, Yoichi
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p. 4633 - 4636
(2007/10/02)
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- ALKYLATION OF THE ISOQUINOLINE SKELETON IN THE 1-POSITION: LITHIATED 2-PIVALOYL- AND 2-BIS(DIMETHYLAMINO)-PHOSPHINOYL-1,2,3,4-TETRAHYDROISOQUINOLINES
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Nucleophilic reactivity in the 1-position of 1,2,3,4-tetrahydroisoquinoline is generated by lithiation of the N-pivaloyl- (16a) and N-phosphinoyl-derivatives (17a).The organolithium compounds (16b, 17b) thus obtained are highly nucleophilic and can be alkylated even with poor alkylating reagents such as secondary halides, neopentyl bromide and cyclopentanone.Hydrolysis of the phosphorylamide products with hydrochloric acid leads to 1-substituted tetrahydroisoquinolines in excellent yields (Table 2).
- Seebach, Dieter,Lohmann, Jean-Jacques,Syfrig, Max A.,Yoshifuji, Masaaki
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p. 1963 - 1974
(2007/10/02)
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- SYNTHESIS OF DIHYDROISOQUINOLINES AND 1-SUBSTITUTED TETRAHYDROISOQUINOLINES
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A simple synthesis of three dihydroisoquinolines and five 1-substituted tetrahydroisoquinolines from the parent compound involves N-chlorination/dehydrochlorination with KO2 and subsequent organometallation.
- Scully, Frank E.,Schlager, John J.
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p. 653 - 656
(2007/10/02)
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- 2-Bis(dimethylamino)phosphinoyl-1-lithio-1,2,3,4-tetrahydro-isoquinoline. A Highly Nucleophilic d1-Reagent for the Preparation of 1-Substituted Tetrahydroisoquinolines
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The title compound 4 is generated from the phosphoric amide 5 in tetrahydrofuran with butyllithium.The lithium reagent 4 is stable at room temperature; its reactions with electrophiles furnish the products 6-22, 26,27, see Table 1 and the Scheme.A second alkylation is also possible, see 23-25.The cleavage to tetrahydroisoquinolines is accomplished in refluxing aqueous-methanolic hydrochloric acid, see Table 2.Phosphinoylation, lithiation, reaction with electrophiles and cleavage constitute an efficient sequence for 1-alkylation of the isoquinoline nucleus.
- Seebach, Dieter,Yoshifuji, Masaaki
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p. 643 - 647
(2007/10/02)
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- DIPOLE STABILIZED α-AMINO CARBANIONS. II. ALKYLATION OF TETRAHYDROISOQUINOLINES IN THE 1-POSITION.
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N-Formamidine derivatives of tetrahydroisoquinolines are metalated and alkylated to give 1-substituted derivatives.Regeneration of the parent amine is accomplished by several different reagents.
- Meyers, A. I.,Hellring, Stuart,Hoeve, Wolter Ten
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p. 5115 - 5118
(2007/10/02)
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- Mechanism of Formation of Doubly Charged Fragments from Bis-benzyltetrahydroisoquinolines under Electron Impact
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Some bis-benzyltetrahydroisoquinolines give rise to very abundant doubly charged fragment ions under electron impact, corresponding to the loss of the two b
- Bel, Peter,Mandelbaum, Asher
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p. 568 - 572
(2007/10/02)
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