1699-51-0Relevant articles and documents
Berberis alkaloids XXXIX. New alkaloids from B. densiflora
Khamidov,Aripova,Telezhenetskaya,Karimov,Dzhenberov
, p. 323 - 325 (1997)
The alkaloid composition of the leaves of Berberis densiflora has been studied. Berberine, β-allocryptopine, oxyacanthine, glautine, thalicmidine, isocorydine, O-methylcorypalline and the new bases densinine and densiberine have been isolated. The structures of the new alkaloids have been established by a study of spectral characteristics and chemical transformations. This is the first time that any of the known alkaloids, apart from berberine, have been isolated from a plant of this species and it is the first time that β-allocryptopine and O-methylcorypalline have been isolated from the Berberis genus.
Total Synthesis of (-)-Oxycodone via Anodic Aryl-Aryl Coupling
Lipp, Alexander,Selt, Maximilian,Ferenc, Dorota,Schollmeyer, Dieter,Waldvogel, Siegfried R.,Opatz, Till
supporting information, p. 1828 - 1831 (2019/03/07)
A fully regio- and diastereoselective electrochemical 4a-2′-coupling of a 3′,4′,5′-trioxygenated laudanosine derivative enables the synthesis of the corresponding morphinandienone. This key intermediate is further transformed into (-)-oxycodone through conjugate nucleophilic substitution for E-ring closure and [4 + 2] cycloaddition with photogenerated singlet oxygen to accomplish diastereoselective hydroxylation at C-14. The anodic transformation provides high yields and can be performed under constant current conditions both in a simple undivided cell or in continuous flow.
Light-Induced Alkylation of (Hetero)aromatic Nitriles in a Transition-Metal-Free C-C-Bond Metathesis
Lipp, Benjamin,Lipp, Alexander,Detert, Heiner,Opatz, Till
supporting information, p. 2054 - 2057 (2017/04/27)
A light-induced C-C-σ-bond metathesis was achieved through transition-metal-free activation of an unstrained C(sp3)-C(sp3)-σ-bond in 1-benzyl-1,2,3,4-tetrahydroisoquinolines. A photoredox-mediated single-electron oxidation of these precursor amines yield radical cations which undergo a homolytic cleavage of a C(sp3)-C(sp3)-σ-bond rather than the well-known α-C-H-scission. The resulting carbon-centered radicals are used in the ipso-substitution of (hetero)aromatic nitriles proceeding through another single-electron transfer-mediated C-C-bond cleavage and formation.
Total Synthesis of Tetrahydroisoquinoline-Based Bioactive Natural Products Laudanosine, Romneine, Glaucine, Dicentrine, and Their Unnatural Analogues Isolaudanosine and Isoromneine
Jangir, Ravi,Argade, Narshinha P.
, p. 1655 - 1663 (2017/03/21)
Starting from suitably substituted homophthalic acids, total synthesis of titled alkaloids have been demonstrated in very good yields. The obtained natural products laudanosine and romneine were utilized to accomplish synthesis of two isoquinoline-based alkaloids glaucine and dicentrine. Base-induced selective generation of two different types of benzylic carbanions, their coupling reactions with 3,4-dimethoxybenzyl mesylate, and the regioselective iodination followed by intramolecular aryl-aryl coupling reactions to form the fused biaryl systems were the strategic steps.
Synthesis of 1-substituted tetrahydroisoquinolines by lithiation and electrophilic quenching guided by in situ IR and NMR spectroscopy and application to the synthesis of salsolidine, carnegine and laudanosine
Li, Xiabing,Leonori, Daniele,Sheikh, Nadeem S.,Coldham, Iain
, p. 7724 - 7730 (2013/07/19)
The lithiation of N-tert-butoxycarbonyl (N-Boc)-1,2,3,4- tetrahydroisoquinoline was optimized by in situ IR (ReactIR) spectroscopy. Optimum conditions were found by using n-butyllithium in THF at -50 °C for less than 5 min. The intermediate organolithium was quenched with electrophiles to give 1-substituted 1,2,3,4-tetrahydroisoquinolines. Monitoring the lithiation by IR or NMR spectroscopy showed that one rotamer reacts quickly and the barrier to rotation of the Boc group was determined by variable-temperature NMR spectroscopy and found to be about 60.8 kJ mol-1, equating to a half-life for rotation of approximately 30 s at -50 °C. The use of (-)-sparteine as a ligand led to low levels of enantioselectivity after electrophilic quenching and the "poor man's Hoffmann test" indicated that the organolithium was configurationally unstable. The chemistry was applied to N-Boc-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline and led to the efficient synthesis of the racemic alkaloids salsolidine, carnegine, norlaudanosine and laudanosine. Copyright
Synthesis of alkaloids by stevens rearrangement of nitrile-stabilized ammonium ylides: (±)-laudanosine, (±)-laudanidine, (±)-armepavine, (±)-7-methoxycryptopleurine, and (±)-xylopinine
Orejarena Pacheco, Julio Cesar,Lahm, Günther,Opatz, Till
, p. 4985 - 4992 (2013/06/27)
The Stevens rearrangement of nitrile-stabilized ammonium ylides in conjunction with the reductive removal of the nitrile function permits the facile construction of α-branched amines from α-aminonitriles. We employed this reaction sequence for the preparation of (±)-laudanosine, (±)-laudanidine and (±)-armepavine, (±)-7- methoxycryptopleurine, and (±)-xylopinine from two closely related and readily accessible bicyclic α-aminonitriles. The final products were obtained in high to almost quantitative yields (71-98%) from the quaternary ammonium salts obtained by N-alkylation of these starting materials.
A variation of the Pictet-Spengler reaction via a sequential reduction-cyclization reaction of N-acylcarbamates: synthesis of 1-substituted tetrahydroisoquinoline derivatives
Kuhakarn, Chutima,Panyachariwat, Nattakan,Ruchirawat, Somsak
, p. 8182 - 8184 (2008/03/14)
A new variation of the Pictet-Spengler reaction for the synthesis of 1-substituted tetrahydroisoquinoline derivatives has been developed. The reaction employs the reduction of N-acylcarbamates by DIBAL-H followed by simultaneous cyclization mediated by BF3·OEt2. The synthetic potential of this method has been illustrated by the synthesis of the tetrahydroisoquinoline alkaloids, (±)-xylopinine, (±)-laudanosine, (±)-8-oxo-O-methylbharatamine, and (±)-isoindoloisoquinolone.
Potential cancer chemopreventive activity of simple isoquinolines, 1-benzylisoquinolines, and protoberberines
Cui, Wenhua,Iwasa, Kinuko,Tokuda, Harukuni,Kashihara, Akiko,Mitani, Yosuke,Hasegawa, Tomoko,Nishiyama, Yumi,Moriyasu, Masataka,Nishino, Hoyoku,Hanaoka, Miyoji,Mukai, Chisato,Takeda, Kazuyoshi
, p. 70 - 79 (2008/02/04)
Seventeen simple isoquinolines, 15 1-benzylisoquinolines, and 19 protoberberines were tested for their inhibitory activities against Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol- 13-acetate (TPA) in Raji cells. Among the tested alkaloids, the inhibitory activity of all 1-benzylisoquinolines and 11 protoberberines was higher than that of β-carotene. The 1-benzylisoquinolines 19, 21, 22, 29, and 34 and protoberberines 41, 47-49, 51, 52, and 55 showed potent inhibitory effects on EBV-EA induction (96-100% inhibition at 1 × 103 mol ratio/TPA). These alkaloids were more active than the naturally occurring alkaloids, 23, 25, 33, 53, and 54. In addition, fifteen simple isoquinolines, eighteen 1-benzylisoquinolines and eight protoberberines were evaluated with respect to their ability to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals. Nine simple isoquinolines, ten 1-benzylisoquinolines, and four protoberberines were more potent than α-tocopherol, and four 1-benzylisoquinolines, 20 and 28-30, exhibited potent activities (SC50 4.5-5.8 μM). Their activities were higher than the naturally occurring alkaloids, 23, 25, and 33. Therefore, some of the isoquinoline alkaloids indicating the high activity on both assays may be potentially valuable cancer chemopreventive agents. Structure-activity relationships are discussed for both tests.
A convenient synthesis of 1-benzyl-1,2,3,4-tetrahydroisoquinolines by combined Strecker/Bruylants reaction
Reimann, Eberhard,Ettmayr, Christian
, p. 1289 - 1295 (2007/10/03)
Strecker reaction of iodophenethylamines with phenylacetaldehydes afforded the corresponding α-aminonitriles, which on treatment with i-propyl magnesium chloride underwent a Bruylants reaction to give the title compounds. Their structures were deduced by NMR and by an independent preparation starting from papaverine. The educts were easily available by standard procedures. Springer-Verlag 2004.
Syntheses of the seco benzyltetrahydroisoquinoline alkaloids polysignine and methoxypolysignine
Nimgirawath, Surachai
, p. 523 - 525 (2007/10/03)
The structures previously assigned to the seco benzyltetrahydroisoquinoline alkaloids polysignine (1) and methoxypolysignine (2) have been confirmed by total syntheses in which the key step involved cleavage of the C 1-N bonds in the corresponding N-methylbenzyltetrahydroisoquinolines. CSIRO 2000.
