- Effect of isoquinoline alkaloids of different structural types on antiplatelet aggregation in vitro
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Forty-one isoquinoline alkaloids were tested for antiplatelet aggregation effects. Among them, (-)-discretamine (6), protopine (7), ochotensimine (18), O-methylarmepavinemethine (23), lindoldhamine (25), isotetrandrine (26), thalicarpine (27), papaverine (28), and D-(+)-N-norarmepavine (32) exhibited significant inhibitory activity towards adenosine 5′-diphosphate (ADP)-, arachidonic acid (AA)-, collagen-, and/or platelet-activating factor (PAF)-induced platelet aggregation. The results are discussed on the basis of structure-activity relationships. Georg Thieme Verlag KG Stuttgart.
- Chia, Yi-Chen,Chang, Fang-Rong,Wu, Chin-Chung,Teng, Che-Ming,Chen, Keh-Shaw,Wu, Yang-Chang
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- Dehatrine, an antimalarial bisbenzylisoquinoline alkaloid from the Indonesian medicinal plant Beilschmiedia madang, isolated as a mixture of two rotational isomers
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Through bioassay-guided separations of the chemical constituents of the Indonesian medicinal plant Beilschmiedia madang BL. A bisbenzylisoquinoline alkaloid was obtained as the major antimalarial principle. The physicochemical properties of the alkaloid were consistent with the proposed structure of dehatrine (1). However, the alkaloid isolated by us was shown to be a mixture of two rotational isomers. The X-ray crystallographic analysis of 1 has shown that two rotamers are incorporated in a single crystal 1:1 ratio. The complex NMR spectrum of 1 has also been defined as a mixture of two rotamers by extensive use of 2D (COSY and COLOC) techniques. Dehatrine (1) has been shown to significantly inhibit the growth of cultured Plasmodium falciparum K1 strain (chloroquine resistant) with similar activity to quinine.
- Kitagawa,Minagawa,Zhang,Hori,Doi,Inoue,Ishida,Kimura,Uji,Shibuya
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Read Online
- Light-Induced Alkylation of (Hetero)aromatic Nitriles in a Transition-Metal-Free C-C-Bond Metathesis
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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.
- Lipp, Benjamin,Lipp, Alexander,Detert, Heiner,Opatz, Till
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supporting information
p. 2054 - 2057
(2017/04/27)
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- Enantioselective Oxidative Aerobic Dealkylation of N-Ethyl Benzylisoquinolines by Employing the Berberine Bridge Enzyme
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N-Dealkylation methods are well described for organic chemistry and the reaction is known in nature and drug metabolism; however, to our knowledge, enantioselective N-dealkylation has not been yet reported. In this study, exclusively the (S)-enantiomers o
- Gandomkar, Somayyeh,Fischereder, Eva-Maria,Schrittwieser, Joerg H.,Wallner, Silvia,Habibi, Zohreh,Macheroux, Peter,Kroutil, Wolfgang
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p. 15051 - 15054
(2016/01/25)
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- Synthesis of (+)-O-methylthalibrine by employing a stereocontrolled Bischler-Napieralski reaction and an electrochemically generated diaryl ether
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An efficient electrochemical four-step route was developed for the preparation of diaryl ether derivatives by using halogenation and dehalogenation processes in addition to electrochemical phenolic oxidation and reduction reactions. The synthesis of (+)-O
- Kawabata, Yuki,Naito, Yu,Saitoh, Tsuyoshi,Kawa, Kohei,Fuchigami, Toshio,Nishiyama, Shigeru
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- Practical metal-free C(sp3)-H functionalization: Construction of structurally diverse α-substituted N-benzyl and N-allyl carbamates
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Described is a practical and universal C-H functionalization of readily removable N-benzyl and N-allyl carbamates, with a wide range of nucleophiles at ambient temperature promoted by Ph3CClO4. The metal-free reaction has an excellent functional-group tolerance, and displays a broad scope with respect to both N-carbamates and nucleophile partners (a variety of organoboranes and C-H compounds). The synthetic utility in target- as well as diversity-oriented syntheses is demonstrated. Strategic play: A direct functionalization of the title carbamates with a wide range of nucleophiles has been developed. The reaction proceeds efficiently at low temperature using Ph3CClO4 as an oxidant. Sensitive functional groups are tolerated, thus allowing applications in natural product synthesis, the construction of chemical libraries, and the discovery of potential anticancer targets.
- Xie, Zhiyu,Liu, Lei,Chen, Wenfang,Zheng, Hongbo,Xu, Qingqing,Yuan, Huiqing,Lou, Hongxiang
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supporting information
p. 3904 - 3908
(2014/05/06)
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- A new benzylisoquinoline alkaloid from Argemone mexicana
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A new benzylisoquinoline alkaloid, argemexirine, together with two known protoberberine alkaloids, dl-tetrahydrocoptisine and dihydrocoptisine, have been isolated from the methanolic extract of the whole plant of Argemone mexicana L. The compounds were identified by spectral and chemical evidence. This is the first report of these alkaloids in this plant species.
- Singh, Sarita,Singh,Singh,Pandey
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experimental part
p. 63 - 67
(2010/04/23)
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- Method and health food for preventing and/or alleviating psychiatric disorder, and/or for effectuating sedation
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A method for preventing and/or alleviating a psychiatric disorder, and/or effectuating sedation, comprising administering a benzylisoquinoline derivative represented by General Formula (I): wherein R1, R2, R3 and X each re
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Page/Page column 9
(2008/06/13)
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- A novel straightforward synthesis of enantiopure tetrahydroisoquinoline alkaloids
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A novel, direct, and high-yielding stereoselective method for enantiopure 1-substituted tetrahydroisoquinolines (THIQ) is described. The successful approach, which creates the stereocenter during the formation of the THIQ nucleus is based on (i) formation of chiral 2,3-substituted perhydro-1,3-benzoxazines derived from (-)-8-aminomenthol, (ii) diastereoselective intramolecular ring opening of the N,O-acetal moiety by an arylmetal generated from the substituent at the nitrogen atom in the perhydrobenzoxazine ring, and (iii) removal of the chiral auxiliary appendage. The starting perhydrobenzoxazines are easily prepared from (-)-8-aminomenthol and two different aldehydes, and the intramolecular opening is stereospecific, leading to a single stereoisomer. The method allows the preparation of a wide variety of enantiopure 1-substituted THIQ, with different substituents at C-1, by changing the nature of the starting aldehydes.
- Pedrosa,Andres,Iglesias
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p. 243 - 250
(2007/10/03)
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- Syntheses of the seco benzyltetrahydroisoquinoline alkaloids polysignine and methoxypolysignine
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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.
- Nimgirawath, Surachai
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p. 523 - 525
(2007/10/03)
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- Lewis acid-mediated nucleophilic alkylations on chiral [6,3a,4]oxadiazaindano[5,4-a]isoquinolines. Asymmetric synthesis of 1-alkyl substituted tetrahydroisoquinolines
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Lewis acid-mediated nucleophilic alkylation of the chiral [6,3a,4]oxadiazaindano[5,4-a]isoquinoline derivatives with various organometallic reagents leads to highly enantioselective synthesis of 1-alkyl substituted tetrahydroisoquinolines. This methodology was applied to the asymmetric synthesis of (-)-salsolidine and (+)-O-methylarmepavine.
- Yamazaki, Naoki,Suzuki, Hideaki,Aoyagi, Sakae,Kibayashi, Chihiro
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p. 6161 - 6164
(2007/10/03)
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- ALKALOIDS OF DEHAASIA TRIANDRA
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Separation of the basic fraction from Dehaasia triandra afforded two new bisbenzylisoquinoline alkaloids, dehatridine and dehatrine, along with six known alkaloids, isocorydine, corytuberine, atheroline, nantenine, obaberine and a quaternary aporphine alkaloid, xanthoplanine (5). - Keywords: Dehaasia triandra; Lauraceae; Iau-Guoo-Nan; bisbenzylisoquinoline alkaloids; dehatridine; dehatrine.
- Lu, Sheng-Teh,Tsai, Ian-Lih,Leou, Shiow-Piaw
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p. 615 - 620
(2007/10/02)
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- ENZYMIC CONTROL OF STEREOCHEMISTRY AMONG THE THALICTRUM BISBENZYLISOQUINOLINE ALKALOIDS
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The new bisbenzylisoquinolines (+)-thaligrisine and (+)-thaliphylline 6 have been isolated from Thalictrum minus var. microphyllum.Four rules are described which correlate the structures os Thalictrum bisbenzylisoquinolines with their stereochemistry at C-1 and C-1'.As a result, (+)-thalrugosamine is shown to be identical with (+)-homoaromoline 14. (+)-Thalisamine and (+)-N'-norhernandezine are also identical and are represented by expression 18.The sole exception to the rules is (-)-isothalidezine 15.
- Guinaudeau, Helene,Freyer, Alan J.,Shamma, Maurice,Baser, Kemal Husnu Can
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p. 1975 - 1982
(2007/10/02)
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- Novel Biogenetic Pathways from (+)-Reticuline. Three Dimeric Alkaloids: (+)-Vanuatine, (+)-Vateamine, and (+)-Malekulatine
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The bark of Hernandia peltata Meissner (Hernandiaceae), gathered in the Republic of Vanuatu (New Hebrides), has yielded the bis(benzylisoquinolines) (+)-vanuatine (5), (+)-vateamine (6), and (+)-malekulatine (7).These are the first-known dimers of (+)-reticuline (2).Compounds 5 and 6 are products of tail-to-tail oxidative coupling, whereas 7 involves head-to-tail coupling.
- Bruneton, Jean,Shamma, Maurice,Minard, Robert D.,Freyer, Alan J.,Guinaudeau, Helene
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p. 3957 - 3960
(2007/10/02)
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- Novel Zinc-Promoted Alkylation of Iminium Salts. New Synthesis of Benzylisoquinoline, Phthalidylisoquinoline, and Protoberberine Alkaloids and Related Compounds
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Zinc-promoted reductive coupling reaction of iminium salts with alkyl halides was found to be a successful key reaction for synthesis of a variety of alkaloids such as benzylisoquinoline, phthalidylisoquinoline, and protoberberine alkaloids.More specifically, laudanosine, cordrastine, hydrastine, narcotine, tetrahydropalmatine, and canadine were obtained.A new route for the synthesis of the emetine and yohimbine skeletons was exploited.
- Shono, Tatsuya,Hamaguchi, Hiroshi,Sasaki, Manji,Fujita, Shumei,Nagami, Kimihiko
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p. 1621 - 1628
(2007/10/02)
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- SYTHESIS OF N-(ARYLETHYL)ARYLTHIOACETAMIDES BY THE WILLGERODT-KINDLER REACTION AND THEIR CONVERSION TO SUBSTITUTED 1-BENZYL-1,2,3,4-TETRAHYDROISOQUINOLINES
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N-(Arylethyl)arylthioacetamides were synthesized by the reaction of substituted acetophenones with 2-arylethylamines.The reaction gives good yields when compounds with substituted hydroxyl groups are used. 2,4-Diarylthiazoles were isolated as side products from the Wilgerodt-Kindler reaction.The thioamides were converted into substituted 1-benzyl-1,2,3,4-tetrahydroisoquinolines by the Bischler-Napieralski cyclization, N-methylation, and reduction of the corresponding 3,4-dihydroisoquinoline methiodide derivatives.
- Nakova, E.P.,Tolkachev, O.N.,Evstigneeva, R.P.
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p. 550 - 555
(2007/10/02)
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