- Synthesis of β-carbolines via a silver-mediated oxidation of tetrahydro-β-carbolines
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The oxidation of tetrahydro-β-carbolines to β-carbolines using silver carbonate was developed as an alternative to current methods. The oxidation is extremely mild and provides the products in modest to good yields after purification. A number of functional groups are tolerated by this methodology, including reduction-sensitive groups which are often cleaved with other methods. Though the mechanism is not fully understood, the reaction proceeds in an open flask, is not sensitive to light or moisture, and provides a viable synthetic route to compounds that are not easily prepared via other methodologies.
- Durham, Sierra D.,Sierra, Brianna,Gomez, Maximillian J.,Tran, Jennifer K.,Anderson, Marc O.,Whittington-Davis, Nick A.,Eagon, Scott
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- Proton-transfer tautomerism of ?2-carbolines mediated by hydrogen-bonded complexes
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The carboxylic acid catalyzed excited-state amino-imino tautomerism for ?2-carboline (?2-CB) and its analogues has been investigated. Thermodynamics and microsolvation (i.e., stoichiometry of the complex formation) of various ?2-CB/acetic acid complexes in nonpolar solvents have been studied by means of absorption and emission titration experiments. Supplementary support of the stoichiometric ratio and structure for the hydrogen-bonding formation was provided by molecular design and syntheses of various ?2-CB analogues incorporating either only one hydrogen bonding site or dual hydrogen bonding sites where interplay between two sites are sterically prohibited. The results in combination with time-resolved measurements and theoretical approaches suggest the 1:2 ?2-CB/acetic acid complex with a structure of triple hydrogen bonding formation to be responsible for the excited-state proton-transfer tautomerism in cyclohexane. The proton transfer time is beyond the response limit of the detecting system of 15 ps, indicating that only a negligibly small geometry adjustment is required for the guest molecule (i.e., acetic acid) to a correct geometry, i.e., a hydrogen-bond relay configuration, for the triple proton transfer to proceed. In comparison, for the 1:1 ?2-CB/acetic acid non-hydrogen-bond relayed complexes, amino-imino tautomerism is prohibited during the excited-state lifetime, giving rise to a normal Stokes shifted emission. The results provide detailed ground-state thermodynamics of ?2-CB HB complexes as well as the dynamics of proton-transfer tautomerism mediated by the hydrogen-bonding structures.
- Chou, Pi-Tai,Liu, Yun-I,Wu, Guo-Ray,Shiao, Mei-Ying,Yu, Wei-Shan,Cheng, Chung-Chih,Chang, Chen-Pin
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- Facile synthesis of isoquinolines, β-carbolines, and 3-deazapurines
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Isoquinoline, β-carbolines, and 3-deazapurines were prepared in 52-81% yields via oxidative decarboxylation of cyclic α-amino acids using ammonium persulfate as an oxidant in the presence of catalytic silver. Copyright Taylor & Francis Group, LLC.
- Huang, Wenhua,Li, Jingyi,Ou, Lihua
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- Selectivity-tunable oxidation of tetrahydro-β-carboline over an OMS-2 composite catalyst: preparation and catalytic performance
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Controlling the reaction selectivity of organic transformations without losing high conversion is always a challenge in catalytic processes. In this work, a H3PO4·12WO3/OMS-2 nanocomposite catalyst ([PW]-OMS-2) was prepared through the oxidation of a Mn(ii) salt with sodium phosphotungstate by KMnO4. Comprehensive characterization indicates that different Mn2+precursors significantly affected the crystalline phase and morphology of the as-synthesized catalysts and only MnSO4·H2O as the precursor could lead to a cryptomelane phase. Moreover, [PW]-OMS-2 demonstrated excellent catalytic activity toward aerobic oxidative dehydrogenation of tetrahydro-β-carbolines due to mixed crystalline phases, enhanced surface areas, rich surface oxygen vacancies and labile lattice oxygen species. In particular, β-carbolines and 3,4-dihydro-β-carbolines could be obtained from tetrahydro-β-carbolines with very high selectivity (up to 99%) over [PW]-OMS-2viatuning the reaction solvent and temperature. Under the present catalytic system, scalable synthesis of a β-carboline was achieved and the composite catalyst showed good stability and recyclability. This work not only clarified the structure-activity relationship of the catalyst, but also provided a practical pathway to achieve flexible, controllable synthesis of functional N-heterocycles.
- Bi, Xiuru,Tao, Luyao,Yao, Nan,Gou, Mingxia,Chen, Gexin,Meng, Xu,Zhao, Peiqing
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p. 3682 - 3692
(2021/03/22)
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- A convenient synthesis of β-carbolines by iron-catalyzed aerobic decarboxylative/dehydrogenative aromatization of tetrahydro-β-carbolines under air
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A convenient synthesis for the conversion of various substituted tetrahydro-β-carbolines has been developed by iron-catalyzed decarboxylative/dehydrogenative aromatization to construct aromatic β-carbolines under air atmosphere. In the presence of a FeCl3 catalyst, this reaction exhibited a good functional group tolerance to produce corresponding β-carbolines in good yields in the absence of any additive. Additionally, the utility of the method was highlighted in the gram-scale synthesis of important natural β-carboline synthons norharmane (2a) and harmane (2b), which the latter provide practical access towards eudistomin N and nostocarboline.
- Mohamad Arshad, Ahmad Saifuddin,Meesala, Ramu,Hanapi, Nur Aziah,Mordi, Mohd Nizam
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- Selective construction of alkaloid scaffolds by alcohol-based direct and mild aerobic oxidative Pictet-Spengler reactions
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Employing TBN/TEMPO as the catalysts and oxygen as the oxidant, the biologically and pharmaceutically significant tetrahydro-β-carboline and β-carboline alkaloid scaffolds that used to be obtained by multi-step processes can now be selectively obtained in only one-stepviadirect aerobic oxidative Pictet-Spengler reactions of tryptamines with alcohols under mild conditions, with water generated as the byproduct. In this reaction, TBN/TEMPO was interestingly found to be able to facilitate the cyclization step of the whole reaction. This method tolerates a variety ofC- andN-substituted tryptamines, and both the more reactive benzylic and allylic alcohols and the less reactive aliphatic alcohols. This method can also be extended to dihydro-β-carboline synthesis and applied to the more available and more economical tryptophan for β-carboline synthesis, revealing its broad substrate scope and potential in synthetic applications.
- Han, Feng,Li, Huan,Liu, Haicheng,Liu, Jianping,Xu, Qing
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p. 7079 - 7085
(2020/10/02)
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- Bifunctional thiosquaramide catalyzed asymmetric reduction of dihydro-β-carbolines and enantioselective synthesis of (-)-coerulescine and (-)-horsfiline by oxidative rearrangement
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Tetrahydro-β-carboline (THBC) is a tricyclic ring system that can be found in a large number of bioactive alkaloids. Herein, we report a simple and efficient method for the synthesis of enantiopure THBCs through a chiral thiosquaramide (11b) catalyzed imine reduction of dihydro-β-carbolines (17a-f). The in situ generated Pd-H employed as hydride source in the reaction of differently substituted chiral THBCs (18a-f) afforded high selectivities (R isomers, up to 96% ee) and good isolated yields (up to 88%). Moreover, the chiral thiosquaramide used also afforded exceptional catalyst activity in the syntheses of (-)-coerulescine (5) and (-)-horsfiline (6) with excellent enantioselectivities up to 98% and 93% ee, respectively, via an enantioselective oxidative rearrangement approach.
- Nachtigall, Fabiane M.,Santos, Leonardo S.,Sathish, Manda
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p. 38672 - 38677
(2020/11/05)
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- Reusable, homogeneous water soluble photoredox catalyzed oxidative dehydrogenation of N-heterocycles in a biphasic system: Application to the synthesis of biologically active natural products
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Herein, a simple and efficient method for the oxidative dehydrogenation (ODH) of tetrahydro-β-carbolines, indolines and tetrahydro-(iso)quinolines is described using a reusable, homogeneous cobalt-phthalocyanine photoredox catalyst in a biphasic medium. A biphasic system offers an advantage of easy separation of the product and an efficient reusability of the homogeneous photoredox catalyst. Also, the current system significantly helps to overcome the solubility issue of the substrate and catalyst at room temperature. Its potential applications to organic transformations are demonstrated by the synthesis of various biologically active N-heterocycles such as indoles, (iso)quinolines and β-carbolines and natural products such as eudistomin U, norharmane, and harmane and precursors to perlolyrine and flazin. Without isolation and purification, the catalyst solution can be reused up to 5 times with almost comparable reactivity. Furthermore, the efficiency of the reaction was demonstrated on a gram scale. To the best of our knowledge, this is the first report on ODH reactions using a non noble, reusable and homogeneous cobalt photoredox catalyst under environmentally friendly conditions.
- Abinaya, R.,Baskar, B.,Mariappan, M.,Prasanth, Arun,Sridhar, R.,Srinath, S.
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p. 2575 - 2587
(2020/05/13)
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- Organic base-promoted efficient dehydrogenative/decarboxylative aromatization of tetrahydro-β-carbolines into β-carbolines under air
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Organic base DBN has been identified as an efficient reagent for promoting the dehydrogenative/decarboxylative aromatization of tetrahydro-β-carbolines under air atmosphere, to access the corresponding β-carbolines in moderate to good yields. The utility of this protocol for the gram-scale synthesis of β-carboline alkaloids eudistomin U (7) and harmane (10) has also been demonstrated.
- Zhao, Ziquan,Sun, Yan,Wang, Lilin,Chen, Xuan,Sun, Yanpei,Lin, Long,Tang, Yulin,Li, Fei,Chen, Dongyin
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p. 800 - 804
(2019/02/16)
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- Organic light-emitting compound, preparation and application thereof and light-emitting device containing organic light-emitting compound
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The invention discloses an organic light-emitting compound. The organic light-emitting compound has a structural formula represented in a following figure. The organic light-emitting compound has chemical stability, and a material containing the organic light-emitting compound has high glass transition temperature and high decomposition temperature, and is an OLED material with excellent performance. The synthetic route of the material has simple and easy operation and high reaction yield, the preparation cost of the OLED material can be reduced, and therefore the material has a good industrialization prospect. The OLED material can be used as a dopant of a light-emitting layer in an organic light-emitting device, effects of high brightness, high efficiency and low voltage can be achievedthrough an organic light-emitting diode prepared by using the OLED material, and screen dark spots can be avoided effectively; and superior performance is achieved.
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- Metal free one pot synthesis of Β-carbolines via a domino Pictet-Spengler reaction and aromatization
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A convenient and efficient metal free, atom economical flexible synthesis of β-carbolines involving a domino Pictet-Spengler reaction and aromatization in oxygen atmosphere in N-methyl-2-pyrollidone (NMP) is described. Variety of aryl, heteroaryl and aliphatic aldehydes were found to be good substrates for this methodology. Several β-carbolines (6a-6t) and β-carboline methyl esters (7a-7e) were synthesized using this methodology.The same reaction carried out in argon atmosphere in the presence of catalytic amount of acid in NMP furnished, tetrahydro-β-carbolines (4a-4g).
- Ramu,Srinath,kumar, A. Aswin,Baskar,Ilango,Balasubramanian
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- Potassium tert-Butoxide-Promoted Acceptorless Dehydrogenation of N-Heterocycles
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Potassium tert-butoxide-promoted acceptorless dehydrogenation of N-heterocycles was efficiently realized for the generation of N-heteroarenes and hydrogen gas under transition-metal-free conditions. In the presence of KOtBu base, a variety of six- and five-membered N-heterocyclic compounds efficiently underwent acceptorless dehydrogenation to afford the corresponding N-heteroarenes and H2 gas in o-xylene at 140 °C. The present protocol provides a convenient route to aromatic nitrogen-containing compounds and H2 gas. (Figure presented.).
- Liu, Tingting,Wu, Kaikai,Wang, Liandi,Yu, Zhengkun
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supporting information
p. 3958 - 3964
(2019/08/01)
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- IBX-mediated oxidative addition of isocyanides to cyclic secondary amines: Total syntheses of alangiobussine and alangiobussinine
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The present study describes a robust and general method for the synthesis of C(1)-carboxamides through IBX-mediated oxidative addition of isocyanides to tryptolines and 1,2,3,4-tetrahydroisoquinolines. In this transformation, IBX plays a dual role of an oxidant and Lewis acid to activate imine facilitating isocyanide addition. Detailed mechanistic investigations were performed by isotopic labeling and real-time NMR experiments. The method was utilized for the gram scale syntheses of two alkaloids alangiobussine and alangiobussinine in 63% and 45% overall yield, respectively.
- Ambule, Mayur D.,Tripathi, Shashank,Ghoshal, Anirban,Srivastava, Ajay K.
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supporting information
p. 10872 - 10875
(2019/09/16)
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- Dehydrogenation of N-Heterocycles by Superoxide Ion Generated through Single-Electron Transfer
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Nitrogen-containing heteroarene motifs are found in numerous pharmaceuticals, natural products, and synthetic materials. Although several elegant methods for synthesis of these compounds through dehydrogenation of the corresponding saturated heterocycles have been reported, some of the methods are hampered by long reaction times, harsh conditions, and the need for catalysts that are not readily available. This work reports a novel method for dehydrogenation of N-heterocycles. Specifically, O2.? generated in situ acts as the oxidant for N-heterocycle substrates that are susceptible to oxidation through a hydrogen atom transfer mechanism. This method provides a general, green route to N-heteroarenes.
- Huang, Yuan-Qiong,Song, Hong-Jian,Liu, Yu-Xiu,Wang, Qing-Min
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p. 2065 - 2069
(2018/01/27)
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- Direct Biomimetic Synthesis of β-Carboline Alkaloids from Two Amino Acids
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The increasing importance of enzyme mimics in organic synthesis inspired us to design a novel biomimetic synthesis of β-carboline alkaloids directly from tryptophan and a second amino acid. This novel one-pot protocol utilizes abundant and readily available starting materials and thus presents a green and user-friendly alternative to conventional methods that rely on stepwise synthesis. Driven by molecular iodine and TFA, decarboxylation, deamination, Pictet-Spengler reaction, and oxidation reactions proceeded sequentially, transforming biomass amino acids into value-added alkaloid motifs.
- Wang, Zi-Xuan,Xiang, Jia-Chen,Cheng, Yan,Ma, Jin-Tian,Wu, Yan-Dong,Wu, An-Xin
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p. 12247 - 12254
(2018/09/21)
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- Cu-catalyzed mild and efficient oxidation of THβCs using air: Application in practical total syntheses of perlolyrine and flazin
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A mild, efficient and environmentally benign method for synthesis of aromatic β-carbolines via Cu(ii)-catalyzed oxidation of 1,2,3,4-tetrahydro-β-carbolines (THβCs) was developed, in which air (O2) was used as the clean oxidant. This method has advantages such as environmentally friendliness, mildness, very good tolerance of functional groups, high yielding and easy experiment operation. In addition, this new methodology was successfully applied in the efficient and practical total syntheses of β-carboline alkaloids perlolyrine and flazin.
- Zheng, Bo,Trieu, Tien Ha,Meng, Tian-Zhuo,Lu, Xia,Dong, Jing,Zhang, Qiang,Shi, Xiao-Xin
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p. 6834 - 6839
(2018/02/23)
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- Iodine-catalyzed chemoselective dehydrogenation and aromatization of tetrahydro-β-carbolines: A short synthesis of Kumujian-C, Eudistomin-U, Norharmane, Harmane Harmalan and Isoeudistomine-M
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Temperature controlled chemoselective dehydrogenation and aromatization of tetrahydro-β-carbolines, using molecular I2 and H2O2, in DMSO solvent affords a practical access to a series of corresponding 3,4-dihydro-β-carbolines and β-carbolines respectively. This method has been successfully employed in the short synthesis of Kumujian-C, Eudistomin-U, Norharmane Harmane Harmalan and Isoeudistomin-M.
- Gaikwad, Sunil,Kamble, Dayanand,Lokhande, Pradeep
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supporting information
p. 2387 - 2392
(2018/05/24)
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- Acceptorless Dehydrogenation of N-Heterocycles and Secondary Alcohols by Ru(II)-NNC Complexes Bearing a Pyrazoyl-indolyl-pyridine Ligand
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Ruthenium(II) hydride complexes bearing a pyrazolyl-(2-indol-1-yl)-pyridine ligand were synthesized and structurally characterized by NMR analysis and X-ray single crystal crystallographic determinations. These complexes efficiently catalyzed acceptorless dehydrogenation of N-heterocycles and secondary alcohols, respectively, exhibiting highly catalytic activity with a broad substrate scope. The present work has established a strategy to construct highly active transition metal complex catalysts and provides an atom-economical and environmentally benign protocol for the synthesis of aromatic N-heterocyclic compounds and ketones.
- Wang, Qingfu,Chai, Huining,Yu, Zhengkun
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p. 584 - 591
(2018/03/08)
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- Green synthesis method for beta-carboline heterocyclic compounds
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The invention discloses a green synthesis method for beta-carboline heterocyclic compounds. The green synthesis method includes that the beta-carboline heterocyclic compounds are made of alcohols compounds, oxidative condensation, cyclization and re-oxidation one-pot cascade reaction is carried out on tryptamines compounds and alcohol in oxygen under the catalytic effects of catalysts TEMPO and catalysts TBN to obtain the beta-carboline heterocyclic compounds, the reaction temperatures range from 40 DEG C to 120 DEG C, and the reaction time ranges from 6 hours to 48 hours. The green synthesismethod has the advantages that inexpensive, easily available, stable and low-toxicity alcohols which can come from wide sources are used as the raw materials for the beta-carboline heterocyclic compounds, the aerobic oxidative condensation, cyclization and re-oxidation cascade reaction is carried out on the tryptamines compounds and the alcohol under the synergistic catalytic effects of the catalysts TEMPO and the catalysts TBN and acetic acid solvent conditions to prepare the beta-carboline heterocyclic compounds, target products are high in selectivity, a byproduct is water, and accordinglythe green synthesis method is high in efficiency and free of pollution.
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Paragraph 0020; 0021; 0022; 0023
(2018/09/11)
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- Cyclometalated beta-carboline ruthenium complex and preparation method and application thereof
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The invention relates to the technical field of antitumor drugs and concretely discloses a cyclometalated beta-carboline ruthenium complex and a preparation method and application thereof. The ruthenium complex takes 1-phenyl-9H-pyrido[3,4-b] indole as a main ligand, and takes 2,2-bipyridyl or 4,4-dimethyl-2,2 bipyridyl as an ancillary ligand. The ruthenium complex has a very excellent anti-tumor effect and has more excellent activity against liver cancer, breast cancer, lung cancer and cervical cancer cell lines than cis-platinum and similar polypyridine carboline ruthenium complexes.
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- Synthesis, characterization, cellular uptake and apoptosis-inducing properties of two highly cytotoxic cyclometalated ruthenium(II) β-carboline complexes
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Two new cyclometalated Ru(II) complexes of the general formula [Ru(N-N)2(1-Ph-βC)](PF6), where N–N = 4,4′-dimethyl-2,2′-bipyridine (dmb, Ru1), 2,2′-bipyridine (bpy, Ru2), and 1-Ph-βC (1-phenyl-9H-pyrido[3,4-b]indole) is a β-carboline alkaloids derivatives, have been synthesized and characterized. The in vitro cytotoxicities, cellular uptake and localization, cell cycle arrest and apoptosis-inducing mechanisms of these complexes have been extensively explored by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, inductively coupled plasma mass spectrometry (ICP-MS), flow cytometry, comet assay, inverted fluorescence microscope as well as western blotting experimental techniques. Notably, Ru1 and Ru2 exhibit potent antiproliferative activities against selected human cancer cell lines with IC50 values lower than those of cisplatin and other non-cyclometalated Ru(II) β-carboline complexes. The cellular uptake and localization exhibit that these complexes can accumulate in the cell nuclei. Further antitumor mechanism studies show that Ru1 and Ru2 can cause cell cycle arrest in the G0/G1 phase by regulating cell cycle relative proteins and induce apoptosis through mitochondrial dysfunction, reactive oxygen species (ROS) accumulation and ROS-mediated DNA damage.
- Chen, Jincan,Peng, Fa,Zhang, Yao,Li, Baojun,She, Ji,Jie, Xinming,Zou, Zhilin,Chen, Man,Chen, Lanmei
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p. 104 - 117
(2017/09/20)
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- Synthesis and application of β-carbolines as novel multi-functional anti-Alzheimer's disease agents
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The design, synthesis and assessment of β-carboline core-based compounds as potential multifunctional agents against several processes that are believed to play a significant role in Alzheimer's disease (AD) pathology, are described. The activity of the compounds was determined in Aβ self-assembly (fibril and oligomer formation) and cholinesterase (AChE, BuChE) activity inhibition, and their antioxidant properties were also assessed. To obtain insight into the mode of action of the compounds, HR-MS studies were carried out on the inhibitor-Aβ complex formation and molecular docking was performed on inhibitor-BuChE interactions. While several compounds exhibited strong activities in individual assays, compound 14 emerged as a promising multi-target lead for the further structure-activity relationship studies.
- Horton, William,Sood, Abha,Peerannawar, Swarada,Kugyela, Nandor,Kulkarni, Aditya,Tulsan, Rekha,Tran, Chris D.,Soule, Jessica,LeVine, Harry,T?r?k, Béla,T?r?k, Marianna
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p. 232 - 236
(2016/12/27)
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- A new approach to 1-substituted β-carbolines and isoquinolines utilizing tributyl[(Z)-2-ethoxyvinyl]stannane as a C-3,C-4 building block
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Starting from readily available indole-2-carboxylic acids, 1-substituted β-carbolines (among them the alkaloids harmane and isoharmine) are readily obtained via the corresponding 2-acylindoles, bromination at C-3, followed by a one-pot Stille cross-coupling with tributyl[(Z)-2-ethoxyvinyl]stannane, and ring closure with ammonium acetate. 1-Substituted isoquinolines are available in an analogous manner starting from 2-bromobenzoic acid.
- Kamlah, Alexandra,Lirk, Florian,Bracher, Franz
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p. 837 - 845
(2016/01/20)
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- Iodine-catalyzed one-pot decarboxylative aromatization of tetrahydro-β-carbolines
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A synthetic strategy was developed for the preparation of β-carbolines by one-pot decarboxylation and aromatization of tetrahydro-β-carboline-3-carboxylic acids by employing 10?mol% of iodine in presence of oxidant aqueous H2O2. The method was also successfully extended for the aromatization of tetrahydro-β-carboline-3-methyl esters. The utility of the method was demonstrated in the synthesis of β-carboline alkaloids norharmane, harmane and eudistomin N.
- Meesala, Ramu,Arshad, Ahmad Saifuddin Mohamad,Mordi, Mohd Nizam,Mansor, Sharif Mahsufi
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p. 8537 - 8541
(2016/12/09)
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- Dehydrogenation of 1-aryl(hetaryl)-1,2,3,4-tetrahydro-9H-β-carboline-3-carboxylic acids and their esters with dimethyl sulfoxide
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Oxidative dehydrogenation of 1-aryl(hetaryl)-1,2,3,4-tetrahydro-9Н-β-carboline-3-carboxylic acids derivatives with dimethyl sulfoxide leads to the formation of 1-aryl(hetaryl)-9Н-β-carbolines. Simultaneously with the dehydrogenation decarboxylation occurs
- Abramyants,Lomov,Zavyazkina
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p. 1610 - 1615
(2017/01/28)
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- Synthesis of tetrahydro-β-carbolines, β-carbolines, and natural products, (±)-harmicine, eudistomin U and canthine by reductive Pictet Spengler cyclization
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Reductive Pictet Spengler cyclization was used for the synthesis of naturally occurring β-carbolines, eudistomin U, and canthine. Other biologically important β-carbolines as well as tetrahydro-β-carboline, such as (±)-harmicine were also synthesized usin
- Pakhare, Deepali S.,Kusurkar, Radhika S.
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p. 6012 - 6015
(2015/10/28)
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- Ru(II)-catalyzed β-carboline directed C-H arylation and isolation of its cycloruthenated intermediates
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A Ru(II)-catalyzed C-H arylation approach has been developed utilizing β-carboline alkaloids as the directing group. Selective formations of diarylated products from moderate to excellent yields were accomplished. Broad substrate scope with excellent functional group tolerance for C1-phenyl/thienyl/PAHs-β-carbolines was demonstrated. X-ray crystal structure of cycloruthenated complex 2cr and no arylation reaction with model substrate 13 strongly suggests that N2 is the directing group than N9 in C1-aryl-β-carbolines. Catalytic properties and stability of the cycloruthenated complexes have been explored. Library of biologically relevant new β-carboline derivatives and isolation of its cycloruthenated intermediates are the highlights of this work.
- Rajkumar, Subramani,Karthik, Shanmugam,Gandhi, Thirumanavelan
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p. 5532 - 5545
(2015/06/16)
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- An efficient one-pot decarboxylative aromatization of tetrahydro-β-carbolines by using N-chlorosuccinimide: total synthesis of norharmane, harmane and eudistomins
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A facile method for the synthesis of a variety of β-carbolines and their natural products such as norharmane (2a), harmane (2b), eudistomins I, N, T, and U (6, 7, 9 and 10, respectively) has been successfully developed via a decorboxylative aromatization tool by employing N-chlorosuccinimide (NCS) as a mild and efficient reagent. Gratifyingly, this reagent system proceeds in a one-pot manner and converted all the tetrahydro-β-carboline acids into their corresponding decorboxylative aromatic products with good to excellent yields. Additionally, this system works well in the case of tetrahydro-β-carboline esters to produce their aromatic partners in high yields.
- Kamal, Ahmed,Sathish, Manda,Prasanthi,Chetna, Jadala,Tangella, Yellaiah,Srinivasulu, Vunnam,Shankaraiah, Nagula,Alarifi, Abdullah
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p. 90121 - 90126
(2015/11/10)
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- PhI(OAc)2-mediated one-pot oxidative decarboxylation and aromatization of tetrahydro-β-carbolines: Synthesis of norharmane, harmane, eudistomin U and eudistomin i
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Iodobenzene diacetate was employed as a mild and efficient reagent for one-pot oxidative decarboxylation of tetrahydro-β-carboline acids and dehydrogenation of tetrahydro-β-carbolines to access the corresponding aromatic β-carbolines. To the best of our knowledge this is the first synthesis of β-carbolines via a one-pot oxidative decarboxylation at ambient temperature. The utility of this protocol has been demonstrated in the synthesis of β-carboline alkaloids norharmane (2o), harmane (2p), eudistomin U (9) and eudistomin I (12).
- Kamal, Ahmed,Tangella, Yellaiah,Manasa, Kesari Lakshmi,Sathish, Manda,Srinivasulu, Vunnam,Chetna, Jadala,Alarifi, Abdullah
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p. 8652 - 8662
(2015/08/24)
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- Decarboxylative aromatization of β-carbolines by using metal free catalysis and efficient synthesis of β-carboline derivatives
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A new novel metal-free decarboxylative and aromatized β-carboline (5a-j) derivatives were synthesized by one-pot reaction. In all cases, resulting β-carboline derivatives with above 90 % yield.
- Rao, Chunduru Srinivasa,Reddy, Ch. Venkata Ramana,Devi, B. Rama,Vantikommu, Jyothi,Cherukuri, Jyotna,Sait, Shakil S.
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p. 4701 - 4702
(2015/11/27)
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- Microwave-Assisted Synthesis of Tetrahydro-β-carbolines and β-Carbolines
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A microwave-mediated Pictet-Spengler procedure utilizing 1,2-dichloroethane (DCE) and trifluoroacetic acid (TFA) was developed to provide tetrahydro-β-carboline salts in high yields. Reactions are complete in 20 minutes or less and the product precipitates from solution in high yields and purity, negating the need for liquid-liquid extraction or column chromatography. This method tolerates a wide range of functionality and can be performed on milligram to gram scales. A subsequent microwave-mediated aromatization of the synthesized tetrahydro-β-carbolines to β-carbolines was also developed utilizing catalytic Pd/C. The aromatization is complete in 60 min or less with most substrates requiring minimal purification. A microwave-assisted Pictet-Spengler procedure was developed to afford tetrahydro-β-carboline salts in high yields with no liquid-liquid extraction or chromatography required. A subsequent microwave-assisted aromatization procedure was also developed to provide β-carbolines in high yields requiring limited purification.
- Eagon, Scott,Anderson, Marc O.
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p. 1653 - 1665
(2015/10/05)
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- Copper-catalyzed protodecarboxylation and aromatization of tetrahydro-β-carboline-3-carboxylic acids
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An efficient synthetic methodology has been developed to construct aromatic β-carbolines from tetrahydro-β-carboline-3-carboxylic acids by copper-promoted sequential decarboxylation and oxidative aromatization. Georg Thieme Verlag Stuttgart · New York.
- Meesala, Ramu,Mordi, Mohd Nizam,Mansor, Sharif Mahsufi
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p. 120 - 122
(2014/01/06)
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- Energy efficiency of heterogeneous catalytic microwave-assisted organic reactions
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The energy efficiency of microwave-assisted reactions was studied under heterogeneous catalytic conditions. Based on earlier publications the choice of catalyst was a semi-synthetic montmorillonite K-10. This material absorbs microwave energy effectively and is an excellent catalyst for microwave-assisted organic synthesis. The energy consumption of six different types of K-10 catalyzed reactions with multiple substrates and varied experimental parameters were determined under microwave irradiation and conventional heating. The parallel reactions were carried out under the same conditions to ensure the comparability of the data. While in the majority of the studied reactions, the microwave-assisted method appeared to be more energy efficient by various extents, in one case the conventional heating was found to be more efficient. The data, in agreement with a previous report, indicate that reactions should be studied on a case-by-case basis and that an automatic green label for microwave-assisted reactions is not warranted. This journal is the Partner Organisations 2014.
- Cho, Hyejin,Toeroek, Fanni,Toeroek, Bela
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p. 3623 - 3634
(2014/07/08)
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- Synthesis and structure-activity relationships of N2-alkylated quaternary β-carbolines as novel antitumor agents
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A series of novel N2-alkylated quaternary β-carbolines was synthesized by modification of position-1, 2, 7 and 9 of β-carboline nucleus with various alkyl and arylated alkyl substituents, and their cytotoxic activities in vitro and antitumor potencies in mice were evaluated. Compound 3m was found to be the most potent antitumor agent. SARs analysis revealed that (1) the substituents in position-2 and 9 of β-carboline nucleus played a vital role in modulation of antitumor activity; (2) the benzyl and 3-phenylpropyl substituents in position-2 and 9 of β-carboline ring were the optimal substituents giving rise to significant antitumor agent. These compounds might be a novel promising class of antitumor agents with clinical development potential.
- Zhang, Guoxian,Cao, Rihui,Guo, Liang,Ma, Qin,Fan, Wenxi,Chen, Xuemei,Li, Jianru,Shao, Guang,Qiu, Liqin,Ren, Zhenghua
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- Acceptorless dehydrogenation of nitrogen heterocycles with a versatile iridium catalyst
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Gas up: A cyclometalated iridium complex is found to catalyze the dehydrogenation of various benzofused N-heterocycles, thus releasing H 2. Driven by as low as 0.1 mol % catalyst, the reaction affords quinolines, indoles, quinoxalines, isoquinolines, and β-carbolines in high yields. Copyright
- Wu, Jianjun,Talwar, Dinesh,Johnston, Steven,Yan, Ming,Xiao, Jianliang
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supporting information
p. 6983 - 6987
(2013/07/26)
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- Total syntheses of eudistomins Y1-Y7 by an efficient one-pot process of tandem benzylic oxidation and aromatization of 1-benzyl-3,4-dihydro-β-carbolines
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The first total synthesis of eudistomin Y7 (7) and total syntheses of eudistomins Y1-Y6 (1-6) are described. An efficient room-temperature conversion of 1-benzyl-3,4-dihydro-β-carbolines (11) into 1-benzoyl-β-carbolines (14) by a one-pot process of tandem benzylic oxidation and aromatization as the key step of these total syntheses was also studied in detail. The first total synthesis of eudistomin Y 7 (7) and total syntheses of eudistomins Y1-Y6 (1-6) are described. An efficient room-temperature conversion of 1-benzyl-3,4-dihydro-β-carbolines (11) into 1-benzoyl-β-carbolines (14) by a one-pot process of tandem benzylic oxidation and aromatization as the key step of these total syntheses was also studied in detail. Copyright
- Trieu, Tien Ha,Dong, Jing,Zhang, Qiang,Zheng, Bo,Meng, Tian-Zhuo,Lu, Xia,Shi, Xiao-Xin
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supporting information
p. 3271 - 3277
(2013/07/05)
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- Efficient and practical one-pot conversions of n- tosyltetrahydroisoquinolines into isoquinolines and of N-tosyltetrahydro-β- carbolines into β-carbolines through tandem β-elimination and aromatization
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An efficient, practical, and general method for conversions of N-tosyltetrahydroisoquinolines (N-tosyl-THIQs) into isoquinolines and of N-tosyltetrahydro-β-carbolines (N-tosyl-THBCs) into β-carbolines is described. Treatment of N-tosyl-THIQs or N-tosyl-THBCs with base in dimethyl sulfoxide afforded dihydroisoquinolines or dihydro-β-carbolines as intermediates, and these were then oxidized in situ by molecular oxygen to furnish isoquinolines or β-carbolines in good to high yields. Both one-pot conversions occurred through tandem β-elimination and aromatization. An efficient method for conversions ofN-tosyltetrahydroisoquinolines (N-tosyl-THIQs) and N-tosyltetrahydro-β-carbolines (N-tosyl-THBCs) into isoquinolines and β-carbolines is described. Treatment ofN-tosyl-THIQs or N-tosyl-THBCs with base affords dihydroisoquinolines or dihydro-β- carbolines. These can be oxidized in situ by molecular oxygen to furnish isoquinolines or β-carbolines. Copyright
- Dong, Jing,Shi, Xiao-Xin,Yan, Jing-Jing,Xing, Jing,Zhang, Qiang,Xiao, Sen
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experimental part
p. 6987 - 6992
(2011/02/24)
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- Room-temperature aromatization of tetrahydro-β-carbolines by 2-iodoxybenzoic acid: Utility in a total synthesis of eudistomin U
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2-Iodoxybenzoic acid is a convenient reagent for the dehydrogenation of tetrahydro-β-carbolines to their aromatic forms under mild conditions. The utility of the method was demonstrated in a total synthesis of the marine indole alkaloid eudistomin U.
- Panarese, Joseph D.,Waters, Stephen P.
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scheme or table
p. 4086 - 4089
(2010/11/16)
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- An alternative to pictet-gams reaction triggered by hendrickson reagent: Isoquinolines and β-carbolines from amides
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The Hendrickson reagent derived from triflic anhydride and triphenylphosphine oxide exhibited high oxophilicity and induced the intramolecular cyclization of β-arylethylamides perfectly. Thus, a one-pot protocol to access isoquinoline and β-carboline was developed involving cyclization followed by oxidative aromatization. Georg Thieme Verlag Stuttgart · New York.
- Wu, Mengde,Wang, Shaozhong
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experimental part
p. 587 - 592
(2010/04/24)
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- A direct synthesis of β-carbolines via a three-step one-pot domino approach with a bifunctional Pd/C/K-10 catalyst
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A rapid, microwave-assisted synthesis of β-carbolines via a successive condensation/cyclization/dehydrogenation approach is described. This methodology involves the coupling of various tryptamines with aromatic aldehydes/glyoxals. The product imine underg
- Kulkarni, Aditya,Abid, Mohammed,T?r?k, Béla,Huang, Xudong
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scheme or table
p. 1791 - 1794
(2009/07/19)
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- A simple method for the synthesis of 1-substituted β-carboline derivatives from tryptamine and carboxylic acids in polyphosphoric acid
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A number of 1-substituted 3,4-dihydro-9H-β-carboline derivatives (4) with high purity and yields have been synthesized by treating of tryptamine (1) with carboxylic acids (2) in polyphosphoric acid. 3,4-Dihydro-9H-β-carbolines (4) were successfully transformed to 1,2,3,4-tetrahydro-9H-β-carbolines (5) and 9H-β-carbolines (6).{A figure is presented}.
- Ivanov, Iliyan,Nikolova, Stoyanka,Statkova-Abeghe, Stela
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p. 2483 - 2492
(2007/10/03)
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- Efficient one-pot synthesis of anti-HIV and anti-tumour β-carbolines
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Thermal electrocyclisation of the azahexatriene system has been used as a key step for the synthesis of anti-HIV and anti-tumour compounds, harman, derivatives of harman and 1-aryl-β-carbolines. A one-pot reaction sequence was used to furnish these compounds in good yield.
- Kusurkar, Radhika S.,Goswami, Shailesh K.
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p. 5315 - 5318
(2007/10/03)
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- β-Carbolines as specific inhibitors of cyclin-dependent kinases
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Harmine (3), 7-fluoro-1-methyl β-carboline (35) and 1-(5-methyl-imidazol-4-yl) β-carboline (41) were potent and specific inhibitors of cyclin-dependent kinases. The degree of aromaticity of the tricyclic ring and the positioning of substituents are important for inhibitory activity. While most β-carbolines inhibited CDK2 and CDK5 to the same extent, selective inhibition against CDK2 was observed in 1-(2-chlorophenyl)- (12), 1-(2-fluorophenyl)- (15), and 1-(2-chloro-5-nitrophenyl)- (28) β-carbolines.
- Song, Yongcheng,Wang, Jian,Teng, Su Fern,Kesuma, Djohan,Deng, Yu,Duan, Jinao,Wang, Jerry H.,Qi, Robert Zhong,Sim, Mui Mui
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p. 1129 - 1132
(2007/10/03)
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- Synthesis and platelet aggregation inhibitory effects of harman and phthalide derivatives related to ligusticum chuanxiong (Hort.) constituents
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The Chinese drug plant Ligusticum chuanxiong (Hort.) has platelet aggregation inhibiting effects, and also protects against sub-lethal radiation doses that cause capillary hypercoagulation. Two types of derivatives of known constituents of this plant have been synthesized and tested for inhibition of hypercoagulation. These include harman and phthalide derivatives. The harman derivatives showed good inhibitory effects against platelet aggregation in rabbit heart blood ranging from 39-96%. The phthalides gave 0-19% inhibitions.
- Foye, William O.,Wang, Xiping,Hongfu, Wang
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p. 180 - 191
(2007/10/03)
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- Mild Oxidation of 1,2,3,4-Tetrahydro-β-carbolines
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Oxidation of 1-(aryl or heteroaryl)-1,2,3,4-tetrahydro-β-carbolines (1a-r) with KMnO4 in dry THF afforded in the most cases almost exclusively 3,4-dihydro products (2) with a yield of 28-94percent.Only in few cases (1c, 1i, 1m) the reaction was non-selective and a significant amount of the fully aromatized products (3) (30-40percent of the reaction mixture) was observed.The influence of both the substituent nature and the substitution modes on the observed yield and selectivity of the reaction was discussed.Key words: 1,2,3,4-tetrahydro-β-carbolines, 3,4-dihydro-β-carbolines, selective oxidation, oxidation with KMnO4 in cold THF, substituent effect
- Mokrosz, M.J.,Paluchowska, M.H.,Misztal, S.
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p. 264 - 268
(2007/10/02)
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- A new convergent synthesis of alpha-substituted-beta-carbolines
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New convergent synthesis of natural α-substituted-β-carbolines through metalations, cross-couplings and intramolecular substitutioin via (2-aminobenzene)-boronic acid, arylstannanes and ortho-fluoroiodopyridines.
- Rocca,Marsais,Godard,Queguiner
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p. 3325 - 3342
(2007/10/02)
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- β-Carboline Alkaloids, I. - Syntheses of 1-Aryl and 1-Alkenyl-β-carbolines by Palladium-Catalyzed Coupling Reactions
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1-Chloro-β-carboline (6) is prepared in three steps starting from tryptamine (3).Palladium-catalyzed coupling reactions of 6 with aryl boronic acids offer an easy access to the alkaloids komaroine (11) and perlolyrine (15).Pavettine (16) is prepared by co
- Bracher, Franz,Hildebrand, Dirk
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p. 1315 - 1320
(2007/10/02)
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