139655-06-4

Upstream product

• 155880-53-8 1-(p-Methoxyphenyl)-2-(p-toluenesulfonyl)-1,2-dihydro-β-carboline 
• 82789-20-6 1-(4-methoxyphenyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole-3-carboxylic acid 
• 82980-12-9 3-ethenyl-1-phenylsulfonyl-1H-indole 
• 874-90-8 4-methoxybenzonitrile 
• 123-11-5 4-methoxy-benzaldehyde 
• 14674-38-5 N-(4-methoxybenzylidene)-p-toluenesulfonamide 
• 296797-76-7 2,3,4,9-tetrahydro-1-(4-methoxyphenyl)-2-tosyl-1H-pyrido[3,4-b]indole 
• 324518-45-8 (3S)-1-(4-methoxyphenyl)-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid 
• 73-22-3 L-Tryptophan 
• 3380-73-2 1-(4-methoxyphenyl)-1,2,3,4-tetrahydro-1H-pyrido[3,4-b]indole 
• 942217-34-7 1-(4-methoxyphenyl)-9H-pyrido[3,4-b]indole-3-carboxylic acid 
• 61-54-1 tryptamine 
• 105-13-5 4-Methoxybenzyl alcohol 
• 93879-05-1 tryptamine 

Relevant academic research and scientific papers

A convenient synthesis of β-carbolines by iron-catalyzed aerobic decarboxylative/dehydrogenative aromatization of tetrahydro-β-carbolines under air

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.

Visible light mediated selective oxidation of alcohols and oxidative dehydrogenation of N-heterocycles using scalable and reusable La-doped NiWO4nanoparticles

Visible light-mediated selective and efficient oxidation of various primary/secondary benzyl alcohols to aldehydes/ketones and oxidative dehydrogenation (ODH) of partially saturated heterocycles using a scalable and reusable heterogeneous photoredox catalyst in aqueous medium are described. A systematic study led to a selective synthesis of aldehydes under an argon atmosphere while the ODH of partially saturated heterocycles under an oxygen atmosphere resulted in very good to excellent yields. The methodology is atom economical and exhibits excellent tolerance towards various functional groups, and broad substrate scope. Furthermore, a one-pot procedure was developed for the sequential oxidation of benzyl alcohols and heteroaryl carbinols followed by the Pictet-Spengler cyclization and then aromatization to obtain the β-carbolines in high isolated yields. This methodology was found to be suitable for scale up and reusability. To the best of our knowledge, this is the first report on the oxidation of structurally diverse aryl carbinols and ODH of partially saturated N-heterocycles using a recyclable and heterogeneous photoredox catalyst under environmentally friendly conditions.

Selectivity-tunable oxidation of tetrahydro-β-carboline over an OMS-2 composite catalyst: preparation and catalytic performance

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.

Selective construction of alkaloid scaffolds by alcohol-based direct and mild aerobic oxidative Pictet-Spengler reactions

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.

Reusable, homogeneous water soluble photoredox catalyzed oxidative dehydrogenation of N-heterocycles in a biphasic system: Application to the synthesis of biologically active natural products

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.

Synthesis and biological evaluation of novel N9-heterobivalent β-carbolines as angiogenesis inhibitors

A series of novel N9-heterobivalent β-carbolines has been synthesized. All the novel compounds were tested for their anticancer activity against six tumour cell lines in vitro. Among these molecules, compounds 5b, and 5w exhibited strong cytotoxic activities with IC50 value of lower than 20 μM. Acute toxicities and antitumor efficacies of the selected compounds in mice were also evaluated, compounds 5b and 5w exhibited that tumour inhibition rate of over 40% in the Sarcoma 180 and Lewis lung cancer animal models. Preliminary structure–activity relationships (SARs) analysis indicated that: (1) C1-methylation and C7-methoxylation were favorable for increased activities; (2) 3-Pyridyl or 2-thienyl group substituent into position-1 of the β-carboline core, and the aryl substituent into another β-carboline ring might be detrimental to cytotoxic effects of this class compounds. Investigation of the preliminary mechanism of action demonstrated that compound 5b had obvious angiogenesis inhibitory effects in the chicken chorioallantoic membrane (CAM) assay.

Metal free one pot synthesis of Β-carbolines via a domino Pictet-Spengler reaction and aromatization

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).

Organic base-promoted efficient dehydrogenative/decarboxylative aromatization of tetrahydro-β-carbolines into β-carbolines under air

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.

Synthesis and structure-activity relationships of asymmetric dimeric β-carboline derivatives as potential antitumor agents

A series of newly asymmetric dimeric β-carbolines with a spacer of 4–6 methylene units between the indole nitrogen and the harmine oxygen were synthesized. Structures of all the novel synthesized compounds were confirmed by their spectral and analytical studies. All of the synthesized compounds were screened for their in vitro cytotoxic activity against nine cancer cell lines. The results revealed that compounds 7c, 7o and 7s exhibited the highest cytotoxic activities with IC50 values of less than 20 μM against the tumor cell lines tested. Acute toxicities and antitumor efficacies of the selected compounds in mice were also evaluated, and compound 7o exhibited potent antitumor activities with the tumor inhibition rate of over 40%. The wound healing assay displayed a specific impairment in the motility of the HT-29 cells, which suggested the anti-metastatic potential of compound 7o. Moreover, compound 7o had obvious angiogenesis inhibitory effects in the chicken chorioallantoic membrane (CAM) assay. Preliminary structure-activity relationship (SAR) analysis indicated that: (1) 3-phenylpropyl substituent at the N9-position of the indole ring was the most suitable group giving rise to potent cytotoxic agents; (2) the spacer length affected the antitumor potencies, and four methylene units were more favorable.

Dehydrogenation of N-Heterocycles by Superoxide Ion Generated through Single-Electron Transfer

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.