4006-50-2Relevant academic research and scientific papers
TWO PHENAZINE DERIVATIVES, POLYCARTINE A AND B FROM IDESIA POLYCARPA MAXIM (FLACOURTIACEAE)
Moritake, Mikiko,Ueda, Katsuhiro,Mori, Iwao
, p. 1425 - 1426 (1987)
Two hydrogenated phenazines have been isolated from the fruits of Idesia polycarpa Maxim and their structures were determined by spectral and chemical means.
One-pot production of phenazine from lignin-derived catechol
He, Zhimin,Qi, Wei,Ren, Tianyu,Yan, Ning
, p. 1224 - 1230 (2022/02/17)
Upgrading lignin-derived monomeric products is crucial in bio-refineries to effectively utilize lignin. Herein, we report a simple strategy to convert catechol to phenazine, a useful N-heterocycle three-aromatic-ring compound, whose current synthetic procedure is complex via a petroleum-derived feedstock. The reaction uses catechol as the sole carbon source and aqueous ammonia as reaction media and a nitrogen source. Without additional solvents, phenazine was obtained in 67% yield in the form of high purity crystals (>97%) over a Pd/C catalyst after a one-pot-two-stage reaction. When cyclohexane was used as a co-solvent in the first step, a higher yield (81%) and purity (>99%) were achieved. Mechanistic investigations involving control experiments and an isotope labeling study reveal that hydrogenation, amination, coupling and dehydrogenation reactions are the key steps leading to phenazine formation. The conversion of other lignin-derived catechols highlights that the protocol is extendable to produce substituted phenazines.
Hydrogenation of N-Heteroarenes Using Rhodium Precatalysts: Reductive Elimination Leads to Formation of Multimetallic Clusters
Kim, Sangmin,Loose, Florian,Bezdek, Máté J.,Wang, Xiaoping,Chirik, Paul J.
, p. 17900 - 17908 (2019/11/19)
A rhodium-catalyzed method for the hydrogenation of N-heteroarenes is described. A diverse array of unsubstituted N-heteroarenes including pyridine, pyrrole, and pyrazine, traditionally challenging substrates for hydrogenation, were successfully hydrogenated using the organometallic precatalysts, [(η5-C5Me5)Rh(N-C)H] (N-C = 2-phenylpyridinyl (ppy) or benzo[h]quinolinyl (bq)). In addition, the hydrogenation of polyaromatic N-heteroarenes exhibited uncommon chemoselectivity. Studies into catalyst activation revealed that photochemical or thermal activation of [(η5-C5Me5)Rh(bq)H] induced C(sp2)-H reductive elimination and generated the bimetallic complex, [(η5-C5Me5)Rh(μ2,η2-bq)Rh(η5-C5Me5)H]. In the presence of H2, both of the [(η5-C5Me5)Rh(N-C)H] precursors and [(η5-C5Me5)Rh(μ2,η2-bq)Rh(η5-C5Me5)H] converted to a pentametallic rhodium hydride cluster, [(η5-C5Me5)4Rh5H7], the structure of which was established by NMR spectroscopy, X-ray diffraction, and neutron diffraction. Kinetic studies on pyridine hydrogenation were conducted with each of the isolated rhodium complexes to identify catalytically relevant species. The data are most consistent with hydrogenation catalysis prompted by an unobserved multimetallic cluster with formation of [(η5-C5Me5)4Rh5H7] serving as a deactivation pathway.
Acceptorless Dehydrogenative Coupling Using Ammonia: Direct Synthesis of N-Heteroaromatics from Diols Catalyzed by Ruthenium
Daw, Prosenjit,Ben-David, Yehoshoa,Milstein, David
supporting information, p. 11931 - 11934 (2018/09/27)
The synthesis of N-heteroaromatic compounds via an acceptorless dehydrogenative coupling process involving direct use of ammonia as the nitrogen source was explored. We report the synthesis of pyrazine derivatives from 1,2-diols and the synthesis of N-substituted pyrroles by a multicomponent dehydrogenative coupling of 1,4-diols and primary alcohols with ammonia. The acridine-based Ru-pincer complex 1 is an effective catalyst for these transformations, in which the acridine backbone is converted to an anionic dearomatized PNP-pincer ligand framework.
Chemo-Enzymatic Synthesis of Pyrazines and Pyrroles
Xu, Jin,Green, Anthony P.,Turner, Nicholas J.
supporting information, p. 16760 - 16763 (2018/11/27)
Herein we report the biocatalytic synthesis of substituted pyrazines and pyrroles using a transaminase (ATA) to mediate the key amination step of the ketone precursors. Treatment of α-diketones with ATA-113 in the presence of a suitable amine donor yielded the corresponding α-amino ketones which underwent oxidative dimerization to the pyrazines. Selective amination of α-diketones in the presence of β-keto esters afforded substituted pyrroles in a biocatalytic equivalent of the classical Knorr pyrrole synthesis. Finally we have shown that pyrroles can be prepared by internal amine transfer catalyzed by a transaminase in which no external amine donor is required.
Pd-Catalyzed, Ligand-Enabled Stereoselective 1,2-Iodine(III) Shift/1,1-Carboxyalkynylation of Alkynylbenziodoxoles
Wu, Junliang,Xu, Kai,Hirao, Hajime,Yoshikai, Naohiko
supporting information, p. 1521 - 1525 (2017/02/10)
A PdII-catalyzed 2:1 coupling reaction of alkynylbenziodoxole with carboxylic acid to afford (alk-1-en-3-ynyl)benziodoxole, which is efficiently promoted by an octahydrophenazine ligand, is reported. The reaction involves a Pd-assisted 1,2-iodine(III) shift of the alkynylbenziodoxole followed by stereoselective introduction of carboxy and alkynyl groups (the latter originating from another molecule of the alkynylbenziodoxole) into the 1-position of the transient Pd-vinylidene species. The product of this 1,1-carboxyalkynylation reaction serves as a new functionalized enyne-type building block for further synthetic transformations.
Ligustrazine-fused cyclic compound and medicine composition thereof, as well as application in medicine thereof
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Paragraph 0038; 0039; 0040; 0043; 0044, (2017/07/21)
The invention discloses a ligustrazine-fused cyclic compound and a medicine composition thereof and application in a medicine. The ligustrazine-fused cyclic compound has the following structural general formula I: as shown in the specification. The medicine composition is a medicinal active component for the ligustrazine-fused cyclic compound and a pharmaceutically acceptable carrier, an excipient, a diluent, an adjuvant, a medium or a combination thereof; the ligustrazine-fused cyclic compound and the medicine composition can be used for preventing or treating cardiovascular and cerebrovascular diseases, digestive system diseases, respiratory diseases, the alzheimer's disease, kidney diseases and complications of the above-mentioned diseases due to thrombus and excessive free radicals. The ligustrazine-fused cyclic compound disclosed by the invention has an extremely good inhibition effect on in vitro ADP (adenosine diphosphate)-induced platelet aggregation; meanwhile, compared with the pharmacokinetic property of ligustrazine serving as a female parent, the pharmacokinetic property of the ligustrazine-fused cyclic compound in the body of a rat is obviously improved.
Phosphine Supported Ruthenium Nanoparticle Catalyzed Synthesis of Substituted Pyrazines and Imidazoles from α-Diketones
Ganji, Prasad,Van Leeuwen, Piet W. N. M.
, p. 1768 - 1774 (2017/02/10)
A new methodology has been developed for the synthesis of highly substituted nitrogen heterocycles such as pyrazines and imidazoles starting from α-diketones using phosphine supported ruthenium nanoparticles (RuNPs) as catalysts. Ruthenium nanoparticles Ru1-Ru4 supported with different phosphines such as dbdocphos, dppp, DPEphos, and Xantphos are screened, of which Ru1 and Ru4 are found to be the most active. Interestingly, aryl-substituted and alkyl-substituted α-diketones produced different products: namely, pyrazine and imidazoles, respectively. This reaction methodology has been applied to the synthesis of a key intermediate (2m) of the marine cytotoxic natural product Dragmacidin B and an estrogen receptor (2l). This work represents the first examples of pyrazines prepared by RuNPs.
The reaction of α-halocarbonyl compounds with (NH4)OH, (NH4)So4 or NH4CI solution under microwave-irradiation
Utsukihara, Takamitsu,Koshimura, Masahiro,Kitsuta, Kazunori,Sato, Akinori,Matsushita, Masatoshi,Takahashi, T. Tomoyoshi,Horiuchi, C. Akira
, p. 1495 - 1502 (2017/11/10)
Reaction of α-halo ketone (a-bromo ketone) under microwave, irradiation gives the pyrazine and quinoxaline derivative in good yields. This reaction affords a clean and convenient synthetic method for pyrazine and quinoxaline derivatives.
Direct amination of bio-alcohols using ammonia
Pingen, Dennis,Diebolt, Olivier,Vogt, Dieter
, p. 2905 - 2912 (2013/10/21)
A slightly adapted catalyst system has been successfully applied in the direct amination of primary and secondary alcohols. Moreover, the applicability to diols has been shown, giving high selectivity towards the primary diamines. It was found that the Ru/P ratio as well as the amount of ammonia used are highly important in this system, especially for higher substrate loadings. The catalyst was employed on a larger batch scale for the conversion of isomannide to the corresponding diamine. Additionally, it was shown that the catalyst is stable for at least six consecutive runs. No significant loss of activity and selectivity was observed.
