5-Aminopyrazole as precursor in design and synthesis of fused pyrazoloazines

• Ranjana Aggarwal and
• Suresh Kumar

Beilstein J. Org. Chem. 2018, 14, 203–242, doi:10.3762/bjoc.14.15

• in situ intramolecular cyclization of 5-aminopyrazole-4-caroxylate 35 with β-haloaldehydes 36 via the corresponding imine derivative was carried out in presence of Pd(PPh3)2Cl2 (1.0 mol %), Cu2O (1.0 mol %), 1,10-phenanthroline (2.0 mol %), TBAI (6 mol %), by Batra et al. [50] to generate the

Progress in copper-catalyzed trifluoromethylation

• Guan-bao Li,
• Chao Zhang,
• Chun Song and
• Yu-dao Ma

Beilstein J. Org. Chem. 2018, 14, 155–181, doi:10.3762/bjoc.14.11

• diamine ligands such as 1,10-phenanthroline (phen) were discovered. These diamines were able to accelerate the second step to regenerate sufficient amounts of reusable complexes A utilizing copper(I)-diamine complexes (Scheme 1), thus accelerating the trifluoromethylation of aryl/heteroaryl iodides

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation and chlorination. Part 2: Use of CF₃SO₂Cl

• Hélène Chachignon,
• Hélène Guyon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2800–2818, doi:10.3762/bjoc.13.273

• tandem trifluoromethylation/cyclisation processes. Dolbier and co-workers first proposed the use of N-arylacrylamides 3 to access trifluoromethylated 3,3-disubstituted 2-oxindoles 4 under photocatalytic conditions (Scheme 4) [11]. In the presence of Ru(phen)3Cl2 (phen = phenanthroline), a variety of N

• (PPh3)2 with Ru(phen)3Cl2 (phen: phenanthroline) at room temperature and adding a base, a variety of alkenes furnished the corresponding chlorotrifluoromethylated products under much milder conditions and with higher yields (Scheme 17). Moreover, tuning of the reaction conditions allowed to broaden the

• -deficient alkenes [26]. Such compounds could nonetheless be converted into the corresponding chlorotrifluoromethylated products by replacing the Ru(II) catalyst by Cu(dap)2Cl (dap = 2,9-bis(p-anisyl)-1,10-phenanthroline) (Scheme 18). This change of reactivity can supposedly be attributed to the high

Comparative profiling of well-defined copper reagents and precursors for the trifluoromethylation of aryl iodides

• Peter T. Kaplan,
• Jessica A. Lloyd,
• Mason T. Chin and
• David A. Vicic

Beilstein J. Org. Chem. 2017, 13, 2297–2303, doi:10.3762/bjoc.13.225

• [10][11]. [(SIMes)CuCF3] (1, SIMes = 1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene), which is in equilibrium with [(SIMes)2Cu][Cu(CF3)2] (2), can either be used directly or prepared in situ through the reaction of [(SIMes)Cu(O-t-Bu)] (3) with Me3SiCF3 (Scheme 2) [10]. Phenanthroline

• complexes of copper B1 were reported shortly after the NHC counterparts [5][12] and have reached much success in chemical synthesis due to the ease of preparation and the low cost of the phenanthroline ancillary ligand. [(phen)CuCF3] can now be purchased commercially, or prepared in situ by a variety of

• well-defined [LCuCF3] complex was employed directly or generated in situ by published reports. If so, it will be informative to know the extent of differences in reagent performance over time. Results and Discussion Because the phenanthroline-based system described as B1 (Scheme 1) is the most widely

Preparation of imidazo[1,2-a]-N-heterocyclic derivatives with gem-difluorinated side chains

• Layal Hariss,
• Kamal Bou Hadir,
• Mirvat El-Masri,
• Thierry Roisnel,
• René Grée and
• Ali Hachem

Beilstein J. Org. Chem. 2017, 13, 2115–2121, doi:10.3762/bjoc.13.208

• I2 under an O2 atmosphere [29]. However, only a poor yield was obtained (20%, Scheme 3). Then, we found that Cu(OAc)2·H2O (10 mol %) and 1,10-phenanthroline (10 mol %) in chlorobenzene at 160 °C under an O2 atmosphere, following the conditions recently reported by Hajra et al. [25], gave 7a in 62

• -aminopyridine (20 mg, 0.21 mmol, 1.2 equiv), enone 6a (51 mg, 0.17 mmol, 1 equiv), Cu(OAc)2·H2O (3.6 mg, 0.02 mmol, 10 mol %), and 1,10-phenanthroline (2.5 μL, 0.02 mmol, 10 mol %) in chlorobenzene (1 mL) was stirred in a reaction tube at 160 °C under an O2 atmosphere. After 25 h, 19F NMR monitoring indicated

• [1,2-a]pyridin-3-yl)(phenyl)methanone (7a) A mixture of 2-aminopyridine (25 mg, 0.26 mmol, 2.5 equiv), alcohol 5a (30 mg, 0.10 mmol, 1 equiv), DBU (0.03 mL, 0.20 mmol, 2 equiv), Cu(OAc)2·H2O (2.1 mg, 0.01 mmol, 10 mol %), and 1,10-phenanthroline (1.4 μL, 0.01 mmol, 10 mol %) in chlorobenzene (1 mL) was

Oxidative dehydrogenation of C–C and C–N bonds: A convenient approach to access diverse (dihydro)heteroaromatic compounds

• Santanu Hati,
• Ulrike Holzgrabe and
• Subhabrata Sen

Beilstein J. Org. Chem. 2017, 13, 1670–1692, doi:10.3762/bjoc.13.162

• -based catalysts are reported, that facilitates oxidative dehydrogenation of amines [72][73][74][75][76][77][78][79][80]. An exquisite example in this aspect involved phenanthroline-based catalysts that are applied for oxidative dehydrogenation of 2°-amines [81]. In this regard, Stahl and co-workers

• showed that coordination of 1,10-phenanthroline-5,6-dione (phd) with Zn2+ salts enhances the catalytic capacity of phd towards oxidative dehydrogenation of a variety of nitrogen heterocycles (Scheme 17). Thorough investigation and isolation of Zn-phd complexes revealed that the coordination of Zn2+ with

• MnO2. Selenium dioxide and potassium dichromate-mediated oxidative dehydrogenation of tetrahydro-β-carbolines [65][66]. Synthesis of substituted benzazoles in the presence of barium permanganate. Oxidative dehydrogenation with phenanthroline-based catalysts. PPTS = pyridinium p-toluenesulfonic acid

Nucleophilic and electrophilic cyclization of N-alkyne-substituted pyrrole derivatives: Synthesis of pyrrolopyrazinone, pyrrolotriazinone, and pyrrolooxazinone moieties

• Işıl Yenice,
• Sinan Basceken and
• Metin Balci

Beilstein J. Org. Chem. 2017, 13, 825–834, doi:10.3762/bjoc.13.83

• N-alkyne-substituted pyrrole derivatives 7a–d. A practical method is the coupling reaction of substituted pyrroles with alkynyl bromides using catalytic CuSO4·5H2O and 1,10-phenanthroline [31]. When alkynylation with 11a was carried out at 85 °C, the conversion was only 12%. We assume this is due to

• anhydrous toluene (20 mL), methyl 1H-pyrrole-2-carboxylate (9, 1.0 equiv), K3PO4 (2 equiv), CuSO4·5H2O (0.1 equiv) and 1,10-phenanthroline monohydrate (0.2 equiv) were added under N2 atmosphere. The reaction mixture was heated to 85 °C and stirred for 48 h. Then, the reaction mixture was cooled to room

• ) in freshly distilled anhydrous toluene (20 mL), methyl 1H-pyrrole-2-carboxylate (9, 0.57 g, 4.56 mmol), K3PO4 (1.94 g, 9.12 mmol), CuSO4·5H2O (0.11 g, 0.46 mmol) and 1,10-phenanthroline monohydrate (0.18 g, 0.91 mmol) were added and the resulting mixture was reacted as described above to obtain 7c

Transition-metal-catalyzed synthesis of phenols and aryl thiols

• Yajun Liu,
• Shasha Liu and
• Yan Xiao

Beilstein J. Org. Chem. 2017, 13, 589–611, doi:10.3762/bjoc.13.58

• -3-oxobutanamide (yield 65%), tetramethylethylenediamine (TMEDA, yield 84%), phenanthroline (yield 75%), 2,2,6,6-tetramethyl-3,5-heptanedione (TMHD, yield 95%) and dibenzoylmethane (L4, yield 97%) [27][28]. The reaction system afforded phenols from aryl halides and aryl bromides bearing electron

• catalyzed thiolation of aryl halides have been extensively studied. In 2006, the Sawada group reported that aryl iodides could couple with thiobenzoic acid in the presence of a copper catalyst and 1,10-phenanthroline (L17), affording S-aryl thiocarboxylates in excellent yields [102]. The coupled product was

Bi- and trinuclear copper(I) complexes of 1,2,3-triazole-tethered NHC ligands: synthesis, structure, and catalytic properties

• Shaojin Gu,
• Jiehao Du,
• Jingjing Huang,
• Huan Xia,
• Ling Yang,
• Weilin Xu and
• Chunxin Lu

Beilstein J. Org. Chem. 2016, 12, 863–873, doi:10.3762/bjoc.12.85

• [1][2][3][4][5][6][7][8][9][10][11][12]. A number of transition metal complexes of NHCs containing pyridine [13], pyrimidine [14], pyrazole [15][16], naphthyridine [17], pyridazine [18], and phenanthroline [19][20] donating groups have been studied in metal-catalyzed organic transformations. Recently

Recent advances in metathesis-derived polymers containing transition metals in the side chain

• Ileana Dragutan,
• Valerian Dragutan,
• Bogdan C. Simionescu,
• Albert Demonceau and
• Helmut Fischer

Beilstein J. Org. Chem. 2015, 11, 2747–2762, doi:10.3762/bjoc.11.296

• norbornene-substituted phenanthroline, that were polymerized by ROMP (Grubbs 3rd generation catalyst) to yield copolymers with valuable photo- and electroluminescent properties [65]. This kind of hybrid structure may induce high performance in LED devices. Early transition metal-containing polymers In

Carbon–carbon bond cleavage for Cu-mediated aromatic trifluoromethylations and pentafluoroethylations

• Tsuyuka Sugiishi,
• Hideki Amii,
• Kohsuke Aikawa and
• Koichi Mikami

Beilstein J. Org. Chem. 2015, 11, 2661–2670, doi:10.3762/bjoc.11.286

• trifluoroacetate and copper iodide. Preparation of trifluoromethylcopper from trifluoromethyl ketone. Trifluoromethylation of aryl iodides. aIsolated yield. b1 equivalent each of CF3Cu reagent and 1,10-phenanthroline were used. cReaction temperature was 50 °C. Pentafluoroethylation of aryl bromides. aYield was

Synthesis of bi- and bis-1,2,3-triazoles by copper-catalyzed Huisgen cycloaddition: A family of valuable products by click chemistry

• Zhan-Jiang Zheng,
• Ding Wang,
• Zheng Xu and
• Li-Wen Xu

Beilstein J. Org. Chem. 2015, 11, 2557–2576, doi:10.3762/bjoc.11.276

• olefins. Very recently, Ulven and co-workers reported the synthesis of triazole-linked phenanthroline ligands. They were obtained by the following steps: (1) 1,10-phenanthroline-2,9-dicarbaldehyde (56) was treated with the Ohira–Bestmann reagent to provide the corresponding dialkyne 57; (2) Dialkyne 57

• bistriazoles. The pyrene-appended thiacalix[4]arene-based bistriazole. The synthesis of triazole-based tetradentate ligands. The synthesis of phenanthroline-2,9-bistriazoles. The three-component reaction for the synthesis of bistriazoles. The one-pot synthesis of bistriazoles. The synthesis of polymer-bearing

Recent developments in copper-catalyzed radical alkylations of electron-rich π-systems

• Kirk W. Shimkin and
• Donald A. Watson

Beilstein J. Org. Chem. 2015, 11, 2278–2288, doi:10.3762/bjoc.11.248

• benzyl radicals under copper catalysis, an alkenylation similar to that developed by Nishikata was realized. Using a mixture of copper and 1,10-phenanthroline, benzylic halides were directly alkenylated using styrenes as coupling partners. Under these conditions, various allylbenzene derivatives were

• synthesized in very good yields (Scheme 16). Interestingly, the CuCl/phenanthroline catalyst system was also capable of cross coupling styrenes with α-bromocarbonyls and α-bromonitriles. EPR studies confirmed the presence of radical intermediates. Additions to alkynes Recently, ATR type catalysts have also

Beyond catalyst deactivation: cross-metathesis involving olefins containing N-heteroaromatics

• Kevin Lafaye,
• Cyril Bosset,
• Lionel Nicolas,
• Amandine Guérinot and
• Janine Cossy

Beilstein J. Org. Chem. 2015, 11, 2223–2241, doi:10.3762/bjoc.11.241

• with allylic alcohol delivered 88 in a low 31% yield and when an alkene containing a phenanthroline was used, no reaction occurred. By the light of the previously reported observations, these results could be imputed to the deactivation of the ruthenium catalyst caused by N-heteroaromatics (Scheme 33

• possessing a quinoxaline or a phenanthroline. CM between an acrylate and a 2-methoxy-5-bromo pyridine. Successful CM of an alkene containing a 2-chloropyridine. Variation of the substituent on the pyridine ring. CM involving alkenes containing a variety of N-heteroaromatics. Decomposition of methylidene 2 in

Recent advances in copper-catalyzed C–H bond amidation

• Jie-Ping Wan and
• Yanfeng Jing

Beilstein J. Org. Chem. 2015, 11, 2209–2222, doi:10.3762/bjoc.11.240

• or secondary sulfonamides 15 with the assistance of 1,10-phenanthroline as a ligand (Scheme 3). Notably, the asymmetric version of a similar amidation had been previously achieved by Clark et al. via copper catalysis in the presence of a chiral oxazoline ligand, which allowed the synthesis of

C–H bond halogenation catalyzed or mediated by copper: an overview

• Wenyan Hao and
• Yunyun Liu

Beilstein J. Org. Chem. 2015, 11, 2132–2144, doi:10.3762/bjoc.11.230

• ). The catalytic iodination of electron deficient 1,3-azoles was recently realized by Zhao et al. Under the catalytic conditions consisting of LiOt-Bu, 1,10-phenanthroline and CuBr2, a class of different conventional azoles 17, including benzoxazoles, benzothiazole, N-methylbenzimidazole, 5-phenyloxazole

Copper-catalyzed aerobic radical C–C bond cleavage of N–H ketimines

• Ya Lin Tnay,
• Gim Yean Ang and
• Shunsuke Chiba

Beilstein J. Org. Chem. 2015, 11, 1933–1943, doi:10.3762/bjoc.11.209

• additive 1,10-phenanthroline to 40 mol % slightly improved the yield, giving 3a in 40% yield (Table 1, entry 1). The use of 2,2’-bipyridine (bpy) provided a comparable result (Table 1, entry 2), while performing the reaction in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) led to lower yields of

• spirodienone 3a (Table 1, entry 3). We therefore decided to proceed with 1,10-phenanthroline as the optimal ligand and subsequently tested different Cu(II) and Cu(I) salts (Table 1, entries 4–7). The best results were obtained using 40 mol % CuI which provided 3a in 46% isolated yield (Table 1, entry 7). A

Synthesis and structures of ruthenium–NHC complexes and their catalysis in hydrogen transfer reaction

• Chao Chen,
• Chunxin Lu,
• Qing Zheng,
• Shengliang Ni,
• Min Zhang and
• Wanzhi Chen

Beilstein J. Org. Chem. 2015, 11, 1786–1795, doi:10.3762/bjoc.11.194

• displaying the typical octahedral geometry. The reaction of [RuL1(CH3CN)4](PF6)2 with triphenylphosphine and 1,10-phenanthroline resulted in the substitution of one and two coordinated acetonitrile ligands and afforded [RuL1(PPh3)(CH3CN)3](PF6)2 (4) and [RuL1(phen)(CH3CN)2](PF6)2 (5), respectively. The

• complexes show good catalytic activity in the transfer hydrogenation of ketones. The reaction of acetonitrile-coordinated Ru–NHC complex 2 with other donors such as triphenylphosphine and 1,10-phenanthroline was also studied. Results and Discussion Synthesis and characterization of [Ru(L1)2(CH3CN)2](PF6)2

• triphenylphosphine and 1,10-phenanthroline The coordinated acetonitrile ligands could be easily replaced by various N- and P-donors [22]. The reactions of the acetonitrile-coordinated Ru–NHC complexes with other ligands were studied. The reaction of complex 2 with an excess of triphenylphosphine and 1,10

Pyridinoacridine alkaloids of marine origin: NMR and MS spectral data, synthesis, biosynthesis and biological activity

• Louis P. Sandjo,
• Victor Kuete and
• Maique W. Biavatti

Beilstein J. Org. Chem. 2015, 11, 1667–1699, doi:10.3762/bjoc.11.183

• 70% overall yield. The synthesis started with 4-bromo-1,10-phenanthroline subjected to an oxidative cleavage with potassium permanganate to afford binicotinic acid. The binicotinic acid product was esterified using dicyclohexylcarbodiimide (DCC) in methanol and the resulting ester was cross-coupled

• ) has been performed by Lotter and Bracher [67]. The route included four steps, but unfortunately, the overall yield was only 7%. Like in method A, the synthesis started with 1,10-phenanthroline to prepare binicotinic acid via oxidative cleavage by potassium permanganate. The esterification took place

• decarboxylated to give kynuramine (65). The latter, by reaction with dopamine, forms the benzo-3,6-phenanthroline intermediate 68, which in turn gave shermilamine B (67) upon reaction with cysteine (Figure 8) [76]. The compounds 13-didemethylaminocycloshermilamine D (31) and demethyldeoxyamphimedine (9) (Figure

Self-assembly of heteroleptic dinuclear metallosupramolecular kites from multivalent ligands via social self-sorting

• Christian Benkhäuser and
• Arne Lützen

Beilstein J. Org. Chem. 2015, 11, 693–700, doi:10.3762/bjoc.11.79

• Christian Benkhauser Arne Lutzen Kekulé-Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Str. 1, D-53121 Bonn, Germany 10.3762/bjoc.11.79 Abstract A Tröger's base-derived racemic bis(1,10-phenanthroline) ligand (rac)-1 and a bis(2,2'-bipyridine) ligand with a

• without putting a considerable amount of steric strain into the aggregate. In the search for ligand structures that fulfill these requirements we came up with ligands 1 and 2 that are depicted in Figure 1. Ligand 1 has a very rigid twisted V-shaped structure that presents its phenanthroline units in a way

• . Scheme 5 summarizes the coordination behavior of the two ligands 1 and 2 and their mixture towards copper(I) ions. Conclusion In summary, we have synthesized two concave or V-shaped multivalent ligands − a dissymmetric bis(phenanthroline) ligand (rac)-1 based on the Tröger's base scaffold in its racemic

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

• Igor B. Krylov,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2015, 11, 92–146, doi:10.3762/bjoc.11.13

Copper-promoted hydration and annulation of 2-fluorophenylacetylene derivatives: from alkynes to benzo[b]furans and benzo[b]thiophenes

• Yibiao Li,
• Liang Cheng,
• Xiaohang Liu,
• Bin Li and
• Ning Sun

Beilstein J. Org. Chem. 2014, 10, 2886–2891, doi:10.3762/bjoc.10.305

• product (Table 1, entry 1). The usage of CuCl and 1,10-phenanthroline (1,10-phen) as a ligand in CH3CN at 80 °C showed that 2a could be isolated in 35% yield (Table 1, entry 2). The screening of the various solvents revealed that the solvent played an important role in this hydration and annulation

An integrated photocatalytic/enzymatic system for the reduction of CO₂ to methanol in bioglycerol–water

• Michele Aresta,
• Angela Dibenedetto,
• Tomasz Baran,
• Antonella Angelini,
• Przemysław Łabuz and
• Wojciech Macyk

Beilstein J. Org. Chem. 2014, 10, 2556–2565, doi:10.3762/bjoc.10.267

• phenanthroline did not improve the yield to appreciable extent, thus the Rh-complex was used. Other photomaterials which are active upon visible light irradiation were also tested, such as Fe/ZnS, Co/ZnS, Ag/ZnS, ZnBiO4, AgVO4, NiO, CrF3@TiO2, tiron@TiO2. However, they did not show significant activity in the

• green precipitate was obtained, isolated and analyzed, resulting in the title compound. Synthesis of [Cp*Rh(bpy)H2O]Cl2 [Cp*Rh(bpy)H2O]Cl2 was obtained from [Cp*RhCl2]2 as reported in [29]. Phenanthroline was used instead of bpy to generate [Cp*Rh(phen)(H2O)]Cl2. The analogous Ir complex was prepared

Preparation of phosphines through C–P bond formation

• Iris Wauters,
• Wouter Debrouwer and
• Christian V. Stevens

Beilstein J. Org. Chem. 2014, 10, 1064–1096, doi:10.3762/bjoc.10.106

Towards allosteric receptors – synthesis of β-cyclodextrin-functionalised 2,2’-bipyridines and their metal complexes

• Christopher Kremer,
• Gregor Schnakenburg and
• Arne Lützen

Beilstein J. Org. Chem. 2014, 10, 814–824, doi:10.3762/bjoc.10.77

• ][32][33][34][35]. Thus, we chose to prepare 2,9-bis[2,6-dimethoxyphenyl]-1,10-phenanthroline (22) as such a sterically congested ligand (Scheme 6) [36]. 22 was synthesised starting from 1,10-phenanthroline via N,N'-dialkylation to dibromide 23 in very good yield [37]. Oxidation of 23 with potassium

• )]PF6, and [Zn(22)(1)](OTf)2 as evidenced by MALDI mass spectrometry and NMR spectroscopy (Figure 6 and Figure 7). Hence, zinc(II) ions or their complexes with a single, sterically demanding phenanthroline ligand like 22 as well as a similar [Cu(22)]+ complex were all found to be good effectors for

• metal-to-ligand-to-substrate assemblies. Zinc(II) or copper(I) phenanthroline complexes with sterically very demanding phenanthrolines were found to be effective to achieve a 1:1 effector–receptor stoichiometry. This makes these ligands promising candidates that could act as potential allosteric