Selective copper(II) acetate and potassium iodide catalyzed oxidation of aminals to dihydroquinazoline and quinazolinone alkaloids

• Matthew T. Richers,
• Chenfei Zhao and
• Daniel Seidel

Beilstein J. Org. Chem. 2013, 9, 1194–1201, doi:10.3762/bjoc.9.135

• Matthew T. Richers Chenfei Zhao Daniel Seidel Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA 10.3762/bjoc.9.135 Abstract Copper(II) acetate/acetic acid/O2 and potassium iodide/tert-butylhydroperoxide systems are shown

• were also explored. The use of Cu(OAc)2 and methanol, while appropriate for furnishing deoxyvasicine (2) from aminal 7, did not result in satisfactory yields of deoxyvasicinone (4, Table 1). Attempts to use other copper(I) or copper(II) salts and solvents under oxygen without the addition of acid to

• acetic acid in addition to oxygen and catalytic copper(II) salts was determined to prevent overoxidation of dihydroquinazolines, allowing access to these structures under mild conditions. A number of natural products and their analogues were obtainable by these methods, which should facilitate the

Methylidynetrisphosphonates: Promising C₁ building block for the design of phosphate mimetics

• Vadim D. Romanenko and
• Valery P. Kukhar

Beilstein J. Org. Chem. 2013, 9, 991–1001, doi:10.3762/bjoc.9.114

• diazomethylenebisphosphonate and diethyl phosphite in the presence of copper(II) bis(acetylacetonate) provides trisphosphonate ester 6 (Scheme 13). The yield is poor (20%) but the product can be isolated in the pure state and the method is presumably general (cf. [37]). The starting tetraalkyl diazomethylenebisphosphonates

Superstructures of fluorescent cyclodextrin via click-reaction

• Arkadius Maciollek,
• Helmut Ritter and
• Rainer Beckert

Beilstein J. Org. Chem. 2013, 9, 827–831, doi:10.3762/bjoc.9.94

• µmol) sodium ascorbate and 18 mg (73.5 µmol) copper(II) sulfate pentahydrate were suspended in 5 mL dimethylformamide in a pressure-resistant microwave test tube provided with a magnetic stirring bar. The tube was sealed and placed in the microwave and irradiated at 140 °C and 100 W for 30 min. The

Intramolecular carbolithiation of N-allyl-ynamides: an efficient entry to 1,4-dihydropyridines and pyridines – application to a formal synthesis of sarizotan

• Wafa Gati,
• Mohamed M. Rammah,
• Mohamed B. Rammah and
• Gwilherm Evano

Beilstein J. Org. Chem. 2012, 8, 2214–2222, doi:10.3762/bjoc.8.250

• nucleophiles. By using a slightly modified Hsung’s procedure, a series of N-allyl-ynamides 1 could be readily prepared in acceptable yields using a combination of copper(II) sulfate pentahydrate (40 mol %) and 1,10-phenanthroline (80 mol %) with potassium phosphate in refluxing toluene, the major side reaction

Palladium-catalyzed dual C–H or N–H functionalization of unfunctionalized indole derivatives with alkenes and arenes

• Gianluigi Broggini,
• Egle M. Beccalli,
• Andrea Fasana and
• Silvia Gazzola

Beilstein J. Org. Chem. 2012, 8, 1730–1746, doi:10.3762/bjoc.8.198

• cyclization of alkenylindoles by Pd(II) catalysis under carbonylative conditions [81][82]. This approach, based on the use of copper(II) chloride as oxidant, has been applied to 2- and 3-alkenylindoles, resulting in a domino process that involves an alkenylation/carboxylation sequence (Scheme 23). Thus

• requires an oxidation by the copper(II) salt to the Pd(II) species, which is then suitable to restart a new catalytic cycle. Recently, the oxidative Pd(II)-catalyzed strategy for the cyclization of alkenylindoles has been extended to the intramolecular domino reactions of indolylallylamides by using the

Parallel solid-phase synthesis of diaryltriazoles

• Matthias Wrobel,
• Jeffrey Aubé and
• Burkhard König

Beilstein J. Org. Chem. 2012, 8, 1027–1036, doi:10.3762/bjoc.8.115

• example of a more complex alkyne. The azide–alkyne [3 + 2] cycloaddition was catalyzed with copper(II) sulfate pentahydrate and L-ascorbic acid in DMF overnight at room temperature. A solution of EDTA was added to remove the remaining copper cations from the resin. Resin cleavage under acidic conditions

• L-ascorbic acid (0.5 equiv) as reducing agent and copper(II) sulfate pentahydrate (10 mol %). After the terminal alkyne (4 equiv) was added, the reaction mixture was stirred for 22 h at room temperature. The resin was washed with dimethylformamide, methanol and dichloromethane (each solvent 2 mL/100

Regioselective chlorination and bromination of unprotected anilines under mild conditions using copper halides in ionic liquids

• Han Wang,
• Kun Wen,
• Nurbiya Nurahmat,
• Yan Shao,
• He Zhang,
• Chao Wei,
• Ya Li,
• Yongjia Shen and
• Zhihua Sun

Beilstein J. Org. Chem. 2012, 8, 744–748, doi:10.3762/bjoc.8.84

• reported several decades ago with chloride salts of several transition metals [5]. Copper(II) chloride (1) was found to be one of the best reagents for this transformation, which yielded mostly the para-chlorinated product with minor ortho- and dichlorinated products. The mechanism was believed to be

Facile synthesis of nitrophenyl 2-acetamido-2-deoxy-α-D-mannopyranosides from ManNAc-oxazoline

• Karel Křenek,
• Petr Šimon,
• Lenka Weignerová,
• Barbora Fliedrová,
• Marek Kuzma and
• Vladimír Křen

Beilstein J. Org. Chem. 2012, 8, 428–432, doi:10.3762/bjoc.8.48

• ] affording oxazoline 3 in 75% yield. The glycosylation of phenol and p-nitrophenol with oxazoline 3 was extensively tested. We tested a large array of reaction conditions, including variation of catalyst (copper(II) chloride [12][15], 2,2-diphenyl-1-picrylhydrazyl, zinc chloride, tin(IV) chloride) and

A ferrocene redox-active triazolium macrocycle that binds and senses chloride

• Nicholas G. White and
• Paul D. Beer

Beilstein J. Org. Chem. 2012, 8, 246–252, doi:10.3762/bjoc.8.25

• , C≡CH), 1.87 (m, 4H, trz-CH2-CH2); 13C NMR (CDCl3) δ 147.3, 120.6, 83.9, 82.7, 69.9, 69.6, 69.0, 49.5, 28.1, 24.6, 18.0; HRMS–ESI (m/z): [M + Na]+ calcd for C26H28N6Fe·Na, 503.1617; found, 503.1614. Bis(triazole) macrocycle 3 The bis(alkyne) 2 (0.120 g, 0.250 mmol) and copper(II) acetate monohydrate

Highly efficient cyclosarin degradation mediated by a β-cyclodextrin derivative containing an oxime-derived substituent

• Michael Zengerle,
• Florian Brandhuber,
• Christian Schneider,
• Franz Worek,
• Georg Reiter and
• Stefan Kubik

Beilstein J. Org. Chem. 2011, 7, 1543–1554, doi:10.3762/bjoc.7.182

• ][41]. The alkyne 6 required for the synthesis of 2a was obtained from propargyl bromide and 3-formylpyridine oxime (Scheme 6), and those for 2b, 2c, and 2d, following the routes shown in Scheme 7. Reaction of these alkynes with 4 in the presence of copper(II) sulfate, sodium ascorbate and tris[(1

Synthesis and oxidation of some azole-containing thioethers

• Andrei S. Potapov,
• Nina P. Chernova,
• Vladimir D. Ogorodnikov,
• Tatiana V. Petrenko and
• Andrei I. Khlebnikov

Beilstein J. Org. Chem. 2011, 7, 1526–1532, doi:10.3762/bjoc.7.179

• dismutase-like activity of copper(II) complexes with bis(pyrazole) ligands [5][6]. Copper(II) complexes with azole-derived thioether ligands were proposed as models for type I copper proteins [7]. The sulfur atom in a thioether spacer gives an additional possibility for modification of the ligand structure

Development of the titanium–TADDOLate-catalyzed asymmetric fluorination of β-ketoesters

• Lukas Hintermann,
• Mauro Perseghini and
• Antonio Togni

Beilstein J. Org. Chem. 2011, 7, 1421–1435, doi:10.3762/bjoc.7.166

• malonic esters with elemental fluorine in the presence of hydrated copper(II) nitrate at the 10 mol % level [73]. Still, the generality and synthetic potential of Lewis acid catalyzed α-halogenations of carbonyl compounds were not established. Reactivity screening: Fluorination of β-ketoesters in the

Amines as key building blocks in Pd-assisted multicomponent processes

• Didier Bouyssi,
• Nuno Monteiro and
• Geneviève Balme

Beilstein J. Org. Chem. 2011, 7, 1387–1406, doi:10.3762/bjoc.7.163

• added to the reaction medium with concomitant addition of 10 mol % of Cu(OTf)2 necessary to complete the cyclization step. The proposed mechanism involves formation of an imine intermediate, which attacks the triple bond activated by the copper(II) complex. The resulting iminium was finally trapped by

Ugi post-condensation copper-triggered oxidative cascade towards pyrazoles

• Aurélie Dos Santos,
• Laurent El Kaim,
• Laurence Grimaud and
• Caroline Ronsseray

Beilstein J. Org. Chem. 2011, 7, 1310–1314, doi:10.3762/bjoc.7.153

• Pyrazolidinones were prepared in a two-step sequence starting from α-hydrazonocarboxylic acids. After a four-component Ugi coupling, the resulting hydrazone was engaged in a copper triggered [3 + 2] cycloaddition/aerobic oxidation cascade. Keywords: aerobic oxidation; copper(II); [3 + 2] cycloaddition; hydrazone

• , cyclocondensations and organometalic couplings, there was no existing description of radical processes on such adducts. Thus, we decided to undertake various studies using xanthate transfer [8][9][10], Mn(III) or copper(II) triggered oxidative couplings [11][12]. We recently reported a new synthesis of fused

• triggered either by copper acetate or acetic acid [24][25][26][27][28][29]. The resulting pyrazoline A may be oxidized by copper(II) salts forming intermediate D after addition of water [30][31]. Two alternative paths may then be observed from D: Ring-opening leading to azo or hydrazono derivatives such as

An overview of the key routes to the best selling 5-membered ring heterocyclic pharmaceuticals

• Marcus Baumann,
• Ian R. Baxendale,
• Steven V. Ley and
• Nikzad Nikbin

Beilstein J. Org. Chem. 2011, 7, 442–495, doi:10.3762/bjoc.7.57

• ]. For this reaction 2-amino-5-methylpyridine (228) was condensed with an aldehyde to form an intermediate imine to which is added a terminal alkyne in the presence of copper(I) chloride. A copper(II) triflate catalyst is then used to promote a Lewis acid promoted 5-exo-dig heteroannulation to furnish

Palladium- and copper-mediated N-aryl bond formation reactions for the synthesis of biological active compounds

• Carolin Fischer and
• Burkhard Koenig

Beilstein J. Org. Chem. 2011, 7, 59–74, doi:10.3762/bjoc.7.10

• Buchwald [6][7] and Hartwig [8][9] has been a major breakthrough in this field. More recently, Chan [10] and Lam [11][12] introduced the copper-mediated arylation of N-nucleophiles using stoichiometric copper(II) acetate and boronic acids. Collman improved the procedure using catalytic amounts of [Cu(OH

• , was achieved by reacting 9-N-purines 91 with an excess of arylboronic acid 92 in the presence of copper(II) acetate, molecular sieves and phenanthroline (Scheme 22). Bakkestuen and Gundersen showed that electron-donating and electron-withdrawing substituents on the arylboronic acid were tolerated

Calix[4]arene-click-cyclodextrin and supramolecular structures with watersoluble NIPAAM-copolymers bearing adamantyl units: “Rings on ring on chain”

• Bernd Garska,
• Monir Tabatabai and
• Helmut Ritter

Beilstein J. Org. Chem. 2010, 6, 784–788, doi:10.3762/bjoc.6.83

• pump vacuum. N-Isopropylacrylamide (NIPAAM) 97%, sodium azide (99.5%) and azobisisobutyronitrile (98%) were purchased from Aldrich Chemicals (Germany) and used as received. Copper-(II)-sulfate pentahydrate (99%) was obtained from Carl Roth GmbH & CO., and sodium L(+)-ascorbate (99%) obtained from

Pd-catalyzed decarboxylative Heck vinylation of 2-nitrobenzoates in the presence of CuF₂

• Lukas J. Gooßen,
• Bettina Zimmermann and
• Thomas Knauber

Beilstein J. Org. Chem. 2010, 6, No. 43, doi:10.3762/bjoc.6.43

• , in which p-benzoquinone is employed as oxidant [24]. However, their protocol is strictly limited to highly activated benzoates. We herein disclose an alternative protocol for the Pd-catalyzed decarboxylative Heck reaction, in which copper(II) fluoride is utilized as the oxidant. This way, various

• Nilsson and Cohen in protodecarboxylation reactions [34][35][36][37]. Thus, we investigated several copper bases in place of silver carbonate. With copper(I) oxide and copper(II) carbonate, nitrobenzene (4a) was formed predominantly, while the desired Heck product was observed only in trace quantities

• (entries 9 and 10). When copper(II) fluoride was used, we obtained 27% of the product along with 48% of the undesired protodecarboxylation product (entry 11). Even after careful exclusion of moisture and the use of preformed potassium 2-nitrobenzoate, the yields remained unsatisfactory (41%) and the

Molecular recognition of organic ammonium ions in solution using synthetic receptors

• Andreas Späth and
• Burkhard König

Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32

Convergent syntheses of Le^X analogues

• An Wang,
• Jenifer Hendel and
• France-Isabelle Auzanneau

Beilstein J. Org. Chem. 2010, 6, No. 17, doi:10.3762/bjoc.6.17

• thioethyl glycoside 9 under copper (II) bromide–tetrabutylammonium bromide activation (Scheme 3). The desired Lex trisaccharide 29 was obtained in excellent yield and the α-configuration of the newly formed fucosidic bond was confirmed by 1H NMR (JH-1′,H-2′ = 3.7 Hz). The 6-chlorohexyl trisaccharide

Synthesis and Diels–Alder cycloaddition reaction of norbornadiene and benzonorbornadiene dimers

• Bilal Nişancı,
• Erdin Dalkılıç,
• Murat Güney and
• Arif Daştan

Beilstein J. Org. Chem. 2009, 5, No. 39, doi:10.3762/bjoc.5.39

• , 124.36, 124.18, 121.62, 121.58, 69.65, 55,77, 52.05, −9.70. Reaction of (1,4-dihydro-1,4-methano-naphthalen-2-yl)trimethylstannane (6) with Cu(NO3)2·3H2O: Copper(II) nitrate trihydrate (345 mg, 1.4 mmol) was added portionwise to a solution of 6 (435 mg, 1.4 mmol) in THF (6 mL) at room temperature. The

• MHz, CDCl3): δ 155.46, 154.28, 143.12, 143.07, 74.70, 55.77, 52.15, −9.90. Reaction of (bicyclo[2.2.1]hepta-2,5-dien-2-yl)trimethylstannane (15) with Cu(NO3)2·3H2O: Copper(II) nitrate trihydrate (1.13 g, 4.69 mmol) was added portionwise to a solution of 15 (1.2 g, 4.69 mmol) in THF (10 mL) at room

The use of silicon- based tethers for the Pauson- Khand reaction

• Adrian P. Dobbs,
• Ian J. Miller and
• Saša Martinović

Beilstein J. Org. Chem. 2007, 3, No. 21, doi:10.1186/1860-5397-3-21

• this new methodology from chlorodiisopropylsilane. The synthesis of allyldiisopropylsilane proceeded easily and with high yield. Next a variety of methods were attempted for the conversion of the silicon-hydrogen bond to a silicon-chloride bond: chlorine in carbon tetrachloride; copper (II) chloride

The first salen- type ligands derived from 3',5'-diamino- 3',5'-dideoxythymidine and -dideoxyxylothymidine and their corresponding copper(II) complexes

• Daniel Koth,
• Michael Gottschaldt,
• Helmar Görls and
• Karolin Pohle

Beilstein J. Org. Chem. 2006, 2, No. 17, doi:10.1186/1860-5397-2-17

• as xylo-configuration and the preparation of copper(II) complexes derived from their corresponding Schiff bases. Starting from thymidine, the amino derivatives were prepared in a three and four step reaction sequence respectively. The absolute configuration of the ligands was proved by the three-bond

• 1H-1H spin spin coupling constants 3J obtained by NMR-studies. Condensation of the amino derivatives with salicylic aldehydes resulted in the corresponding diimines, which represent a new class of chiral salen-type ligands. All ligands formed uncharged stable copper(II) complexes. The structure of 3

• ',5'-bis(3,5-di-tert-butylsalicylaldiminato)-3',5'-dideoxyxylothymidine-copper(II) could be determined by single crystal X-ray structure analysis. The copper centre in this complex has distorted tetrahedral coordination geometry. Conclusion For the synthesis of 3',5'-diamino-3',5'-dideoxy thymidines