- Coupling of Reformatsky Reagents with Aryl Chlorides Enabled by Ylide-Functionalized Phosphine Ligands
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The coupling of aryl chlorides with Reformatsky reagents is a desirable strategy for the construction of α-aryl esters but has so far been substantially limited in the substrate scope due to many challenges posed by various possible side reactions. This limitation has now been overcome by the tailoring of ylide-functionalized phosphines to fit the requirements of Negishi couplings. Record-setting activities were achieved in palladium-catalyzed arylations of organozinc reagents with aryl electrophiles using a cyclohexyl-YPhos ligand bearing an ortho-tolyl-substituent in the backbone. This highly electron-rich, bulky ligand enables the use of aryl chlorides in room temperature couplings of Reformatsky reagents. The reaction scope covers diversely functionalized arylacetic and arylpropionic acid derivatives. Aryl bromides and chlorides can be converted selectively over triflate electrophiles, which permits consecutive coupling strategies.
- Hu, Zhiyong,Wei, Xiao-Jing,Handelmann, Jens,Seitz, Ann-Katrin,Rodstein, Ilja,Gessner, Viktoria H.,Goo?en, Lukas J.
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supporting information
p. 6778 - 6783
(2021/02/01)
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- Synthetic method of benzofuranone
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The invention provides a synthetic method of benzofuranone. According to the method, o-cresol which is relatively easy to obtain is used as an initial raw material, and the target product benzofuranone is prepared through four-step reaction; and the whole preparation process is mild in condition, high in yield, easy to operate, small in environmental pollution and suitable for large-scale industrial production.
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- Thermal Stability and Explosive Hazard Assessment of Diazo Compounds and Diazo Transfer Reagents
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Despite their wide use in academia as metal-carbene precursors, diazo compounds are often avoided in industry owing to concerns over their instability, exothermic decomposition, and potential explosive behavior. The stability of sulfonyl azides and other diazo transfer reagents is relatively well understood, but there is little reliable data available for diazo compounds. This work first collates available sensitivity and thermal analysis data for diazo transfer reagents and diazo compounds to act as an accessible reference resource. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and accelerating rate calorimetry (ARC) data for the model donor/acceptor diazo compound ethyl (phenyl)diazoacetate are presented. We also present a rigorous DSC dataset with 43 other diazo compounds, enabling direct comparison to other energetic materials to provide a clear reference work to the academic and industrial chemistry communities. Interestingly, there is a wide range of onset temperatures (Tonset) for this series of compounds, which varied between 75 and 160 °C. The thermal stability variation depends on the electronic effect of substituents and the amount of charge delocalization. A statistical model is demonstrated to predict the thermal stability of differently substituted phenyl diazoacetates. A maximum recommended process temperature (TD24) to avoid decomposition is estimated for selected diazo compounds. The average enthalpy of decomposition (?"HD) for diazo compounds without other energetic functional groups is-102 kJ mol-1. Several diazo transfer reagents are analyzed using the same DSC protocol and found to have higher thermal stability, which is in general agreement with the reported values. For sulfonyl azide reagents, an average ?"HD of-201 kJ mol-1 is observed. High-quality thermal data from ARC experiments shows the initiation of decomposition for ethyl (phenyl)diazoacetate to be 60 °C, compared to that of 100 °C for the common diazo transfer reagent p-acetamidobenzenesulfonyl azide (p-ABSA). The Yoshida correlation is applied to DSC data for each diazo compound to provide an indication of both their impact sensitivity (IS) and explosivity. As a neat substance, none of the diazo compounds tested are predicted to be explosive, but many (particularly donor/acceptor diazo compounds) are predicted to be impact-sensitive. It is therefore recommended that manipulation, agitation, and other processing of neat diazo compounds are conducted with due care to avoid impacts, particularly in large quantities. The full dataset is presented to inform chemists of the nature and magnitude of hazards when using diazo compounds and diazo transfer reagents. Given the demonstrated potential for rapid heat generation and gas evolution, adequate temperature control and cautious addition of reagents that begin a reaction are strongly recommended when conducting reactions with diazo compounds.
- Green, Sebastian P.,Wheelhouse, Katherine M.,Payne, Andrew D.,Hallett, Jason P.,Miller, Philip W.,Bull, James A.
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supporting information
p. 67 - 84
(2020/01/31)
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- Preparation of Organic Nitrates from Aryldiazoacetates and Fe(NO3)3·9H2O
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A thermal protocol is reported for the formal insertion of nitric acid into aryldiazoacetates using Fe(NO3)3·9H2O. This strategy is mild and high yielding and allows the preparation of a large variety of members of an unprecedented family of organic nitrates. The nitrate group can be also readily transformed into other functional groups and heterocyclic moieties and can possibly allow new biological explorations of untapped potential associated with their NO-releasing ability.
- Thurow, Samuel,Fernandes, Alessandra A. G.,Quevedo-Acosta, Yovanny,De Oliveira, Matheus F.,De Oliveira, Marcelo G.,Jurberg, Igor D.
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p. 6909 - 6913
(2019/09/12)
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- ARTIFICIAL METALLOENZYMES CONTAINING NOBLE METAL-PORPHYRINS
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The present invention is drawn to artificial metalloenzymes for use in cyclopropanation reactions, amination and C—H insertion.
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Paragraph 0240
(2018/11/21)
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- Chlorotrimethylsilane and Sodium Iodide: A Useful Combination for the Regioselective Deoxygenation of Arylalkyl-α-Diketones
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An efficient regioselective deoxygenation of arylalkyl-1,2-diketones by the couple trimethylsilylchloride/sodium iodide has been reported. In all cases, the deoxygenation takes place on the carbonyl group (Cα=O) proximal to the aromatic ring in methylene chloride at room temperature in good yields, furnishing a series of variously functionalized alkylbenzylketones. A large range of functional groups were well tolerated on the ortho-, meta- and para-positions by this mild process regardless of their electronic effects, demonstrating the general character of the present methodology. The trimethylsilylchloride/sodium iodide reducing process was also successfully applied to reduce α-ketoacid and α-ketoester substrates. (Figure presented.).
- Yuan, Ling-Zhi,Zhao, Guangkuan,Hamze, Abdallah,Alami, Mouad,Provot, Olivier
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p. 2682 - 2691
(2017/08/16)
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- Mechanistic studies on gold-catalyzed direct arene c-h bond functionalization by carbene insertion: The coinage-metal effect
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The catalytic functionalization of the Csp2-H bond of benzene by means of the insertion of the CHCO2Et group from ethyl diazoacetate (N2= CHCO2Et) has been studied with the series of coinage-metal complexes IPrMCl (IPr = 1,3-bis- (diisopropylphenyl)imidazol-2-ylidene) and NaBArF 4 (BArF 4 = tetrakis(3,5-bis(trifluoromethyl)phenyl)borate). For Cu and Ag, these examples constitute the first use of such metals toward this transformation, which also provides ethyl cyclohepta-2,4,6-trienecarboxylate as a byproduct from the so-called Buchner reaction. In the case of methyl-substituted benzenes, the reaction exclusively proceeds onto the aromatic ring, the Csp3-H bond remaining unreacted. A significant coinage-metal effect has been observed, since the gold catalyst favors the formation of the insertion product into the Csp2-H bond whereas copper and silver preferentially induce the formation of the cycloheptatriene derivative. Experimental studies and theoretical calculations have explained the observed selectivity in terms of the formation of a common Wheland intermediate, resembling an electrophilic aromatic substitution, from which the reaction pathway evolves into two separate routes to each product.
- Fructos, Manuel R.,Besora, Maria,Braga, Ataualpa A. C,Díaz-Requejo, M. Mar,Maseras, Feliu,Perez, Pedro J.
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p. 172 - 179
(2017/04/04)
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- Iron and manganese catalysts for the selective functionalization of arene C(sp2)-H bonds by carbene insertion
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The first examples of the direct functionalization of non-activated aryl sp2 C-H bonds with ethyl diazoacetate (N2CHCO2Et) catalyzed by Mn- or Fe-based complexes in a completely selective manner are reported, with no formation of the frequently observed cycloheptatriene derivatives through competing Buchner reaction. The best catalysts are FeII or MnII complexes bearing the tetradentate pytacn ligand (pytacn= 1-(2-pyridylmethyl)-4,7-dimethyl-1,4,7-triazacyclononane). When using alkylbenzenes, the alkylic C(sp3)-H bonds of the substituents remained unmodified, thus the reaction being also selective toward functionalization of sp2 C-H bonds. Exclusive catalysis: Iron- and-manganese-based catalysts selectively functionalize the C(sp2)-H bonds of benzene or alkylbenzenes through the formal insertion of the CHCO2Et group from N2CHCO2Et (see scheme). When using alkylbenzenes, the alkylic C(sp3)-H bonds of the substituents remain unmodified.
- Conde, Ana,Sabenya, Gerard,Rodríguez, Mònica,Postils, Verònica,Luis, Josep M.,Díaz-Requejo, M. Mar,Costas, Miquel,Pérez, Pedro J.
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supporting information
p. 6530 - 6534
(2016/06/01)
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- Novel synthesis of benzofuran- and indol-2-yl-methanamine derivatives
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We report on a novel synthesis towards benzofuran-2-yl-methanamine and indol-2-yl-methanamine derivatives by using ortho-methoxy and ortho-nitro substituted phenylacetic acids as starting material, respectively. For each compound series, a key intermediate bearing the oxazole-4-carboxylic acid methylester moiety was produced. Refluxing the ortho-methoxy series in HBr/HAc produced the desired benzofuran-2-yl-methanamines. Accordingly, for the synthesis of indoles the nitro-group was first reduced and refluxing these intermediates in HCl gave the corresponding indol-2-yl-methanamines. The method worked well with electron donating substituents. Limitations regarding electron withdrawing substituents are discussed. This straightforward synthetic procedure can be a useful approach to generate a variety of substituted benzofuran-2-yl-methanamine and indol-2-yl-methanamine compounds by starting from readily available phenylacetic acid derivatives.
- Schlosser, Joachim,Johannes, Eugen,Zindler, Melanie,Lemmerhirt, Jan,Sommer, Benjamin,Schütt, Martin,Peifer, Christian
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supporting information
p. 89 - 94
(2015/02/02)
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- Alcohol assisted C-C bond breaking: Copper-catalyzed deacetylative α-arylation of β-keto esters and amides
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A method of alcohol-assisted copper-catalyzed highly selective deacetylative α-arylation of β-keto esters and amides has been demonstrated, which illustrated an efficient example of achieving α-aryl esters and amides. From the synthetic point of view, this arylation protocol is general and practical, representing a simple way to produce α-arylated carbonyl compounds from basic starting materials at low cost.
- Ke, Jie,He, Chuan,Liu, Huiying,Xu, Huan,Lei, Aiwen
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supporting information
p. 6767 - 6769
(2013/07/26)
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- Synthesis of arylacetates from benzylic alcohols and oxalate esters through decarboxylative coupling
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Follow that dream: By combining a reversible transesterification between benzylic alcohols and dialkyl oxalates with catalytic decarboxylation of the resulting esters, a regiospecific C-C-bond-forming reaction to give α-arylacetates was achieved. In the overall process, CO2 and a volatile alcohol are the only byproducts. Various α-arylacetates were thus synthesized in high yields from easily accessible starting materials in the presence of catalytic amounts of Pd(OAc)2, dppp, and DABCO (see scheme). Copyright
- Gruenberg, Matthias F.,Goossen, Lukas J.
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supporting information
p. 7334 - 7337
(2013/06/27)
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- Pd-catalyzed decarboxylative cross-couplings of potassium malonate monoesters with aryl halides
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An efficient catalytic protocol for Pd-catalyzed decarboxylative cross-coupling of potassium malonate monoesters and derivatives with aryl bromides and chlorides are described. Because of its broad applicability, this new catalytic system provides an alternative method for the preparation of diverse aryl acetic acids and derivatives.
- Feng, Yi-Si,Wu, Wei,Xu, Zhong-Qiu,Li, Yan,Li, Ming,Xu, Hua-Jian
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experimental part
p. 2113 - 2120
(2012/03/26)
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- COMPOUNDS FOR THE TREATMENT OF CNS DISORDERS
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The invention relates to novel cycloalkyl- or cycloalkenyl-substituted pyrazolopyrimidinones of formula (I), wherein ā is selected from the group A1 consisting of a C3-C8-cycloalkyl group or a C4-C8-cycloalkenyl group, whereby the members of C3-C8-cycloalkyl group being selected from the group of cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptanyl and cyclooctanyl; and the members of the C4-C8-cycloalkenyl group, being selected from cyclobutenyl, cyclopentenyl, cyclohexenyl, cycloheptenyl, cyclooctenyl, cyclopentadienyl, cyclohexadienyl, cycloheptadienyl, cyclooctadienyl, cycloheptatrienyl, cyclooctathenyl, cyclooctatetraenyl. The new compounds shall be used for the manufacture of medicaments, in particular medicaments for improving perception, concentration, learning and/or memory in patients in need thereof. Chemically, the compounds are characterised as pyrazolopyrimidinones with a cycloalkyl-moiety directly bound to the 1 position of the pyrazolopyrimidinone and a second substituent in the 6 position which is bound via an optionally substituted methylene-bridge. Further aspects of the present invention refer to a process for the manufacture of the compounds and their use for producing medicaments.
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Page/Page column 42
(2012/05/20)
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- Synthesis of α-Aryl nitriles through palladium-catalyzed decarboxylative coupling of cyanoacetate salts with aryl halides and triflates
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Worth its salt: The palladium-catalyzed decarboxylative coupling of the cyanoacetate salt as well as its mono- and disubstituted derivatives with aryl chlorides, bromides, and triflates is described (see scheme). This reaction is potentially useful for the preparation of a diverse array of α-aryl nitriles and has good functional group tolerance. S-Phos=2-(2,6- dimethoxybiphenyl)dicyclohexylphosphine), Xant-Phos=4,5-bis(diphenylphosphino)- 9,9-dimethylxanthene. Copyright
- Shang, Rui,Ji, Dong-Sheng,Chu, Ling,Fu, Yao,Liu, Lei
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supporting information; experimental part
p. 4470 - 4474
(2011/06/24)
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- Synthesis of the isoquinocycline-pyrrolopyrrole substructure
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The synthesis of the pyrrolopyrrole substructure of the isoquinocyclines is reported. The pentacyclic (CDEFG) substructure of isoquinocycline A and B, which contains an unusual 2,4,5,6-tetrahydropyrrolo[2,3-b]pyrrole (FG) connected via an N,O-spiro acetal to the anthraquinoid core of the isoquinocycline aglycon has been synthesized. Key steps were a nickel(0)-mediated hydrocyanation of an alkynone, the conversion of an O,O-acetal into an N,O-acetal, and an intramolecular amidine alkylation.
- Cordes, Jens,Harms, Klaus,Koert, Ulrich
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supporting information; experimental part
p. 3808 - 3811
(2010/10/21)
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- Enzymatic desymmetrization of prochiral 2-substituted-1,3-diamines: Preparation of valuable nitrogenated compounds
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A wide range of prochiral 1, 3-diamines were first efficiently synthesized and subsequently desymmetrized by using lipase from Pseudomonas cepacia as catalyst and diallyl carbonate as alkoxycarbonylating agent. In all cases, the amino carbamates of R-configuration were recovered. Final selective cleavage of the N-allyloxycarbonyl moiety was carried out under mild reaction conditions, which demonstrates the high versatility and potential of this chemoenzymatic route as a source of intermediates in the synthesis of related optically active nitrogenated derivatives.
- Rios-Lombardia, Nicolas,Busto, Eduardo,Garcia-Urdiales, Eduardo,Gotor-Fernandez, Vicente,Gotor, Vicente
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supporting information; experimental part
p. 2571 - 2574
(2009/07/25)
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- 1-HETEROCYCLYL-1,5-DIHYDRO-PYRAZOLO[3,4-D] PYRIMIDIN-4-ONE DERIVATIVES AND THEIR USE AS PDE9A MODULATORS
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The invention relates to novel 1,6-disubstituted pyrazolopyrimidinones, Formula (I) with Hc is a mono-, bi- or tricyclic heterocyclyl group, the ring members of which are carbon atoms and at least 1, preferably 1, 2 or 3, heteroatom(s), which are selected from the group of nitrogen, oxygen and sulphur, which is in the form of -S(O)r - with r being 0, 1 or 2, and - said heterocyclyl group is or comprises 1 non-aromatic, saturated, or partly unsaturated monocyclic ring which comprises at least 1 heteroatom as ring member and - said heterocyclyl group is bound to the scaffold by said 1 non- aromatic, saturated, or partly unsaturated monocyclic ring which comprises at least 1 heteroatom as ring member. According to one aspect of the invention the new compounds are for the manufacture of medicaments, in particular medicaments for the treatment of conditions concerning deficits in perception, concentration, learning or memory. The new compounds are also for the manufacture of medicaments for the treatment of Alzheimer's disease.
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Page/Page column 163; 165
(2009/10/30)
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- Remarkable co-catalysis by copper(I) oxide in the palladium catalyzed cross-coupling of arylboronic acids with ethyl bromoacetate
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Copper(I) oxide can effectively co-catalyze the Suzuki type cross-coupling reactions of arylboronic acids with ethyl bromoacetate. As an alternative protocol for introducing the methylenecarboxy group into functionalized molecules, this reaction occurs in
- Liu, Xing-Xin,Deng, Min-Zhi
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p. 622 - 623
(2007/10/03)
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- IODIDE ION PROMOTION BENZYL CHLORIDE-BORATE ESTER CARBONYLANION REACTIONS
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Esters are isolated in fine yields from the rhodium(I) catalyzed reaction of benzyl chlorides with borate esters and carbon monoxide, in the presence of potassium iodide.
- Alper, Howard,Hamel, Nathalie,Smith, David J. H.,Woell, James B.
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p. 2273 - 2274
(2007/10/02)
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- Palladium-catalyzed Displacement of Aryl Halide by Tin Analogue of Reformatsky Reagent
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Reaction of ethyl α-(tributylstannyl)acetate with aryl bromides in the presence of zinc bromide or chloride and a catalytic amount of dichlorobis(tri-o-tolylphosphine)palladium was found to give ethyl arylacetates in good yields except with the aryl bromide having p-acetyl or p-nitro group.
- Kosugi, Masanori,Negishi, Yoshikazu,Kameyama, Masayuki,Migita, Toshihiko
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p. 3383 - 3384
(2007/10/02)
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