- Preparation method and application of chiral spiro aminophosphine ligand with substituent at 3-position of pyridine ring
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The invention relates to a preparation method and application of a chiral spiro aminophosphine ligand with a substituent at the 3-position of a pyridine ring. The chiral spiro aminophosphine ligand isa compound shown as a formula 1, or a racemate or an op
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Paragraph 0057-0060; 0064
(2020/02/14)
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- General access to C-centered radicals: Combining a bioinspired photocatalyst with boronic acids in aqueous media
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Carbon-centered radicals are indispensable building blocks for modern synthetic chemistry. In recent years, visible light photoredox catalysis has become a promising avenue to access C-centered radicals from a broad array of latent functional groups, including boronic acids. Herein, we present an aqueous protocol wherein water features a starring role to help transform aliphatic, aromatic, and heteroaromatic boronic acids to C-centered radicals with a bioinspired flavin photocatalyst. These radicals are used to deliver a diverse pool of alkylated products, including three pharmaceutically relevant compounds, via open-shell conjugate addition to disparate Michael acceptors. The mechanism of the reaction is investigated by computational studies, deuterium labeling, radical-trapping experiments, and spectroscopic analysis.
- Bloom, Steven,Chilamari, Maheshwerreddy,Immel, Jacob R.
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p. 12727 - 12737
(2020/11/18)
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- Unnatural α-amino ethyl esters from diethyl malonate or ethyl β-bromo-α-hydroxyiminocarboxylate
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We have explored here the scope of the age-old diethyl malonate-based accesses to α-amino esters involving Knoevenagel condensations of diethyl malonate on aldehydes, reductions of the resulting alkylidenemalonates, the preparation of the corresponding α-hydroxyimino esters and their final reduction. This synthetic pathway turned out to be general although some unexpected limitations were encountered. The synthetic modifications of some of the intermediates - using Suzuki-Miyaura coupling or cycloadditions - before undertaking the oximation step - provided accesses to further α-amino esters. Moreover, other pathways to α-hydroxyimino esters were explored including an attempt to improve the cycloadditions between ethyl β-bromo-α-hydroxyiminocarboxylate and various alkylfuranes.
- Coutant, Eloi P.,Hervin, Vincent,Gagnot, Glwadys,Ford, Candice,Baatallah, Racha,Janin, Yves L.
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supporting information
p. 2853 - 2860
(2018/11/26)
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- IMIDAZOPYRAZINE DERIVATIVES, PROCESS FOR PREPARATION THEREOF, AND THEIR USES AS LUCIFERINS
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The present invention is in the field of bioluminescence in biology and/or medicine. In particular, the invention provides imidazopyrazine derivatives, processes for preparation thereof, and their uses as luciferins.
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Page/Page column 59-60
(2018/11/22)
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- Fe(HSO4)3 : An efficient, heterogeneous and reusable catalyst for C-alkylation of β-dicarbonyl compounds
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Fe(HSO4)3(FHS) was used as an efficient catalyst for the heterogeneous addition of a series of benzylic and allylic alcohols to various β-dicarbonyl compounds, which afforded moderate to excellent yields of C-alkylated products in 1,2-dichloroethane. In comparison with the previous methods, the present research surprisingly exhibited higher reaction yields without formation of any by-products which could be formed by self-condensation of alcohols. Moreover, the catalyst can be readily recovered and reused up to five times with almost maintained reactivity and yields.
- Khafajeh, Samaneh,Akhlaghinia, Batool,Rezazadeh, Soodabeh,Eshghi, Hossein
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p. 1903 - 1912
(2015/02/05)
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- Mixed Dialkylaluminum Chlorides and Mixed Trimethylorganoaluminates in Chemoselective 1,4 Addition Reactions to Alkylidene Malonic Acid Diethyl Ester
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Mixed alkyl-methyl- and aryl-methylorganoaluminum chlorides 6 were formed by reaction of methylaluminum dichloride with organolithium or Grignard compounds and used for chemoselective 1,4 addition of higher alkyl, aryl, alkenyl and alkinyl groups to alkylidine malonic esters 1 and 2. As an alternative, mixed trimethylorganoaluminates 7 can also be applied for these Michael addition reactions. For conjugate addition of alkenyl groups to alkylidene malonates 1 and 2, alkenyl diisopropylalanes 10 obtained from alkynes and diisopropylaluminum hydride proved the most efficient reagents. Using these novel mixed organoaluminum compounds, β-branched malonic (carboxylic) acid derivatives 3c, 8, 9 and 11 were obtained in good yields. The method offers a general access to β-branched carboxylic derivatives of quite diverse structure not dependent on the commercial availability of the organoluminum chlorides.
- Maas, Steffen,Kunz, Horst
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p. 396 - 403
(2007/10/03)
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- Asymmetric conjugate 1,4-addition of arylboronic acids to α,β-unsaturated esters catalyzed by rhodium(I)/(S)-binap
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Arylboronic acids underwent the conjugate 1,4-addition to α,β-unsaturated esters to give β-aryl esters in high yields in the presence of a rhodium(I) catalyst. The addition of arylboronic acids to isopropyl crotonate resulted in high yields and high enantioselectivity exceeding 90% ee in the presence of 3 mol % of Rh(acac)(C2H4)2 and (S)-binap at 100 °C. The rhodium/(S)-binap complex provided (R)-3-phenylbutanoate in the addition of phenylboronic acid to benzyl crotonate. The effects on the enantioselectivity of chiral phosphine ligands, rhodium precursors, and substituents on α,β-unsaturated esters are discussed, as well as the mechanistic aspect of the catalytic cycle.
- Sakuma, Satoshi,Sakai, Masaaki,Itooka, Ryoh,Miyaura, Noria
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p. 5951 - 5955
(2007/10/03)
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- Conjugate addition of dialkylaluminum chlorides to alkylidenemalonic acid derivatives
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Complete regioselectivity is achieved in conjugate addition reactions of dialkylaluminum chlorides with alkylidenemalonic esters, alkylidenecyanoacetates, and alkylidenemalonodinitrile to give β-branched carboxylic acid derivatives. Sterically demanding products containing quaternary carbon atoms are obtained in good yields. In the case of diethylaluminum chloride, accompanying reductions of the substrates can be suppressed by application of boron trifluoride as an assisting Lewis acid.
- Maas, Steffen,Stamm, Armin,Kunz, Horst
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p. 1792 - 1798
(2007/10/03)
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- Use of the Nonionic Superbase P(MeNCH2CH2)3N in the Selective Monoalkylation of Active-Methylene Compounds
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The symmetric active-methylene compounds CH2(CO2Et)2 and CH2[C(O)Me]2 are selectively monoalkylated in the presence of 1.1 equiv of a variety of alkyl halides and 1 equiv of the nonionic Superbase P(MeNCH2CH2)2N in 85-98% yields in 30 min at room temperature. The unsymmetrical active-methylene compound EtO2CCH2C(O)Me is selectively monoalkylated under the same conditions, except for the temperature, which is 0 °C, in 59-88% yields. The observation of selective C- rather than O-alkylation is rationalized in terms of the formation of an enolate whose negatively charged oxygen is sterically protected by a nearby HP(MeNCH2CH2)2N+ counterion in a tight ion pair.
- Arumugam, Subramaniam,McLeod, Dale,Verkade, John G.
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p. 3677 - 3679
(2007/10/03)
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- Specific Features of Reactions of Butyl- and Phenylacetylenes with CH-Acids
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The reactions of butyl- and phenylacetylenes with cyanoacetic, malonic, and acetoacetic esters and acetylacetone in a polar solvent in the presence of mercuric acetate were studied. Intramolecular cyclization of unsaturated dicarbonyl compounds formed at
- Badanyan,Chobanyan,Tirakyan,Danielyan
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- New dual inhibitors of neutral endopeptidase and angiotensin-converting enzyme: Rational design, bioavailability, and pharmacological responses in experimental hypertension
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In the treatment of cardiovascular diseases, it could be of therapeutic interest to associate the hypotensive effects resulting from the inhibition of angiotensin II formation, ensured by endothelial angiotensin-converting enzyme (ACE), with the diuretic
- Fournie-Zaluski,Coric,Turcaud,Rousselet,Gonzalez,Barbe,Pham,Jullian,Michel,Roques
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p. 1070 - 1083
(2007/10/02)
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- Synthesis of Substituted Tetrahydronaphthalenes by Mn(III), Ce(IV), and Fe(III) Oxidation of Substituted Diethyl α-Benzylmalonates in the Presence of Olefins
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The oxidation of substituted diethyl α-benzylmalonates (1a-m) by manganese(III) acetate in acetic acid, cerium(IV) ammonium nitrate in methanol, or iron(III) perchlorate in acetonitrile in the presence of substituted olefins 2a-u was investigated.The results are consistent with a common mechanism.It involves selective generation of malonyl radicals from high-valent metal malonyl complexes, their addition to the olefin, and competition of the adduct radical between intramolecular cyclization to produce highly functionalized tetrahydronaphthalenes (3) and oxidation bymetal salt to give mainly γ-lactones (5).Several electron-withdrawing and releasing substituents on the aromatic ring and on the olefin can be successfully used in the synthesis of 3 without olefin telomerization.The influence of metal and olefin or aromatic substituents on the homolytic addition and intramolecular aromatic substitution is discussed.
- Citterio, Attilio,Sebastiano, Roberto,Marion, Antonio,Santi, Roberto
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p. 5328 - 5335
(2007/10/02)
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- ORGANOMANGANESE (II) REAGENTS XV. CONJUGATE ADDITION OF ORGANOMANGANESE REAGENTS TO ALKYLIDENEMALONIC ESTERS AND RELATED COMPOUNDS
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Organomanganese reagents react with alkylidenemalonic esters or related compounds to give the conjugate addition products in good yields.Several examples illustrate the scope and the efficiency of this reaction.
- Cahiez, Gerard,Alami, Mouad
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p. 4163 - 4176
(2007/10/02)
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- Synthesis of 3-Phenoxybenzyl 3-Alkyl-3-phenyl-/p-substituted phenyl and 3-Phenoxybenzyl 2-Alkyl-3-phenyl-/p-substituted phenylpropionates
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Some 3-phenoxybenzyl 3-alkyl-3-phenyl-/p-substituted phenylpropionates (VII, XI, XV, XIX, XXIII, XXVII) which resemble structurally the 1,2-secopyrethroids, have been prepared employing simple reactions like alkylation, decarbethoxylation and transesterification.The synthesis of 3-phenoxybenzyl 2-alkyl-3-phenyl-/p-substituted phenyl-propionates (XXXI, XXXII, XXXIII, and XXXVI) bearing close structural resemblance to 2,3-secopyrethroids has also been described.
- Kelkar, S. V.,Joshi, G. S.,Kulkarni, G. H.,Mitra, R. B.
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