- Asymmetric and Geometry-Selective α-Alkenylation of α-Amino Acids
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Both E- and Z-N′-alkenyl urea derivatives of imidazolidinones may be formed selectively from enantiopure α-amino acids. Generation of their enolate derivatives in the presence of K+ and [18]crown-6 induces intramolecular migration of the alkeny
- Abas, Hossay,Mas-Roselló, Josep,Amer, Mostafa Mahmoud,Durand, Derek J.,Groleau, Robin R.,Fey, Natalie,Clayden, Jonathan
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supporting information
p. 2418 - 2422
(2019/02/09)
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- Diastereoselective [2,3]-Sigmatropic Rearrangement of N-Allyl Ammonium Ylides
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A rapid and diastereoselective method was developed for the [2,3]-sigmatropic rearrangement of N-Allyl ammonium ylides, affording products in up to 95percent isolated yields and up to 97:3 dr; most of the desired products were formed within 1 minute. For
- Erkman, Kristin,J?rving, Ivar,Kaabel, Sandra,Kanger, T?nis,Murre, Aleksandra
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p. 4183 - 4197
(2019/11/14)
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- Access to functionalized imidazolidin-2-one derivatives by Iron-catalyzed oxyamination of alkenes
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Functionalized imidazolidin-2-one were prepared by using an iron-catalyzed alkene oxyamination reaction. Hy-droxylamine derivatives were used in this atom-economical process, and the addition of an external oxidant was not required. The conditions developed were shown to be efficient for mono-, di-, and trisubstituted double bonds, and a large scope of diamino alcohol precursors were delivered in good yields with good diastereoselectivities. The mechanistic pathway was studied and appears to involve both a fused aziridine and a carbocationic species.
- Manick, Anne-Doriane,Aubert, Sidonie,Yalcouye, Boubacar,Prangé, Thierry,Berhal, Farouk,Prestat, Guillaume
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p. 11485 - 11492
(2018/10/20)
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- Method for preparing naftifine hydrochloride
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The invention provides a method for preparing naftifine hydrochloride. The finished naftifine hydrochloride is obtained through subjecting relatively-cheap cinnamyl alcohol, which serves as a raw material, to chlorinating-reagent chlorinating, methyl-amination and 1-chloromethyl naphthalene substitution sequentially, and finally, carrying out acidification salt-forming and crystallization refining. According to the method provided by the invention, all intermediates in first three steps of reactions are subjected to a reaction without purification, process flows are continuous and non-intermittent, the operation is simplified, the yield and production efficiency of the product are increased, and meanwhile, the purity of the product is ensured, so that the method is applicable to industrialization; and meanwhile, the method has the advantages of simple reaction conditions, low cost and environment-friendliness.
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- Aryne-Mediated [2,3]-Sigmatropic Rearrangement of Tertiary Allylic Amines
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A new strategy has been established for the [2,3]-sigmatropic rearrangement of quaternary allylic ammonium ylides via in situ activation of tertiary allylic amines with arynes under mild conditions. Using 2-(trimethylsilyl)aryl triflates as aryne precurso
- Zhang, Juan,Chen, Zhi-Xiong,Du, Ting,Li, Bing,Gu, Yonghong,Tian, Shi-Kai
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supporting information
p. 4872 - 4875
(2016/10/18)
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- Synthesis of enantiomerically enriched imidazolidin-2-ones through asymmetric palladium-catalyzed alkene carboamination reactions
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Positive water effect: A catalyst composed of [Pd2(dba) 3] (dba=dibenzylideneacetone) and (S)-Siphos-PE is effective for the enantioselective coupling of N-allyl ureas with aryl bromides to afford 4-substituted imidazolidin-2-ones. Added water leads to significantly improved enantioselectivities with electron-poor aryl halide substrates. It is suggested that the C-C bond-forming reductive elimination is the enantiodetermining step in these reactions. Copyright
- Hopkins, Brett A.,Wolfe, John P.
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supporting information
p. 9886 - 9890
(2012/10/29)
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- Antifungal amine derivatives and processing for producing the same
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Novel amine derivatives having an excellent antimycotic effect represented by general formula (1) below and salts thereof are provided. [in the formula (1, R1represents a C1-5alkyl group which may be halogenated, R2represents 4-(1,1-dimethylalkyl)benzyl group, 4-(1-methyl-phenylethyl)benzyl group, 1-or 2-naphthylmethyl group, or a hydrocarbon group having 3,3-dimethyl-1-butynyl group or a phenyl group at its terminal and 1 to 3 double bonds; R3represents oxygen atom or a methylene group which may be substituted by a C1-4alkyl group; and R4represents 1-or 2 naphthyl group or a phenyl group which may be substituted.
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- Photophysical and photochemical behavior of intramolecular-styrene-amine exciplexes
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The photophysical and photochemical behavior of a series of secondary and tertiary ω-(β-styryl)aminoalkanes with one to five methylenes separating the styryl and amino groups has been investigated and compared to the intermolecular reactions of 1-phenylpropene with secondary and tertiary amines. The tertiary styrylamines form fluorescent intramolecular exciplexes, but fail to undergo intramolecular addition reactions. Both the rate constant for exciplex formation and the stability of the exciplex are dependent upon the length of the polymethylene chain connecting the chromophores. The failure of the tertiary amine exciplexes to undergo intramolecular addition is attributed to an unfavorable exciplex geometry for α-C-H transfer to the styrene double bond. While the secondary styrylamines do not form fluorescent exciplexes, the dependence of the styrene singlet lifetime upon the polymethylene chain length is similar to that for the tertiary styrylamines. Intramolecular N-H addition to the styrene double bond results in the formation of two regioisomeric (α-phenyl and α-benzyl) cyclic amines of different ring size. The regioisomer of larger ring size is favored except in the case in which four methylenes separate the chromophores. The effects of polymethylene chain length, solvent polarity, temperature, and the bulk of the N-alkyl group upon product yields and ratios are discussed in terms of a mechanism involving singlet exciplex and biradical intermediates.
- Lewis, Frederick D.,Dasharatha Reddy,Schneider, Siegfried,Ga, Michael
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p. 3498 - 3506
(2007/10/02)
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- Heterocyclisations radicalaires d'aminothiols ethyleniques. II - Etude de l'influence des substituants de la double liaison sur l'orientation de la cyclisation
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Free radical initiation of N-allyl-2-aminothiols 1-6 bearing substituents on the double bond give a mixture of thiazolidines and thiomorpholines.The more substituted the double bond the higher is the ratio of thiomorpholine/thiazolidine.To rationalize the
- Crozet, Michel P.,Kaafarani, Mustapha,Surzur, Jean-Marie
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p. 390 - 398
(2007/10/02)
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- ANOMALOUS STEREOCHEMISTRY IN THE WITTIG REACTION INDUCED BY NUCLEOPHILIC GROUPS IN THE PHOSPHONIUM YLIDE
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Reaction of ylides from 3-9 with benzaldehyde show that carboxylate and oxido functionalities proximate to the ylide center promote anomalously high E stereoselectivity in alkene formation.Through the use of α-deuterated ylides 12-14, an internal "trans-selective Wittig" mechanism was ruled out as a principal source of exaggerated E alkene production.
- Maryanoff, Bruce E.,Duhl-Emswiler, B. A.,Reitz, Allen B.
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p. 187 - 190
(2007/10/02)
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