186800-76-0Relevant academic research and scientific papers
Practical N-hydroxyphthalimide-mediated oxidation of sulfonamides to N-sulfonylimines
Wang, Jian,Yi, Wen-Jing
, (2019/11/02)
A new method to prepare sulfonylimines through the oxidation of sulfonamides mediated by N-hydroxyphthalimide under mild conditions has been developed. Compared to reported oxidation methods, broader substrates scope and milder conditions were achieved in
Nitroxyl-Radical-Catalyzed Oxidative Coupling of Amides with Silylated Nucleophiles through N-Halogenation
Moriyama, Katsuhiko,Kuramochi, Masako,Fujii, Kozo,Morita, Tsuyoshi,Togo, Hideo
supporting information, p. 14546 - 14551 (2016/11/23)
A nitroxyl-radical-catalyzed oxidative coupling reaction between amines with an N-protecting electron-withdrawing group (EWG) and silylated nucleophiles was developed to furnish coupling products in high yields, thus opening up new frontiers in organocatalyzed reactions. This reaction proceeded through the activation of N-halogenated amides by a nitroxyl-radical catalyst, followed by carbon–carbon coupling with silylated nucleophiles. Studies of the reaction mechanism indicated that the nitroxyl radical activates N-halogenated amides, which are generated from N-EWG-protected amides and a halogenation reagent, to give the corresponding imines.
Stereoselective synthesis of activated 2-arylazetidines via imino-aldol reaction
Ghorai, Manas K.,Das, Subhomoy,Das, Kalpataru,Kumar, Amit
, p. 9042 - 9049 (2015/09/01)
A simple and efficient synthetic route to substituted N-sulfinyl and N-sulfonyl azetidines is described involving imino-aldol reaction of ester enolates with racemic and non-racemic aldimines for obtaining β-amino esters as a key step. These β-amino ester
Synthesis of 1,6-dihydropyrimidines via copper-catalyzed multistep cascade reactions between O-propargylic aldoximes and isocyanates
Nakamura, Itaru,Onuma, Toshiki,Zhang, Dong,Terada, Masahiro
, p. 1178 - 1182 (2014/02/14)
Multi-step cascade reactions of O-propargylic oximes with isocyanates were carried out in the presence of copper catalysts to afford the corresponding 1,6-dihydropyrimidines in good yields. The multi-step reactions consisted of a 2,3-rearrangement, a [3+2] cycloaddition, decarboxylative ring opening involving a 1,4-hydrogen shift, and a 6π-electrocyclization.
Rh-catalyzed C-C cleavage of benzyl/allylic alcohols to produce benzyl/allylic amines or other alcohols by nucleophilic addition of intermediate rhodacycles to aldehydes and imines
Zhang, Xi-Sha,Li, Yang,Li, Hu,Chen, Kang,Lei, Zhi-Quan,Shi, Zhang-Jie
, p. 16214 - 16225 (2013/02/21)
We report three transformations: 1) direct transformation from biarylmethanols into biarylmethylamines; 2) direct transformation from one biarylmethanol into another biarylmethanol; 3) direct transformation from allylic alcohols into allylic amines. These transformations are based on pyridyl-directed Rh-catalyzed C-C bond cleavage of secondary alcohols and subsequent addition to C=X (X=N or O) double bonds. The reaction conditions are simple and no additive is required. The driving force of C-C bond cleavage is the formation of the stable rhodacycle intermediate. Other directing groups, such as the pyrazolyl group, can also be used although it is not as efficient as the pyridyl group. We carried out in-depth investigations for transformation 1 and found that: 1) the substrate scope was broad and electron-rich alcohols and electron-deficient imines are more efficient; 2) as the leaving group, aldehyde had no significant impact on either the C-C bond cleavage or the whole transformation; 3) mechanistic studies (intermediate isolation, in situ NMR spectroscopic studies, competing reactions, isotopic labeling experiments) implied that: i) The C-C cleavage was very efficient under these conditions; ii) there is an equilibrium between the rhodacycle intermediate and the protonated byproduct phenylpyridine; iii) the addition step of the rhodacycle intermediate to imines was slower than the C-C cleavage and the equilibrium between the rhodacycle and phenylpyridine; iv) the whole transformation was a combination of two sequences of C-C cleavage/nucleophilic addition and C-C cleavage/protonation/C-H activation/nucleophilic addition, with the latter being perhaps the main pathway. We also demonstrated the first example of cleavage of an C(alkenyl)-C(benzyl) bond. These transformations showed the exchange (or substitution) of the alcohol group with either an amine or another alcohol group. Like the "group transplant", this method offers a new concept that can be used to directly synthesize the desired products from other chemicals through reorganization of carbon skeletons.
NEW DIOXOMORPHOLINES FOR COMBATING ENDOPARASITES
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Page/Page column 21; 22, (2008/06/13)
The present invention relates to new dioxomorpholines, to their use for combating endoparasites and to processes for their preparation.
α-Amino acids and N-protected α-amino aldehydes by stereoselective additions of a chiral vinyllithium reagent to sulfonylimines
Braun, Manfred,Opdenbusch, Kersten
, p. 141 - 154 (2007/10/03)
The chiral vinyllithium reagent (S)-1b, readily generated from dibromoalkene (S)-1a by bromine/lithium exchange, adds stereoselectively to mesitylsulfonylimines 2a-f so that the diastereomers 3 are obtained in ≥98% d.e. after column chromatography. The bromoalkenes 3a-d are submitted to ozonolysis in methanol to give α-mesitylsulfonylamino esters (S)-8a-d which can be hydrolyzed to deliver N-protected α- amino acids in >95% e.e. On the other hand, α-mesitylsulfonylamino aldehydes 12a-d are available when bromoalkenes 3a, d-f are first debrominated (→ 11a-d) and subsequently ozonized. In order to avoid reacemization, the aldehydes 12a-d are not purified but submitted to a Mukaiyama-type aldol addition whereby hydroxyesters 15a-d are formed as single diastereomers in a chelate-controlled reaction. The relative configuration of the esters 15a-d is proven by conversion into the oxazolidinones 16a-d whose optical purity is determined to exceed 92% e.e. by 1H-NMR measurements in the presence of chiral shift reagents. The sulfonylimine 21a and a series of para-substituted derivatives 21b-h are also allowed to react with the vinyllithium reagent 1b to give mixtures of diastereomers 22/23. The logarithms of the diastereomeric ratios 22:23 correlate with Hammett's σ-values. VCH Verlagsgesellschaft mbH, 1997.
