17575-58-5Relevant articles and documents
Direct Deamination of Primary Amines via Isodiazene Intermediates
Berger, Kathleen J.,Driscoll, Julia L.,Yuan, Mingbin,Dherange, Balu D.,Gutierrez, Osvaldo,Levin, Mark D.
supporting information, p. 17366 - 17373 (2021/11/04)
We report here a reaction that selectively deaminates primary amines and anilines under mild conditions and with remarkable functional group tolerance including a range of pharmaceutical compounds, amino acids, amino sugars, and natural products. An anomeric amide reagent is uniquely capable of facilitating the reaction through the intermediacy of an unprecedented monosubstituted isodiazene intermediate. In addition to dramatically simplifying deamination compared to existing protocols, our approach enables strategic applications of iminium and amine-directed chemistries as traceless methods. Mechanistic and computational studies support the intermedicacy of a primary isodiazene which exhibits an unexpected divergence from previously studied secondary isodiazenes, leading to cage-escaping, free radical species that engage in a chain, hydrogen-atom transfer process involving aliphatic and diazenyl radical intermediates.
Enantioselective synthesis of nitriles containing a quaternary carbon center by michael reactions of silyl ketene imines with 1-acrylpyrazoles
Chen, Long,Pu, Maoping,Li, Shiyang,Sang, Xinpeng,Liu, Xiaohua,Wu, Yun-Dong,Feng, Xiaoming
, p. 19091 - 19098 (2021/11/22)
The enantioselective construction of quaternary carbon centers is a marked challenge in asymmetric catalysis research. It is extremely difficult when a chiral catalyst can not distinguish the facial selectivity of the substrate through bond interactions. Here we realized an enantioselective Michael reaction of silyl ketene imines to 1-acrylpyrazoles using a chiral N,N′-dioxide-Co(II) complex. The protocol is highly efficient for the construction of nitrile-, aryl-, and dialkyl-bearing carbon centers and has been successful applied in the divergent synthesis of pharmaceuticals and natural products. The through-space dispersion interactions between unbound silyl ketene imines and the 1-acrylpyrazole-bonded catalyst play a key role in facilitating the reactivity and the enantioselectivity of this process.
Regiodivergent Copper Catalyzed Borocyanation of 1,3-Dienes
Jia, Tao,He, Qiong,Ruscoe, Rebecca E.,Pulis, Alexander P.,Procter, David J.
, p. 11305 - 11309 (2018/08/28)
Copper catalyzed multi-functionalization of unsaturated carbon-carbon bonds is a powerful tool for the generation of complex molecules. We report a regiodivergent process that allows a switch between 1,4-borocupration and 4,1-borocupration of 1,3-dienes upon a simple change in ligand. The subsequently generated allyl coppers are trapped in an electrophilic cyanation to selectively generate densely functionalized and synthetically versatile 1,2- or 4,3-borocyanation products.
Tert-Butoxide-Mediated Arylation of 2-Substituted Cyanoacetates with Diaryliodonium Salts
Qian, Xiaofei,Han, Jianwei,Wang, Limin
, p. 940 - 946 (2016/04/05)
A transition metal-free direct arylation of 2-substituted cyanoacetates with diaryliodonium salts was developed. With this approach, a wide range of α-tolunitrile derivatives has been synthesized in good to excellent yields of 45-92%. Furthermore, the practicability of this approach is further manifested in the synthesis of a related bioactive agent of glutarimide.
Photochemically immobilized 4-methylbenzoyl cellulose as a powerful chiral stationary phase for enantioselective chromatography
Francotte, Eric,Huynh, Dan,Zhang, Tong
, (2016/12/30)
A process to immobilize para-methylbenzoyl cellulose (PMBC) on silica gel has been developed and applied to prepare chiral stationary phases (CSPs) for enantioselective chromatography. The immobilization was achieved by simple irradiation of the polysaccharide derivative with ultraviolet light after coating on a silica gel support. The influence of parameters such as irradiation time and solvent on immobilization effectiveness were investigated. The performance of the prepared immobilized phases were evaluated by injection of a series of racemic compounds onto the packed columns and determination of their chiral recognition ability. By contrast to the classical coated phase, the immobilized CSP can be used under various chromatographic conditions without limitation of organic solvent types as the mobile phase. This extended applicability permits to improve selectivity and to resolve chiral compounds which are not or only poorly soluble in the mobile phases which are compatible with the non-immobilized PMBC stationary phase.
Solution-phase synthesis and evaluation of tetraproline chiral stationary phases
Dai, Zhi,Ye, Guozhong,Pittman Jr., Charles U.,Li, Tingyu
experimental part, p. 329 - 338 (2012/05/20)
A protocol was developed for the solution-phase synthesis of multigram amounts of two 9-fluorenylmethoxycarbonyl (Fmoc)-protected tetraproline peptides. These tetraproline peptides were then attached to amino derivatized silica gel. The replacement of the Fmoc group with the trimethylacetyl group lead to two tetraproline chiral stationary phases (CSPs). A comparison of the chromatographic behavior of these two solution-phase-synthesized tetraproline CSPs with that prepared by stepwise solid-phase synthesis revealed that all three had similar chromatographic performance for resolving 53 model analytes. This suggests that the solution-phase synthesis of oligoprolines, which allows for the specific benefits of good batch reproducibility, selector homogeneity, and possibly low cost, is a feasible alternative to the solid-phase synthesis of oligoproline CSPs. Copyright
Synthesis of dendrimer-type chiral stationary phases based on the selector of (1S,2R)-(+)-2-amino-1,2-diphenylethanol derivate and their enantioseparation evaluation by HPLC
He, Bao-Jiang,Yin, Chuan-Qi,Li, Shi-Rong,Bai, Zheng-Wu
experimental part, p. 69 - 76 (2010/09/09)
In our recent work, a series of dendritic chiral stationary phases (CSPs) were synthesized, in which the chiral selector was L-2-(p-toluenesulfonamido)-3- phenylpropionyl chloride (selector I), and the CSP derived from three-generation dendrimer showed the best separation ability. To further investigate the influence of the structures of dendrimer and chiral selector on enantioseparation ability, in this work, another series CSPs (CSPs 1-4) were prepared by immobilizing (1S,2R)-1,2-diphenyl-2-(3-phenylureido)ethyl 4-isocyanatophenylcarbamate (selector II) on one- to four-generation dendrimers that were prepared in previous work. CSPs 1 and 4 demonstrated the equivalent enantioseparation ability. CSPs 2 and 3 showed the best and poorest enantioseparation ability respectively. Basically, these two series of CSPs exhibited the equivalent enantioseparation ability although the chiral selectors were different. Considering the enantioseparation ability of the CSP derived from aminated silica gel and selector II is much better than that of the one derived from aminated silica gel and selector I, it is believed that the dendrimer conformation essentially impacts enantioseparation.
THERMALLY IMMOBILIZED POLYSACCHARIDE DERIVATIVES
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Page 7; 11; 13, (2008/06/13)
The invention essentially relates to thermally crosslinked polysaccharide derivatives which contained no polymerizable functional groups prior to crosslinking and which are used in particular as support materials for the chromatographic separation of enantiomers. The present invention relates to thermally crosslinked polysaccharide derivatives in which the OH groups, as OR groups, have been esterified or converted into a carbamate (urethane), or mixtures of these, with the proviso that the OR groups contained no polymerizable double bonds prior to crosslinking. The thermally crosslinked polysaccharides according to the invention in conditioned form can also be used as pure polymers for the chromatographic separation of enantiomers.
Transition-metal-based Lewis acid and base ambiphilic catalysts of iridium hydride complexes: Multicomponent synthesis of glutarimides
Takaya, Hikaru,Yoshida, Kazunori,Isozaki, Katsuhiro,Terai, Hiroki,Murahashi, Shun-Ichi
, p. 3302 - 3304 (2007/10/03)
Mutual destruction of reagents in acid-and base-promoted reactions in the same container is now avoidable with the iridium polyhydride complex [IrH5(PiPr3)2] (1), which is an ambiphilic Lewis acid and base catalyst. By using catalyst 1, a three-component reaction of nitriles, olefins, and water proceeds efficiently to give glutarimides, which are pharmacologically important (see scheme).
An efficient synthesis of N-benzyl-3-sulfonyl glutarimides. Formal synthesis of the aromatase inhibitor AG-1
Chang, Meng-Yang,Chang, Bo-Rui,Tai, Huo-Mu,Chang, Nein-Chen
, p. 10273 - 10276 (2007/10/03)
A formal [3+3] cycloaddition strategy to substituted glutarimides was studied. N-Benzyl α-sulfonylacetamides and various α,β-unsaturated esters were used as starting materials. (C) 2000 Elsevier Science Ltd.
