- Photocatalyzed Triplet Sensitization of Oximes Using Visible Light Provides a Route to Nonclassical Beckmann Rearrangement Products
-
Oximes are valuable synthetic intermediates for the preparation of a variety of functional groups. To date, the stereoselective synthesis of oximes remains a major challenge, as most current synthetic methods either provide mixtures of E and Z isomers or furnish the thermodynamically preferred E isomer. Herein we report a mild and general method to achieve Z isomers of aryl oximes by photoisomerization of oximes via visible-light-mediated energy transfer (EnT) catalysis. Facile access to (Z)-oximes provides opportunities to achieve regio- and chemoselectivity complementary to those of widely used transformations employing oxime starting materials. We show an enhanced one-pot protocol for photocatalyzed oxime isomerization and subsequent Beckmann rearrangement that enables novel reactivity with alkyl groups migrating preferentially over aryl groups, reversing the regioselectivity of the traditional Beckmann reaction. Chemodivergent N- or O- cyclizations of alkenyl oximes are also demonstrated, leading to nitrones or cyclic oxime ethers, respectively.
- Zhang, Xiao,Rovis, Tomislav
-
supporting information
p. 21211 - 21217
(2021/12/27)
-
- Asymmetric Full Saturation of Vinylarenes with Cooperative Homogeneous and Heterogeneous Rhodium Catalysis
-
Homogeneous and heterogeneous catalyzed reactions can seldom operate synergistically under the same conditions. Here we communicate the use of a single rhodium precursor that acts in both the homogeneous and heterogeneous phases for the asymmetric full saturation of vinylarenes that, to date, constitute an unmet bottleneck in the field. A simple asymmetric hydrogenation of a styrenic olefin, enabled by a ligand accelerated effect, accounted for the facial selectivity in the consecutive arene hydrogenation. Tuning the ratio between the phosphine ligand and the rhodium precursor controlled the formation of homogeneous and heterogeneous catalytic species that operate without interference from each other. The system is flexible in terms of both the chiral ligand and the nature of the external olefin. We anticipate that our findings will promote the development of asymmetric arene hydrogenations.
- Andersson, Pher G.,Massaro, Luca,Peters, Bram B. C.,Wu, Haibo,Yang, Jianping,Zheng, Jia
-
supporting information
p. 20377 - 20383
(2021/12/03)
-
- Selective Dehydrogenative Acylation of Enamides with Aldehydes Leading to Valuable β-Ketoenamides
-
We have presented a unique example of dehydrogenative acylation of enamides with aldehydes enabled by an earth-abundant iron catalyst. The protocol provides the straightforward access to valuable β-ketoenamides with ample substrate scope and excellent functional group tolerance. Notably, distinct C-H acylation of enamide rather than at N-H moiety site occurs with absolute Z-selectivity was observed. Late-stage modifications of complex molecules and versatile synthetic utility of β-ketoenamides further highlight the practicability of this transformation.
- Liu, Rui-Hua,Shen, Zhen-Yao,Wang, Cong,Loh, Teck-Peng,Hu, Xu-Hong
-
supporting information
p. 944 - 949
(2020/02/15)
-
- Deconstructive Oxygenation of Unstrained Cycloalkanamines
-
A deconstructive oxygenation of unstrained primary cycloalkanamines has been developed for the first time using an auto-oxidative aromatization promoted C(sp3)?C(sp3) bond cleavage strategy. This metal-free method involves the substitution reaction of cycloalkanamines with hydrazonyl chlorides and subsequent auto-oxidative annulation to in situ generate pre-aromatics, followed by N-radical-promoted ring-opening and further oxygenation by 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) and m-cholorperoxybenzoic acid (mCPBA). Consequently, a series of 1,2,4-triazole-containing acyclic carbonyl compounds were efficiently produced. This protocol features a one-pot operation, mild reaction conditions, high regioselectivity and ring-opening efficiency, broad substrate scope, and is compatible with alkaloids, osamines, and peptides, as well as steroids.
- Han, Bing,He, Yi-Heng,Pan, Jia-Hao,Wang, Yuan-Rui,Yu, Wei,Zhang, Jian-Wu
-
supporting information
p. 3900 - 3904
(2020/02/11)
-
- Access to Cyanoimines Enabled by Dual Photoredox/Copper-Catalyzed Cyanation of O-Acyl Oximes
-
An efficient strategy for the synthesis of pharmaceutically important and synthetically useful cyanoimines, as well as cyanamides, has been described. This strategy is enabled by dual photoredox/copper-catalyzed cyanation of O-acyl oximes or O-acyl hydroxamides. This state of the art protocol for cyanoimines and cyanamides features readily available starting materials, mild reaction conditions, good functional group tolerance, and operational simplicity. The resultant cyanoimines can be transformed into structurally diverse and functionally important N-containing heterocycles.
- Wei, Ziyan,Yu, Shouyun,Zhang, Ai Hua,Zhang, Hao
-
supporting information
p. 7315 - 7320
(2020/10/02)
-
- Photochemical Flow Oximation of Alkanes
-
The nitrosation of several alkanes using tert-butyl nitrite has been performed in flow showing a remarkable reduction in the reaction time compared with batch processing. Due to the necessity for large excesses of the alkane component a continuous recycling process was devised for the preparation of larger quantities of material.
- Griffiths, Oliver M.,Ruggeri, Michele,Baxendale, Ian R.
-
supporting information
p. 1907 - 1912
(2020/10/06)
-
- Chemoenzymatic Synthesis of a Chiral Ozanimod Key Intermediate Starting from Naphthalene as Cheap Petrochemical Feedstock
-
Ozanimod represents a recently developed, promising active pharmaceutical ingredient (API) molecule in combating multiple sclerosis. Addressing the goal of a scalable, economically attractive, and technically feasible process for the manufacture of this drug, a novel alternative synthetic approach toward (S)-4-cyano-1-aminoindane as a chiral key intermediate for ozanimod has been developed. The total synthesis of this intermediate is based on the utilization of naphthalene as a readily accessible, economically attractive, and thus favorable petrochemical starting material. At first, naphthalene is transformed into 4-carboxy-indanone within a four-step process by means of an initial Birch reduction, followed by an isomerization of the C=C double bond, oxidative C=C cleavage, and intramolecular Friedel-Crafts acylation. The transformation of the 4-carboxy-indanone into (S)-4-cyano-1-aminoindane then represents the key step for introducing the chirality and the desired absolute S configuration. When evaluating complementary biocatalytic approaches based on the use of a lipase and transaminase, respectively, the combination of a chemical reductive amination of the 4-carboxyindanone followed by a subsequent lipase-catalyzed resolution turned out to be the most efficient route, leading to the desired key intermediate (S)-4-cyano-1-aminoindane in satisfactory yield and with excellent enantiomeric excess of 99%.
- Uthoff, Florian,L?we, Jana,Harms, Christina,Donsbach, Kai,Gr?ger, Harald
-
p. 4856 - 4866
(2019/05/02)
-
- Enantioselective Hydrogenation of Activated Aryl Imines Catalyzed by an Iron(II) P-NH-P′ Complex
-
Chiral amines are key building blocks in synthetic chemistry with numerous applications in the agricultural and pharmaceutical industries. Asymmetric imine hydrogenation, particularly with iridium catalysts, is well developed. However, imine reduction still remains challenging in the context of replacing such a precious metal with a cheap, nontoxic, and environmentally friendly substitute such as iron. Here, we report that an unsymmetrical iron P-NH-P′ catalyst that was previously shown to be effective for the asymmetric hydrogenation of aryl ketones is also a very effective catalyst for the asymmetric hydrogenation of prochiral aryl imines activated with N-diphenylphosphinoyl or N-tosyl groups. The P-NH-P′ abbreviation stands for (S,S)-PPh2CHPhCHPhNHCH2CH2PiPr2. Density functional theory results suggest that, surprisingly, the NH group on the catalyst activates and orients the imine to hydride attack by hydrogen bonding to the PO or SO group on the imine nitrogen, as opposed to the imine nitrogen itself. This may explain why N-Ph and N-Bu imines are not hydrogenated.
- Seo, Chris S. G.,Tannoux, Thibault,Smith, Samantha A. M.,Lough, Alan J.,Morris, Robert H.
-
p. 12040 - 12049
(2019/10/02)
-
- PRODUCTION METHOD OF KETOXIME COMPOUND
-
PROBLEM TO BE SOLVED: To provide a new catalytic production method of a ketoxime that does not directly use hydroxyamine, nor require severe reaction conditions. SOLUTION: A production method of a ketoxime compound includes a step for transoximizing a ketone compound and ethyl acetohydroxamate in the presence of an organic solvent and a trifluoromethanesulfonic acid metal salt. The trifluoromethanesulfonic acid metal salt is preferably scandium (III) trifluoromethanesulfonate. The organic solvent is preferably methylene chloride, methanol, ethanol, n-propanol, or n-butanol. SELECTED DRAWING: None COPYRIGHT: (C)2017,JPOandINPIT
- -
-
Paragraph 0022-0024
(2017/10/11)
-
- PROCESS AND INTERMEDIATES FOR THE RACEMIZATION OF ENANTIOMERICALLY ENRICHED 1-AMINOINDANE
-
The present invention relates to an improved process for the racemization of (S) -1-aminoindane. (S) -1-aminoindane is formed as a side product in the process of preparation (R) -1-aminoindane by enantiomeric resolution of racemic 1-aminoindane. (R) -aminoindane is a valuable intermediate in the process of preparation of rasagiline.
- -
-
Page/Page column 22-23
(2016/08/17)
-
- Highly enantioselective [3+2] coupling of cyclic enamides with quinone monoimines promoted by a chiral phosphoric acid
-
Enantioselective [3+2] coupling of cyclic enamides with quinone monoimines was realised using a chiral phosphoric acid as a catalyst. This transformation allowed for the synthesis of highly enantioenriched polycyclic 2,3-dihydrobenzofurans (up to 99.9% ee). The absolute configuration of one product was determined by an X-ray crystal structural analysis. We also found a possible mechanism for this reaction.
- Zhang, Minmin,Yu, Shuowen,Hu, Fangzhi,Liao, Yijun,Liao, Lihua,Xu, Xiaoying,Yuan, Weicheng,Zhang, Xiaomei
-
supporting information
p. 8757 - 8760
(2016/07/15)
-
- Enantioselective Hydrosilylation of Imines Catalyzed by Chiral Zinc Acetate Complexes
-
A series of zinc acetate complexes with optically pure diphenylethanediamine (DPEDA)-derived ligands have been employed as enantioselective catalyst for the hydrosilylation of various imines. High control of stereoselectivity (up to 97% ee) and excellent yields (up to 96%) were gained for a broad range of N-phosphinoylimines by using (R,R)-N,N′-dibenzyl-1,2-diphenylethane-1,2-diamine. This is the first successful application of an air-stable and environmentally friendly chiral Zn(OAc)2 complex instead of the previously used harmful diethylzinc in the asymmetric reduction of the C=N double bond.
- Bez?ada, Agata,Szewczyk, Marcin,Mlynarski, Jacek
-
p. 336 - 342
(2016/01/15)
-
- TRICYCLIC GUANIDINE DERIVATIVE
-
Disclosed are compounds useful as inhibitors of Phosphodiesterase 1 (PDE1), compositions thereof, and methods of using the same.
- -
-
Paragraph 0228; 0230
(2016/04/19)
-
- TETRAZOLINONE COMPOUND AND USE THEREOF
-
The compound represented by formula (1): wherein R4 and R5 each represents a hydrogen atom, a halogen atom, or a C1-C3 alkyl group; R6 represents a C1-C4 alkyl group, a C3-C6 cycloalkyl group, or the like; R7, R8, and R9 each represents a hydrogen atom, a halogen atom, or the like; R10 represents a C1-C3 alkyl group, or the like; R13 represents a C1-C3 alkyl group, or the like; and Q represents a phenyl group, or the like; has an excellent control effect on pests.
- -
-
Paragraph 0844-0845
(2015/11/16)
-
- PROCESS FOR THE PREPARATION OF ENATIOMERICALLY PURE 1-AMINOINDAN
-
The present invention relates to a process for the preparation of optically pure ( R) -1-aminoindan by a diastereomeric resolution of 1-aminoindan using N-acetyl-L-glutamic acid as a resolving agent. In another aspect, the invention relates to diastereomeric salts of (R) -1-aminoindan with N-acetyl-L-glutamic acid, and their use in the process for the preparation of rasagiline.
- -
-
Page/Page column 17
(2015/06/03)
-
- Synthesis of Air- and Moisture-Stable, Storable Chiral Oxorhenium Complexes and Their Application as Catalysts for the Enantioselective Imine Reduction
-
Air-/moisture-stable, crystalline, and storable chiral salicyloxazoline based oxorhenium(V) complexes have been synthesized and their catalytic application for the asymmetric reduction of ketimines using hydrosilane as hydride source is disclosed. A broad substrate scope, high yields, and excellent enantioselectivities (up to 99 %) are attained. Furthermore, the syntheses of enantiopure α-amino esters, γ- and δ-lactams, and isoindolinones have also been carried out using this methodology. Finally, the method has been applied to synthetic targets of pharmaceutical relevance, such as R-(+)-salsolidine and R-(+)-crispine A.
- Das, Braja Gopal,Nallagonda, Rajender,Dey, Dhananjay,Ghorai, Prasanta
-
supporting information
p. 12601 - 12605
(2015/09/01)
-
- A novel synthesis of rasagiline via a chemoenzymatic dynamic kinetic resolution
-
A novel synthetic route for preparing rasagiline mesylate is presented using a dynamic kinetic resolution (DKR) as the key step, catalyzed by Candida antarctica lipase B (CALB) and a Pd nanocatalyst. The chiral intermediate (R)-2,3-dihydro-1-indanamine was obtained through the DKR of the racemic aminoindan rac-1 in high yield (>90%) and excellent enantioselectivity (>99% ee). The process could be conducted on a 73 g scale at 200 g/L. Rasagiline mesylate was synthesized in 25% overall yield and excellent enantioselectivity (99.9% ee) over 7 steps.
- Ma, Guozhen,Xu, Zhongqi,Zhang, Pengfei,Liu, Jinpo,Hao, Xilin,Ouyang, Jingping,Liang, Ping,You, Song,Jia, Xian
-
p. 1169 - 1174
(2014/12/10)
-
- Rhodium(iii)-catalyzed olefinic C-H alkynylation of enamides at room temperature
-
Rh(iii)-catalyzed C-H olefinic alkynylation of enamides for the stereospecific construction of synthetically useful Z-type enynamides is reported. This protocol displays good functionality tolerance and operational simplicity thus providing an alternative synthetic opportunity for the ease of access to specific 1,3-enyne derivatives.
- Feng, Chao,Feng, Daming,Loh, Teck-Peng
-
supporting information
p. 9865 - 9868
(2014/08/18)
-
- Oxidation of primary amines to oximes with molecular oxygen using 1,1-diphenyl-2-picrylhydrazyl and WO3/Al2O3 as catalysts
-
The oxidative transformation of primary amines to their corresponding oximes proceeds with high efficiency under molecular oxygen diluted with molecular nitrogen (O2/N2 = 7/93 v/v, 5 MPa) in the presence of the catalysts 1,1-diphenyl-2-picrylhydrazyl (DPPH) and tungusten oxide/alumina (WO3/Al2O3). The method is environmentally benign, because the reaction requires only molecular oxygen as the terminal oxidant and gives water as a side product. Various alicyclic amines and aliphatic amines can be converted to their corresponding oximes in excellent yields. It is noteworthy that the oxidative transformation of primary amines proceeds chemoselectively in the presence of other functional groups. The key step of the present oxidation is a fast electron transfer from the primary amine to DPPH followed by proton transfer to give the α-aminoalkyl radical intermediate, which undergoes reaction with molecular oxygen and hydrogen abstraction to give α-aminoalkyl hydroperoxide. Subsequent reaction of the peroxide with WO3/Al2O3 gives oximes. The aerobic oxidation of secondary amines gives the corresponding nitrones. Aerobic oxidative transformation of cyclohexylamines to cyclohexanone oximes is important as a method for industrial production of ε-caprolactam, a raw material for Nylon 6.
- Suzuki, Ken,Watanabe, Tomonari,Murahashi, Shun-Ichi
-
p. 2301 - 2310
(2013/04/24)
-
- Asymmetric transfer hydrogenation of ketimines using well-defined iron(II)-based precatalysts containing a PNNP ligand
-
Well-defined iron(II)-based complexes containing PNNP ligands catalyze a highly enantioselective reduction of N-(diphenylphosphinoyl)- and N-(p-tolylsulphonyl)-ketimines. Under mild conditions and low catalyst loading, the ketimines are successfully reduced to the corresponding amines in enantiomeric excess ranging from 94 to 99%.
- Mikhailine, Alexandre A.,Maishan, Mazharul I.,Morris, Robert H.
-
supporting information
p. 4638 - 4641
(2012/10/29)
-
- RASAGILINE AND ITS PHARMACEUTICALLY ACCEPTABLE SALTS
-
The present invention relates to Rasagiline acid addition salts having a particle size D(90) greater than 250 microns and D(50) greater than 100 microns, with the proviso that acid addition salt is not mesylate. The invention also discloses a process for the preparation of such Rasagiline acid addition salts.
- -
-
Page/Page column 29
(2012/12/13)
-
- Enantioselective reduction of ketoxime ethers with borane-oxazaborolidines and synthesis of the key intermediate leading to (S)-rivastigmine
-
The reduction of representative alkyl aryl (E)-ketoxime O-benzyl ethers with borane catalyzed by terpene oxazaborolidines, derived from (1R)-nopinone and (1R)-camphor, gave the corresponding amines with 82-99% ee. Oxazaborolidines derived from (1S)-2-carene and (1S)-3-carene were less selective. (S)-1-(3-Methoxyphenyl)ethanamine (94% ee) the key intermediate in the synthesis of (S)-rivastigmine, was obtained by the reduction of (E)-1-(3-methoxyphenyl) ethanone O-benzyl oxime with borane/oxazaborolidine generated from (S)-valinol.
- Pakulski, Marcin M.,Mahato, Sanjit K.,Bosiak, Mariusz J.,Krzeminski, Marek P.,Zaidlewicz, Marek
-
experimental part
p. 716 - 721
(2012/09/21)
-
- Ruthenium-catalyzed hydrovinylation of N-acetylenamines leading to amines with a quaternary carbon center
-
A catalytic hydrovinylation of N-acetylenamines with ethylene is reported. This new hydrovinylation reaction is catalyzed by a ruthenium hydride complex, RuHCl(CO)(PCy3)2, providing a series of N-acetylamines with a quaternary carbon center with up to 99% yield.
- Wang, Qiu-Shi,Xie, Jian-Hua,Li, Wei,Zhu, Shou-Fei,Wang, Li-Xin,Zhou, Qi-Lin
-
supporting information; scheme or table
p. 3388 - 3391
(2011/08/21)
-
- Regioselective synthesis of heterocycles containing nitrogen neighboring an aromatic ring by reductive ring expansion using diisobutylaluminum hydride and studies on the reaction mechanism
-
(Chemical Equation Presented) A systematic investigation of the reductive ring-expansion reaction of cyclic ketoximes fused to aromatic ringswith diisobutylaluminum hydride (DIBALH) is described. This reaction regioselectively afforded a variety of five- to eight-membered bicyclic heterocycles or tricyclic heterocycles containing nitrogen neighboring an aromatic ring, including indoline, 1,2,3,4,5,6-hexahydrobenz[b]azocine, 3,4-dihydro-2H-benzo[b] [1,4]oxazine, 2,3,4,5-tetrahydrobenzo[b][1,4]thiazepine, 1,2,3,4,5,6- hexahydroazepino[3,2-b]-indole, 2,3,4,5-tetrahydro-1H-benzothieno[2,3-b]azepine, 2,3,4,5-tetrahydro-1H-benzothieno[3,2-b]-azepine, 5,6-dihydrophenanthridine, and 5,6,11,12-tetrahydrodibenz[b, f]azocine. The reaction mechanism leading to the rearrangement was investigated on the basis of the restricted Becke three-parameter plus Lee-Yang-Parr (B3LYP) density functional theory (DFT) with the 6-31G (d) basis set. It was found that the reaction proceeds through a three-centered transition state via a stepwise mechanism because the potential energy curve along the intrinsic reaction coordinate (IRC) had twomaxima (saddle points; TS1 and TS2) and the partial phenonium cation intermediate C. In addition to cyclic ketoximes fused to aromatic rings, the reactions of various cyclic and acyclic ketoximeswere examined to investigate preference of migrating group. It was found that themore electron-rich group migrated preferentially to give the corresponding secondary amines.
- Cho, Hidetsura,Iwama, Yusuke,Sugimoto, Kenji,Mori, Seiji,Tokuyama, Hidetoshi
-
experimental part
p. 627 - 636
(2010/04/29)
-
- Synthesis, 3D-QSAR, and structural modeling of benzolactam derivatives with binding affinity for the D2and D3 receptors
-
A series of 37 benzolactam derivatives were synthesized, and their respective affinities for the dopamine D2 and D3 receptors evaluated. The relationships between structures and binding affinities were investigated using both ligand-based (3D-QSAR) and receptor-based methods. The results revealed the importance of diverse structural features in explaining the differences in the observed affinities, such as the location of the benzolactam carbonyl oxygen, or the overall length of the compounds. The optimal values for such ligand properties are slightly different for the D2 and D 3 receptors, even though the binding sites present a very high degree of homology. We explain these differences by the presence of a hydrogen bond network in the D2 receptor which is absent in the D3 receptor and limits the dimensions of the binding pocket, causing residues in helix 7 to become less accessible. The implications of these results for the design of more potent and selective benzolactam derivatives are presented and discussed.
- Lopez, Laura,Selent, Jana,Ortega, Raquel,Masaguer, Christian F.,Dominguez, Eduardo,Areias, Filipe,Brea, Jose,Loza, Maria Isabel,Sanz, Ferran,Pastor, Manuel
-
experimental part
p. 1300 - 1317
(2011/01/04)
-
- PREPARATION OF CHIRAL AMIDES AND AMINES
-
This invention provides a convenient method for converting oximes into enamides. The process does not require the use of metallic reagents. Accordingly, it produces the desired compounds without the concomitant production of a large volume of metallic waste. The enamides are useful precursors to amides and amines. The invention provides a process to convert a prochiral enamide into the corresponding chiral amide. In an exemplary process, a chiral amino center is introduced during hydrogenation through the use of a chiral hydrogenation catalyst. In selected embodiments, the invention provides methods of preparing amides and amines that include the 1,2,3,4-tetrahydro-N-alkyl-1-naphthalenamine or 1,2,3,4-tetrahydro-1-naphthalenamine substructure.
- -
-
Page/Page column 22
(2009/06/27)
-
- A facile and practical synthesis of N-acetyl enamides
-
(Chemical Equation Presented) A facile and practical method for the synthesis of N-acetyl α-arylenamides has been developed from corresponding ketoximes as the starting materials with ferrous acetate as the reducing reagent. This methodology offers mild reaction conditions, simple purification procedures, and high yields for a variety of N-acetyl enamides.
- Tang, Wenjun,Capacci, Andrew,Sarvestani, Max,Wei, Xudong,Yee, Nathan K.,Senanayake, Chris H.
-
supporting information; body text
p. 9528 - 9530
(2010/03/24)
-
- Regiospecific synthesis of unsubstituted basic skeletons of heterocycles containing nitrogen neighboring an aromatic ring by the reductive ring expansion reaction using diisobutylaluminum hydride
-
A systematic investigation of reductive ring expansion reaction of oximes with diisobutylaluminum hydride (DIBAH) was performed. The reaction regiospecifically provided a variety of unsubstituted bicyclic heterocycles 3a-3g or tricyclic heterocycles 3h, 3j-3l that contained nitrogen attached to an aromatic ring.
- Cho, Hidetsura,Iwama, Yusuke,Sugimoto, Kenji,Kwon, Eunsang,Tokuyama, Hidetoshi
-
experimental part
p. 1183 - 1190
(2009/11/30)
-
- Facile and efficient enantioselective strecker reaction of ketimines by chiral sodium phosphate
-
A facile and efficient enantioselective Strecker reaction of ketimines catalyzed by a chiral alkali-metal salt has been developed. When 10 mol% BNPNa (BNP=1,1'-binaphthyl-2,2'-diylphosphate) prepared in situ and 10 mol% para-tert-butylortho-adamantylphenol (PBAP) were introduced into the reaction, up to 96% yield and up to 95% ee (ee=enantiomeric excess) were obtained. Both aliphatic and aromatic ketimines, especially sterically bulky cyclic ketimines derived from β-acetonaphthone, α-indanone, and α-tetralone were found suitable for this reaction. On the basis of the experimental results and previous reports, trimethylsilyl cyanide (TMSCN) was indicated to be the real reactive nucleophile despite the existence of PBAP, and a possible working model was proposed to explain the origin of the asymmetric induction. The facile availability of 1,1'-binaphthyl-2,2'-diylphosphoric acid (BNPH) and the simplicity of the procedure are beneficial for practical applications.
- Shen, Ke,Liu, Xiaohua,Cai, Yunfei,Lin, Lili,Feng, Xiaoming
-
supporting information; experimental part
p. 6008 - 6014
(2010/02/28)
-
- Aerobic oxidation of primary amines to oximes catalyzed by DPPH and WO 3/Al2O3
-
(Chemical Equation Presented) Catalytic teamwork: Aerobic oxidation of primary amines to the corresponding oximes proceeds highly efficiently in the presence of the catalysts 1,1-diphenyl-2-picrylhydrazyl (DPPH) and WO 3/Al2O3 under mild conditions (see scheme). This new method is both selective and environmentally benign.
- Suzuki, Ken,Watanabe, Tomonari,Murahashi, Shun-Ichi
-
supporting information; experimental part
p. 2079 - 2081
(2009/02/06)
-
- Enantioselective Strecker reaction of phosphinoyl ketoimines catalyzed by in situ prepared chiral N,N′-dioxides
-
The enantioselective Strecker reaction of N-diphenylphosphinoyl ketoimines has been achieved by use of in situ prepared chiral N,N′-dioxide catalyst from L-piperidinamide 3f and m-chloroperoxybenzoic acid (m-CPBA). Excellent yields (up to 99%) and high enantioselectivities (up to 92% ee) were obtained. In particular, in situ prepared catalyst with readily available chiral material made the procedure more convenient. Moreover, the L-piperidinamide 3f-derived N,N′-dioxide 9 could be recycled and reused at least five times without any loss of either catalytic activity or enantioselectivity.
- Huang, Jinglun,Liu, Xiaohua,Wen, Yuehong,Qin, Bo,Feng, Xiaoming
-
p. 204 - 208
(2007/10/03)
-
- Carbocyclization by radical closure onto O-trityl oximes: Dramatic effect of diphenyl diselenide
-
O-Trityl oximes of 5- and 6-iodoaldehydes undergo radical cyclization to produce oximes when treated in refluxing tetrahydrofuran (THF) with Bu 3SnH, 1,1′-azobis(cyclohexanecarbonitrile), i-Pr 2NEt, and diphenyl diselenide (PhSeSePh).
- Clive, Derrick L. J.,Pham, Mai P.,Subedi, Rajendra
-
p. 2713 - 2717
(2007/10/03)
-
- Thermal decomposition of O-benzyl ketoximes; role of reverse radical disproportionation
-
Thermolyses of seven dialkyl, two alkyl-aryl and two diaryl O-benzyl ketoxime ethers, R1R2C=NOCH2Ph, have been examined in three hydrogen donor solvents: tetralin, 9,10-dihydrophenanthrene, and 9,10-dihydroanthracene. All the oxime ethers gave the products expected from homolytic scission of both the O-C bond (viz., R1R2C=NOH and PhCH3) and N-O bond (viz., R1R2C=NH and PhCH2OH). The yields of these products depended on which solvent was used and the rates of decomposition of the O-benzyl oxime ethers were greater in 9,10-dihydrophenanthrene and 9,10-dihydroanthracene than in tetralin. These results indicated that a reverse radical disproportionation reaction in which a hydrogen atom was transferred from the solvent to the oxime ether, followed by β-scission of the resultant aminoalkyl radical, must be important in the latter two solvents. Benzaldehyde was found to be an additional product from thermolyses conducted in tetralin. This, and other evidence, indicated that another induced decomposition mode involving abstraction of a benzylic hydrogen atom, followed by β-scission of the resulting benzyl radical, became important for some substrates. Participation by minor amounts of enamine tautomers of the oxime ethers was shown to be negligible by comparison of thermolysis data for the O-benzyloxime of bicyclo[3.3.1]nonan-9-one, which cannot give an enamine tautomer, with that of the O-benzyloxime of cyclohexanone.
- Blake, Jessie A.,Ingold, Keith U.,Lin, Shuqiong,Mulder, Peter,Pratt, Derek A.,Sheeller, Brad,Walton, John C.
-
p. 415 - 420
(2007/10/03)
-
- A preparative route to fused indeno[1,2-e][1,2,4]-triazolo[4,3- a]pyrazin-4-ones
-
Syntheses of new fused indeno[1,2-e][1,2,4]triazolo[4,3-a]pyrazin-4-one derivatives (1a-g) starting from 1-indanone are described.
- Ribeill, Yves,Genevois-Borella, Arielle,Vuilhorgne, Marc,Mignani, Serge
-
p. 2977 - 2982
(2007/10/03)
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- 5H-INDENO[1,2-B]PYRAZINE-2,3-DIONE DERIVATIVES, THEIR PREPARATION AND MEDICINAL PRODUCTS CONTAINING THEM
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Compounds of formula (I): STR1 wherein R represents a CR. sub.4 R. sub.5, CHR 6, or C=R 7 radical and R 3 represents an oxygen atom, salts thereof, the preparation thereof and drugs containing same. The compounds of formula (I) have valuable pharmacological properties and are alpha-amino-3-hydroxy-5-methyl-4-osoxaziepropionic acid (AMPA) receptor antagonists, said receptor also being known as the quisqualate receptor. Furthermore, the compounds of formula (I) are non-competitive N-methyl-D-aspartate (NMDA) receptor antagonists, and particularly NMDA receptor glycine modulation site ligands.
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- Indane dimerization products obtained by treatment of N-acylindan-1-amines with ethyl polyphosphate (EPP)
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This report describes the diverse dimeric products obtained by treatment of N-acylindan-1-amines with ethyl polyphosphate in chloroform-diethyl ether solution at 80°C for 8 h. Possible mechanisms for such reactions are discussed.
- Moglioni, Albertina G.,Tombari, Dora G.,Moltrasio Iglesias, Graciela Y.
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p. 3459 - 3462
(2007/10/03)
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- Amberlyst A-21 an excellent heterogeneous catalyst for the conversion of carbonyl compounds to oximes
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Oximes can be efficiently obtained at room temperature by simply dissolving the appropriate carbonyl compounds and hydroxylamine hydrochloride, in ethanol, with Amberlyst A-21 as catalyst. Good yields of oximes are obtained, in very short reaction times, even with polifunctionalized substrates.
- Ballini, Roberto,Barboni, Luciano,Filippone, Paolino
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p. 475 - 476
(2007/10/03)
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- ANTIINFLAMMATORY HYDROXAMIC ACIDS AND N-HYDROXYUREAS
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Compounds having the structure wherein X is nitrogen, oxygen, sulfur or a bond and Z is oxygen or sulfur have been synthesized. These compounds are lipoxygenase inhibitors and are useful as the active agent in pharmaceutical compositions for treating inflammatory conditions in humans and other mammals for which lipoxygenase activity has been implicated.
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- Process for the resolution of 1-aminoindanes
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An improved process for the resolution of 1-aminoindanes into the R-isomer on a large scale is described. The resolving agent used in the process is R-N-acetyl-3,4-dimethoxyphenylalanine. The process is of intermediates in the production of certain adenosines and their pharmaceutically acceptable acid addition salts. The adenosines have desirable central nervous system and cardiovascular activities such as antipsychotic, sedative, antihypertensive, and antianginal.
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- A High-Yield Regiospecific Synthesis of Keto Oximes from Aryl-Conjugated Ethylenes and Ethyl Nitrite in the Presence of Cobalt Complex and BH4- Ion
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The title reaction of substituted styrenes, 1-phenyl-1,3-butadiene, and some cyclic aryl-conjugated ethylenes proceeds smoothly at room temperature, affording the corresponding oximes in moderate to nearly quantitative yields.The reaction mechanism is discussed on the basis of the formation of an alkylcobalt intermediate and its subsequent reaction with ethyl nitrite.
- Okamoto, Tadashi,Kobayashi, Kenji,Oka, Shinzaburo,Tanimoto, Shigeo
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p. 4897 - 4901
(2007/10/02)
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- Antiinflammatory, analgesic, or anti-primary dysmenorrheal arylmethylene- and arylmethylindenoimidazoles
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Antiinflammatory, analgesic and prostaglandin synthetase inhibitory arylmethylene- and arylmethylindenoimidazoles useful for the treatment of pain, inflammation, and primary dysmenorrhea having the structure STR1
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