- Asymmetric synthesis of tetrahydroisoquinoline derivatives through 1, 3-dipolar cycloaddition of C, N-cyclic azomethine imines with allyl alkyl ketones
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[3 + 2] A 1, 3-Dipolar cycloaddition of C, N-cyclic azomethine imines with allyl alkyl ketones has been achieved. The reaction proceeds under mild conditions and tolerates a wide range of functional groups. An array of tetrahydroisoquinoline derivatives is generally constructed with good diastereoselectivities and enantioselectivities (up to >25:1 dr, >95% ee). Moreover, the absolute configuration of the product was previously determined by using the quantum electronic circular dichroism calculation and ECD spectrum method.
- Chen, Wenyan,Feng, Guipeng,Ma, Guoyang,Wang, Kaikai,Wang, Shaoyan,Xu, Shaohong
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Read Online
- Dihydroisoquinolinium salts: Catalysts for asymmetric epoxidation
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A range of dihydroisoquinolinium salts were prepared and tested as asymmetric epoxidation catalysts. The factors affecting enantioselectivity of catalytic asymmetric epoxidation process were also discussed. The asymmetric epoxidation reaction employed alkaline hydrogen peroxide and a chiral polypeptide derived from a naturally occurring amino acid, leucine.
- Page, Philip C. Bulman,Rassias, Gerasimos A.,Barros, David,Bethell, Donald,Schilling, Mark B.
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Read Online
- Studies on Cu-catalyzed asymmetric alkynylation of tetrahydroisoquinoline derivatives
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Enantioselective C-C bond formations between the sp3 C-H bond of prochiral CH2 and terminal alkynes via the cross-dehydrogenative coupling (CDC) reaction were studied. Efficient asymmetric syntheses of alkynyl tetrahydroisoquinoline derivatives were achieved by using a catalytic amount of CuOTf together with PyBox chiral ligand. When dihydroisoquinolinium salts were used as electrophiles, the combination of CuBr/QUINAP provided the best results for asymmetric syntheses of alkynyl tetrahydroisoquinoline derivatives. The factors influencing the enantioselectivity were studied.
- Li, Zhiping,MacLeod, Patricia D.,Li, Chao-Jun
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Read Online
- Ytterbium-Catalyzed Intramolecular [3 + 2] Cycloaddition based on Furan Dearomatization to Construct Fused Triazoles
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The 1,2,3-triazole-containing polycyclic architecture widely exists in a broad spectrum of synthetic bioactive molecules, and the development of expeditious methods to synthesize these skeletons remains a challenging task. In this work, the catalytic cyclization of biomass-derived 2-furylcarbinols with an azide to form fused triazoles is described. This approach takes advantage of a single catalyst Yb(OTf)3 and operates via a furfuryl-cation-induced intramolecular [3 + 2] cycloaddition/furan ring-opening cascade.
- Xu, Xiaoming,Zhong, Ying,Xing, Qingzhao,Gao, Ziwei,Gou, Jing,Yu, Binxun
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p. 5176 - 5181
(2020/07/14)
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- Hydrogen-Bonding-Promoted Cascade Rearrangement Involving the Enlargement of Two Rings: Efficient Access to Polycyclic Quinoline Derivatives
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An efficient cascade reaction of tryptamine-derived isocyanides with C,N-cyclic azomethine imines is described. The polycyclic pyrrolo[2,3-c]quinoline derivatives, which benefited from rearrangement process driven by hydrogen bonding, could be directly assembled in moderate to good yields (40–87 %) under metal-free and mild conditions. This transformation involved four new heterocyclic rings formations and uniquely, ring opening of indole as well as ring expansion of C,N-cyclic azomethine imine. Both experimental and DFT studies provided guidance on the in-depth insight into the reaction pathways and hydrogen bonding was identified to lower the free energy barrier in transition states. This work constitutes a rare example of tryptamine-derived isocyanide-based cascade reactions, and potentially could be a powerful synthetic strategy for accessing polycyclic analogues involved in natural products.
- Cao, Wen-Bin,Ji, Shun-Jun,Lan, Yu,Li, Haiyan,Li, Shijun,Xu, Meng-Meng,Xu, Xiao-Ping
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supporting information
p. 21425 - 21430
(2020/09/23)
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- Enantioselective synthesis of tetrahydroisoquinoline derivatives via chiral-at-metal rhodium complex catalyzed [3+2] cycloaddition
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An asymmetric [3+2] cycloaddition of C,N-cyclic azomethine imines with α,β-unsaturated 2-acyl imidazoles catalyzed by a chiral-at-metal rhodium complex has been developed. The corresponding C-1-substituted tetrahydroisoquinoline derivatives were obtained in high yields (>90%) with excellent stereoselectivities (up to 99% ee and >20?:?1 dr). The reaction can be conducted on a gram-scale using a low catalyst loading (0.5 mol%) with high yield and selectivity.
- Qurban, Saira,Du, Yu,Gong, Jun,Lin, Shao-Xia,Kang, Qiang
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p. 249 - 252
(2019/01/04)
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- A rhodium-catalysed three-component reaction to access C1-substituted tetrahydroisoquinolines
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A rhodium-catalyzed three-component reaction of diazo compounds, anilines and C,N-cyclic azomethine imines via trapping of transient ammonium ylides was developed. This reaction provided a simple and convenient approach for the synthesis of pharmaceutically intriguing tetrahydroisoquinoline derivatives in moderate to good yields (36-85%) with good diastereoselectivities (up to 95 : 5 dr) under mild reaction conditions.
- Zhang, Dan,Liu, Junwen,Kang, Zhenghui,Qiu, Huang,Hu, Wenhao
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p. 9844 - 9848
(2019/12/05)
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- An Intramolecular Cycloaddition Approach to the Kauranoid Family of Diterpene Metabolites
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Synthetic studies toward the ent-kauranoid family of diterpene natural products are reported. An intramolecular (4 + 3) cycloaddition allows the direct elaboration of diverse natural product frameworks, encompassing a challenging bicyclo[3.2.1]octane core. The established routes comprise only a few synthetic operations (3-5 steps), transforming a range of simple starting materials into the tetracyclic scaffolds that are commonly found in many ent-kaurene metabolites.
- Callebaut, Brenda,Hullaert, Jan,Van Hecke, Kristof,Winne, Johan M.
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supporting information
p. 310 - 314
(2019/01/10)
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- USE OF DIHYDROISOQUINOLINIUM SALTS FOR TREATING KERATIN MATERIALS, COMPOSITIONS AND IMPLEMENTATION PROCESSES
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Use of dihydroisoquinolinium salts for treating keratin materials, compositions and implementation processes The present invention relates to the use of one or more dihydroisoquinolinium salts for treating keratin materials, in particular keratin fibres, especially human keratin fibres such as the hair. The invention also relates to a process for treating keratin materials using said salts and optionally in the presence of one or more chemical oxidizing agents. A subjectof the invention is also a composition for lightening keratin materials, comprising one or more dihydroisoquinolinium salts as defined below and one or more chemical oxidizing agents.
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Page/Page column 31
(2017/07/14)
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- Reactions Catalysed by a Binuclear Copper Complex: Relay Aerobic Oxidation of N-Aryl Tetrahydroisoquinolines to Dihydroisoquinolones with a Vitamin B1 Analogue
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N-Aryl tetrahydroisoquinolines were oxidised to dihydroisoquinolones through the relay catalysis of a binuclear paddle-wheel copper complex and a vitamin B1 analogue with oxygen as oxidant. Mechanistic studies revealed that the copper catalyst oxidises amines to the corresponding iminium salts, which are then oxygenated to lactam products by catalysis of the vitamin B1 analogue.
- Liu, Yuxia,Wang, Chao,Xue, Dong,Xiao, Miao,Liu, Jiao,Li, Chaoqun,Xiao, Jianliang
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supporting information
p. 3062 - 3066
(2017/03/13)
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- Phosphane-Catalyzed [3+3] Annulation of C,N-Cyclic Azomethine Imines with Ynones: A Practical Method for Tricyclic Dinitrogen-Fused Heterocycles
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A phosphane-catalyzed [3+3] annulation of azomethine imines with ynones has been developed. Under mild reaction conditions, the reaction proceeds smoothly to afford tricyclic dinitrogen-fused heterocyclic compounds in moderate to excellent yields with moderate to excellent stereoselectivies. Using a chiral phosphine as the catalyst, the reaction could work to give the cycloadduct in moderate yield with moderate enantioselectivity. (Figure presented.) .
- Li, Zhen,Yu, Hao,Liu, Yang,Zhou, Leijie,Sun, Zhanhu,Guo, Hongchao
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p. 1880 - 1885
(2016/07/06)
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- Scaffold Diversity through a Branching Double-Annulation Cascade Strategy: Iminium-Induced One-Pot Synthesis of Diverse Fused Tetrahydroisoquinoline Scaffolds
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A branching double-annulation cascade (BDAC) strategy for diverse and complex fused THIQ scaffolds via a highly reactive iminium-induced one-pot double-cyclization sequence involving Pictect-Spengler-type cyclization has been developed for the first time. The salient features of this protocol are that it allows direct and rapid access to unprecedented diverse fused THIQ skeletons, is metal/catalyst free, has a cleaner reaction profile, provides good to excellent yields, and is a convenient approach. This catalyst-free domino process facilitates the double annulation with a variety of scaffold building agents via two C-N and one C-X (X = C, N, O) bond formation in a single step under uniform reaction conditions. Furthermore, we reveal an unusual dual BDAC sequence leading to N-N-linked isoquinoline dimer.
- Sharada, Duddu S.,Shinde, Anand H.,Patel, Srilaxmi M.,Vidyacharan, Shinde
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p. 6463 - 6471
(2016/08/16)
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- A metal-free cyclic iminium induced one-pot double annulation cascade: Access to dihydroisoquinolinium (DHIQ) salts
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A reactive cyclic iminium induced one-pot Groebke-Blackburn-Bienayme (GBB) double annulation cascade (DAC) for the synthesis of skeletally diverse DHIQ salts has been described. The key features of this protocol are transition-metal and solvent-free, mild reaction conditions, robust method, one-step construction of two privileged heterocyclic rings, clean reaction profile and operational simplicity.
- Sagar,Nagarjuna Babu, Venkata,Shinde, Anand H.,Sharada, Duddu S.
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p. 10366 - 10370
(2016/11/18)
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- Synthesis of 5,6-Dihydropyrazolo[5,1-a]isoquinoline and Ethyl (Z)-3-Acetoxy-3-tosylpent-4-enoate through Tertiary-Amine-Catalyzed [3+2] Annulation
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The 1,4-diazabicyclo[2.2.2]octane (DABCO) catalyzed divergent [3+2] annulation of C,N-cyclic azomethine imines with δ-acetoxyallenoates was developed; 5,6-dihydropyrazolo[5,1-a]isoquinolines and ethyl (Z)-3-acetoxy-3-tosylpent-4-enoates were afforded in moderate to good yields in a one-pot manner under mild conditions. This annulation reaction provides a highly efficient method to construct dinitrogen-fused heterocycles and ethyl (Z)-3-acetoxy-3-tosylpent-4-enoates at the same time.
- Lei, Yu,Xing, Jiao-Jiao,Xu, Qin,Shi, Min
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p. 3486 - 3490
(2016/07/28)
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- Tetrahydroisoquinoline compounds as preparing animal miticiding the application of the medicament
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The invention discloses application of a tetrahydroisoquinoline compound for preparing a drug killing animal mites. The compound has the molecular structure feature shown in the specification, wherein R is ortho-, meta- or para-alkyl, alkoxy, halogen, hydroxyl, nitro, trifluoromethyl, cyano group and the like. The compound has good activity in killing multiple animal mites like psoroptes communis cuniculi, which is superior to that of the clinical mite killing drug ivermectin, and has chemical stability and good compatibility with physiological environment.
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Paragraph 0023
(2016/10/07)
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- Single-Electron-Transfer Strategy for Reductive Radical Cyclization: Fe(CO)5 and Phenanthroline System
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An electron-transfer strategy using low-valent iron pentacarbonyl [Fe(CO)5] to generate radical species from alkyl iodides was achieved. A range of pyrrolidines, tetrahydrofurans, and carbocycles were synthesized via 5-exo cyclization reactions of alkyl radical intermediates generated by electron transfer from a system involving Fe(CO)5, 1,10-phenanthroline, and diisopropylamine. Moreover, tandem addition reactions with Michael acceptors were also explored. Photophysical and electrochemical studies support a mechanism that involves electron transfer from the low-valent Fe reductant to alkyl iodide.
- Hwang, Joon Young,Baek, Jong Hwa,Shin, Tae Il,Shin, Jung Ha,Oh, Jae Won,Kim, Kwang Pyo,You, Youngmin,Kang, Eun Joo
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supporting information
p. 4900 - 4903
(2016/10/18)
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- A facile one-pot protocol for the synthesis of tetrazolyl-tetrahydroisoquinolines via novel domino intramolecular cyclization/Ugi-azide sequence
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A facile one-pot, four-component domino reaction between 2-(2-bromoethyl)benzaldehyde, isocyanide, amine, and azide for the synthesis of tetrazolyl-tetrahydroisoquinoline derivatives has been developed. The reaction sequence involves intramolecular replacement of halide by iminium nitrogen followed by Ugi-azide reaction. The reaction is catalyst/additive free and takes place under ambient conditions with short reaction times to furnish products in good to excellent yields.
- Shinde, Anand H.,Archith,Malipatel, Srilaxmi,Sharada, Duddu S.
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p. 6821 - 6826
(2015/01/09)
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- A Phosphine-Catalyzed Novel Asymmetric [3+2] Cycloaddition of C,N-Cyclic Azomethine Imines with δ-Substituted Allenoates
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Catalytic asymmetric [3+2] cycloadditions of C,N-cyclic azomethine imines with δ-substituted allenoates have been developed in the presence of (S)-Me-f-KetalPhos, affording functionalized tetrahydroquinoline frameworks in good yields with high diastereo- and good enantioselectivities under mild condition. The substrate scope has been also examined. This is the first time that δ-substituted allenoates have been applied as a δ,γ-C-C bond participated C 2 synthon in asymmetric synthesis. Another round: Catalytic asymmetric [3+2] cycloaddition of C,N-cyclic azomethine imines with δ-substituted allenoates have been developed in the presence of (S)-Me-f-KetalPhos, affording functionalized tetrahydroquinoline frameworks in good yields with high diastereo- and good enantioselectivities under mild conditions. This is the first example applying δ-substituted allenoates as C 2 synthons in asymmetric δ,γ-C-C bond formation.
- Wang, De,Lei, Yu,Wei, Yin,Shi, Min
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p. 15325 - 15329
(2016/02/18)
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- Carbohydrate-derived iminium salt organocatalysts for the asymmetric epoxidation of alkenes
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A new family of carbohydrate-based dihydroisoquinolinium salts has been prepared and tested for potential as asymmetric catalysts for the epoxidation of unfunctionalized alkene substrates, providing up to 57% ee in the product epoxides.
- Bulman Page, Philip C.,Chan, Yohan,Liddle, John,Elsegood, Mark R.J.
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p. 7283 - 7305
(2017/09/13)
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- CuBr2 catalyzed bromination/oxidation of isochromans to benzaldehyde derivatives
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A series of isochromans were oxidized and brominated by using 1.2 equiv of CuBr2 in CH3CN at reflux to give the corresponding bromo benzaldehydes in moderate yields. A plausible mechanism for this transformation has been suggested.
- Zhou, Mei-Yan,Kong, Shan-Shan,Zhang, Ling-Qiong,Zhao, Ming,Duan, Jin-Ao,Ou-Yang, Zhen,Wang, Min
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p. 3962 - 3964
(2013/07/25)
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- N-Substituted 3,4-dihydroisoquinolinium ionic liquids as catalysts in alkenes epoxidation reactions
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Because of their high reactivity, epoxides are one of the most important groups of organic compounds. These substances are synthesised primarily by the catalytic oxidation of alkenes in the liquid or gaseous phase. This study investigated new catalytic systems for epoxidation reactions using functionalised ionic liquids. These ionic liquids serve as oxygen transfer agents during the reactions. Several N-substituted 3,4-dihydroisoquinolinium ionic liquids were synthesised, and their potential as catalysts for epoxidation reactions was investigated. Cyclic alkenes such as cyclohexene and cyclooctene were used as model olefins.
- Baj, Stefan,Be?ch, MacIej,Gibas, Miros?aw
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experimental part
p. 197 - 205
(2012/09/08)
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- Platonic hexahedron composed of six organic faces with an inscribed Au cluster
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The structures of nanomaterials determine their individual properties and the suprastructures they can form. Introducing anisotropic shapes and/or interaction sites to isotropic nanoparticles has been proposed to extend the functionality and possible suprastructure motifs. Because of symmetric anisotropy, Platonic solids with regular polygon faces are one of the most promising nanoscale structures. Introduction of Platonic solid anisotropy to isotropic nanomaterials would expand the functionality and range of possible suprastructure motifs. Here, we demonstrate a novel strategy to obtain nano-Platonic solids through the face coordination of square porphyrins on an inscribed Au sphere with adequate size. The face coordination of the multidentate porphyrin derivatives, with four acetylthio groups facing the same direction, on the Au cluster encased the Au cluster in a Platonic hexahedron with six porphyrin faces. Transmission electron microscopy, mass spectrometry, elemental analysis, and scanning tunnelling microscopy were used to confirm the formation of the nano-Platonic hexahedron.
- Sakamoto, Masanori,Tanaka, Daisuke,Tsunoyama, Hironori,Tsukuda, Tatsuya,Minagawa, Yoshihiro,Majima, Yutaka,Teranishi, Toshiharu
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supporting information; experimental part
p. 816 - 819
(2012/03/07)
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- Catalytic enantioselective 1,3-dipolar cycloaddition of C,N-cyclic azomethine imines with α,β-unsaturated aldehydes
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(Figure Presented) A yet-unexploited class of azomethine imines, C,N-cyclic azomethine imines, could be successfully employed in highly enantioselective 1,3-dipolar cycloaddition with enals catalyzed by titanium-BINOLate to give pharmaceutically attractive tetrahydroisoquinoline and piperidine motifs. Copyright
- Hashimoto, Takuya,Maeda, Yuko,Omote, Masato,Nakatsu, Hiroki,Maruoka, Keiji
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supporting information; experimental part
p. 4076 - 4077
(2010/05/15)
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- Cascade condensation, cyclization, intermolecular dipolar cycloaddition by multi-component coupling and application to a synthesis of (±)-crispine A
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A general approach for the synthesis of various nitrogen-containing heterocyclic compounds is described using an intermolecular dipolar cycloaddition reaction of azomethine ylides and nitrones. Stabilized and non-stabilized azomethine ylide dipoles or the related nitrones were generated by condensation of 4-, 5- or 6-halo-aldehydes with a readily available amino-acid, amino-ester or hydroxylamine to give an imine followed by cyclization and either decarboxylation or loss of a proton. After intermolecular cycloaddition with an activated dipolarophile, bicyclic or polycyclic (if the ylide dipole and/or dipolarophile contain a ring) amines were produced. A short synthesis of the alkaloid (±)-crispine A was achieved based on this tandem/domino 3-component coupling chemistry.
- Coldham, Iain,Jana, Samaresh,Watson, Luke,Martin, Nathaniel G.
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scheme or table
p. 1674 - 1679
(2009/06/27)
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- Highly efficient catalysts for epoxidation mediated by iminium salts
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A range of substituted dihydroisoquinolinium salts has been tested in the catalytic epoxidation of several alkenes. Catalyst loadings as low as 0.5 mol% have been used in the epoxidation of 1-phenylcyclohexene. Georg Thieme Verlag Stuttgart.
- Bulman Page, Philip C.,Buckley, Benjamin R.,Appleby, Louise F.,Alsters, Paul A.
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p. 3405 - 3411
(2007/10/03)
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- PROCESS FOR PURIFICATION OF ROPINIROLE
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The invention discloses an improved process for the purification of ropinirole hydrochloride by dissolving or suspending crude ropinirole base or its pharmaceutically acceptable salt in a suitable solvent, reacting with a nitrogenous base to form an imine derivative, optionally treating the reaction mixture with a base to adjust the pH, and isolating purified ropinirole hydrochloride. The invention also provides for a pharmaceutical composition comprising pure ropinirole hydrochloride as active ingredient.
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Page/Page column 19-20
(2010/02/13)
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- Benzo[f]azino[2,1-a]phthalazinium Cations: Novel DNA Intercalating Chromophores with Antiproliferative Activity
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New azaquinolizinium-type cations have been obtained from isochromane. The synthesis was completed over seven steps and included as the key feature an intramolecular Westphal condensation. This first example of the intramolecular process allowed the preparation of benzo[f]pyrido[2,1-a]phthalazinium and benzo[f]quino[2,1-a]phthalazinium salts, which were evaluated as DNA intercalators, DNA topoisomerase I inhibitors, and antiproliferative compounds. Both cationic systems behave as DNA intercalators and exhibit antiproliferative activity. The pentacyclic benzo[f]quino[2,1-a]phthalazinium cations also have an inhibitory effect on the catalytic activity of DNA topoisomerase I, without trapping of cleavage complexes. Structural characterization using density functional theory indicates that the fused ring systems are slightly nonplanar, and additional molecular modeling studies suggest a preferred orientation for the intercalating chromophores within a typical CpG or TpG intercalation site.
- Martínez, Valentín,Burgos, Carolina,Alvarez-Builla, Julio,Fernández, Gerónimo,Domingo, Alberto,García-Nieto, Raquel,Gago, Federico,Manzanares, Ignacio,Cuevas, Carmen,Vaquero, Juan J.
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p. 1136 - 1148
(2007/10/03)
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- Functionalized iminium salt systems for catalytic asymmetric epoxidation
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A range of dihydroisoquinolinium salts containing alcohol, ether, and acetal functionalities in the nitrogen substituent has been prepared and tested as asymmetric epoxidation catalysts, providing ee's of up to ca. 60%.
- Page,Rassias,Barros,Ardakani,Buckley,Bethell,Smith,Slawin
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p. 6926 - 6931
(2007/10/03)
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- The first example of an intramolecular Westphal reaction. Synthesis of a new aza-quinolizinium type system
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The first example of an intramolecular Westphal condensation is described. To test the utility of this reaction, new benz(f)azino[2,1- a]phthalazinium salts have been prepared from appropriate dicarbonyl precursors.
- Martinez-Barrasa, Valentin,Burgos, Carolina,Izquierdo, M. Luisa,Alvarez-Builla, Julio,Vaquero, Juan J.
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p. 4115 - 4118
(2007/10/03)
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- Development of large-scale syntheses of ropinirole in the pursuit of a manufacturing process
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Two plant syntheses of ropinirole {4-[2-(di-n-propyIamino)-ethyl]-1,3-dihydro-2H-indolin-2-one hydrochloride, SK&F-101468-A} using the ferric chloride mediated cyclisation of β-nitrostyrenes to form 3-chlorooxindoles as the key step are described. The first synthesis suffered the severe limitation of the final-step chemistry being nonselective in the reaction between di-n-propylamine and the bromide precursor to ropinirole as both substitution and elimination pathways were promoted and by-product formation at a level of 40% resulted. This problem was rectified in the latter synthesis by the more selective reaction between di-n-propylamine and the sulfonate ester precursor promoting ropinirole formation to a level of 88%. This second synthesis is now used as the commercial route, and problems (and their solutions) identified during the development of this route are now described. The identification of novel by-products which enabled the Sommelet oxidation step to be optimised is also reported. A unimolecular decomposition mechanism during hydrolysis of the hexaminium salt to form the key benzaldehyde intermediate is proposed and substantiated with experimental data.
- Hayler, John D.,Howie, Simon L. B.,Giles, Robert G.,Negus, Alan,Oxley, Paul W.,Walsgrove, Timothy C.,Whiter
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- Some synthetic approaches to ropinirole (SK and F 101468-A): A potent dopamine receptor agonist
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Three new routes to ropinirole (SK and F 101468-A, 1) are described each involving the preparation of 3-chlorooxindole intermediates of type 3 from β-nitrostyrenes as the pivotal step. The superiority of sulphonate esters 17a-c as direct precursors to 1 over the bromide 11 is also described.
- Hayler,Howie,Giles,Negus,Oxley,Walsgrove,Walsh,Dagger,Fortunak,Mastrocola
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p. 875 - 882
(2007/10/02)
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- Process for preparing substituted isoindolinone derivatives
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This invention relates to an improved process for the preparation of substituted indolinone derivatives using reductive cyclization conditions.
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