- Gold-Catalyzed Oxidative Aminocyclizations of Propargyl Alcohols and Propargyl Amines to Form Two Distinct Azacyclic Products: Carbene Formation versus a 3,3-Sigmatropic Shift of an Initial Intermediate
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Gold-catalyzed oxidations of propargyl alcohols with nitrones by using a P(tBu)2(o-biphenyl)Au+ catalyst, afforded bicyclic annulation products from the Mannich reactions of gold enolates. The same reactions of propargyl amines with nitrones by using the same gold catalyst gave distinct oxoarylation products. Our DFT calculations indicate that oxidation of propargyl alcohols with nitrones by using electron-rich gold catalysts lead only to gold carbenes, which can generate gold enolates or oxoarylation intermediates with enolate species having a barrier smaller than that of oxoarylation species.
- Chao, Tzu-Hsuan,Chen, Mu-Jeng,Liu, Rai-Shung,Raj, Antony Sekar Kulandai,Sasane, Amit Vijay
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supporting information
p. 16932 - 16938
(2020/11/30)
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- Copper-Catalyzed Synthesis of Polysubstituted Pyrroles through [3+1+1] Cycloaddition Reaction of Nitrones and Isocyanides
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An efficient, copper-catalyzed [3+1+1] cycloaddition reaction was developed for the expedient synthesis of pharmacologically interesting polysubstituted pyrroles from easily available nitrones and α-acidic isocyanides. The given approach features a new mo
- Tian, Zhuang,Xu, Jiaojiao,Liu, Bingxin,Tan, Qitao,Xu, Bin
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supporting information
p. 2603 - 2606
(2018/05/22)
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- Metal-free approach for the ?-proline mediated synthesis of nitrones from nitrosobenzene
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An efficient, and metal-free approach for the ?-proline mediated synthesis of nitrones from nitrosobenzene and benzaldehydes has been established. The reaction undergoes very efficiently at room temperature in methanol as a solvent. The reaction is assumed to involve that the initial formation of azomethine ylide and [2 + 3] cycloaddition of nitrosobenzene, followed by the subsequent retro [2 + 3] cycloaddition could offer the desired nitrone.
- Choi, Minho,Viji, Mayavan,Kim, Donghwan,Lee, Young Hee,Sim, Jaeuk,Kwak, Young-Shin,Lee, Kiho,Lee, Heesoon,Jung, Jae-Kyung
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p. 4182 - 4187
(2018/06/19)
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- Synthesis of 2,3-Disubstituted NH Indoles via Rhodium(III)-Catalyzed C-H Activation of Arylnitrones and Coupling with Diazo Compounds
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A rhodium-catalyzed intermolecular coupling between arylnitrones and diazo compounds by C-H activation/[4 + 1] annulation with a C(N2)-C(acyl) bond cleavage is reported, and 2,3-disubstituted NH indoles are directly synthesized in up to a 94% yield. A variety of functional groups are applicable to this reaction to give the corresponding products with high selectivity. Compared to other previously reported Rh(III)-catalyzed synthesis of homologous series, this method is simpler, more general, and more efficient.
- Guo, Xin,Han, Jianwei,Liu, Yafeng,Qin, Mingda,Zhang, Xueguo,Chen, Baohua
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p. 11505 - 11511
(2017/11/10)
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- LIC-KOR promoted nitrone reactivity: Stereoselective synthesis of highly conjugated imines and secondary amines
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The reactivity of metalated alkoxy-1,3-dienes and α-aryl-N-phenylnitrones in the presence of LIC-KOR base, equimolar mixture of alkyllithium (LIC) and potassium alcoxides (KOR), (Schlosser, 1994) [1] has been studied. A cascade reaction involving a E1cb p
- Parisotto, Stefano,Boggio, Paolo,Prandi, Cristina,Venturello, Paolo,Deagostino, Annamaria
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supporting information
p. 5791 - 5794
(2015/09/29)
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- Synthesis and evaluation of novel 4-[(3H,3aH,6aH)-3-phenyl)-4,6-dioxo-2- phenyldihydro-2H-pyrrolo[3,4-d]isoxazol-5(3H,6H,6aH)-yl]benzoic acid derivatives as potent acetylcholinesterase inhibitors and anti-amnestic agents
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The present study was designed to synthesize and evaluate pyrrolo-isoxazole benzoic acid derivatives as potential acetylcholinesterase (AChE) inhibitors for the management of Alzheimer's disease. The synthesis of pyrrolo-isoxazole benzoic acid derivatives involved ring opening cyclization of p-aminobenzoic acid with maleic anhydride to yield maleanilic acid, which in turn afforded N-arylmaleimide via ring closed cyclization. Azomethine-N-oxides were obtained by condensation of N-arylhydroxylamine with differently substituted benzaldehydes followed by refluxing of N-arylmaleimide with differently substituted azomethine-N-oxides to pyrrolo-isoxazole benzoic acid derivatives as cis- and trans-stereoisomers. The synthesized compounds were evaluated in vitro for AChE inhibitory activity in rat brain homogenate with donepezil as standard AChE inhibitor. Thereafter, the most potent test compound was evaluated for in vitro butyrylcholinesterase inhibitory activity and in vivo memory evaluation in scopolamine (0.4 mg/kg)-induced amnesia in mice by employing Morris water maze test. All pyrrolo-isoxazole benzoic acid derivatives demonstrated potent AChE inhibitory activity. Most of compounds exhibited similar activity to donepezil and four of them (7h, 7i, 8i, and 8h, IC50 = 19.1 ± 1.9-17.5 ± 1.5 nM) displayed higher inhibitory activity as compared to donepezil (21.5 ± 3.2 nM) with compound 8ia (IC50 = 17.5 ± 1.5 nM) being the most active one. The test compound 8ia also ameliorated scopolamine-induced amnesia in mice in terms of restoration of time spent in target quadrant (TSTQ) and escape latency time (ELT). It may be concluded that pyrrolo-isoxazole benzoic acid derivatives may be employed as potential AChE inhibitors.
- Anand, Preet,Singh, Baldev
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p. 521 - 530
(2012/03/09)
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- Synthesis and evaluation of hexahydropyrrolo[3,4-d]isoxazole-4,6-diones as anti-stress agents
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A series of 2,3-diphenyl-5-(naphthalen-1-yl)-4H-2,3,3a,5,6,6a- hexahydropyrrolo[3,4-d]isoxazole-4,6-dione derivatives were synthesized via 1,3-dipolar cycloaddition of azomethine N-oxides with N-(α-naphthyl) maleimide. The pyrrolo-isoxazole derivatives were assigned cis- and trans- configurations (3-A and 3-B) with respect to proton C3-H on azomethinic carbon on the basis of their 1H NMR. The reaction proceeds through cis- endo addition rule indicating the predominance of cis isomer. The cis- and trans- isomers of a prototype compound 3a i.e., compound 3a-A and compound 3a-B were evaluated for anti-stress activity in immobilization-induced acute stress. Compound 3a-A (5 and 10 mg/kg) and compound 3a-B (10 mg/kg) attenuated immobilization stress-induced behavioral alterations in Swiss albino mice suggesting that pyrrolo-isoxazole may serve as lead molecule for the development of anti-stress agents.
- Badru, Rahul,Anand, Preet,Singh, Baldev
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- Conversion of nitrosobenzenes to isoxazolidines: An efficient cascade process utilizing reactive nitrone intermediates
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Reactive nitrones can be generated directly in situ by an unusual reaction of nitrosobenzene with styrene. The Royal Society of Chemistry.
- Kang, Jun Yong,Bugarin, Alejandro,Connell, Brian T.
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supporting information; experimental part
p. 3522 - 3524
(2009/02/05)
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- 1,3-Dipolar cycloadditions. Part-XIII: Microwave irradiation assisted synthesis and spectroscopic investigations of C-aryl-N-phenyl and C-aryl-N-(4′-chlorophenyl)nitrones
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C-Aryl-N-phenylnitrones have been prepared in very high yields from N-phenylhydroxylamine and aryl aldehydes using the microwave irradiation technique within a few minutes. The synthesis of a new series of nitrones, viz. the series of C-aryl-N-(4′-chlorop
- Banerji, Avijit,Biswas, Pizush Kanti,Gupta, Maya,Saha, Rina,Banerji, Julie
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p. 1004 - 1010
(2008/09/19)
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- Microwave mediated synthesis of spiro-(indoline-isoxazolidines): Mechanistic study and biological activity evaluation
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Regioisomeric spiro-(indoline-isoxazolidines) have been synthesized in moderate yields by the cycloaddition reaction between ethyl (3-indolylidene) acetate and various substituted α,N-diphenylnitrones, using environmentally benign microwave technology. A
- Raunak,Kumar, Vineet,Mukherjee, Shubhasish,Poonam,Prasad, Ashok K.,Olsen, Carl E.,Sch?ffer, Susan J.C.,Sharma, Sunil K.,Watterson, Arthur C.,Errington, William,Parmar, Virinder S.
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p. 5687 - 5697
(2007/10/03)
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- ?-? Molecular Complexes with Nitrones: PartIV - Substituent Effect in the Complexation of Aryl Nitrones with Tetracyanoethylene and 1,4-Benzoquinones
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Charge-transfer complexes of some substituted nitrones with tetracyanoethylene and 1,4-benzoquinones have been studied spectrophotometrically.The stoichiometry and apparent formation constants of the complexes have been determined.From the energies of the charge-transfer transitions, the ionization potentials of the donors have been obtained.
- Nour El-Din, Ahmed M.
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p. 511 - 512
(2007/10/02)
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