99447-81-1Relevant academic research and scientific papers
Synthesis of Benzimidazolones via One-Pot Reaction of Hydroxylamines, Aldehydes, and Trimethylsilyl Cyanide Promoted by Diacetoxyiodobenzene
Zhang, Huaiyuan,Huang, Danfeng,Wang, Ke-Hu,Li, Jun,Su, Yingpeng,Hu, Yulai
, p. 1600 - 1609 (2017)
A novel and efficient PhI(OAc)2-promoted one-pot reaction of aromatic hydroxylamines, aldehydes, and TMSCN in the presence of BF3·Et2O is described. A wide variety of N-substituted benzimidazolones are obtained with satisfactory yields under mild reaction conditions. The method was proven to be efficient for the synthesis of benzimidazolone derivatives from readily available starting materials.
Catalytic Diastereo- and Enantioselective Synthesis of 2-Imidazolinones
Martínez-Pardo, Pablo,Blay, Gonzalo,Escrivá-Palomo, Alba,Sanz-Marco, Amparo,Vila, Carlos,Pedro, José R.
supporting information, p. 4063 - 4066 (2019/06/17)
Chiral cyclic ureas (2-imidazolinones) were prepared by the reaction of nitrones and isocyanoacetate esters using a multicatalytic system that combines a bifunctional Br?nsted base-squaramide organocatalyst and Ag+ as a Lewis acid. The reaction could be achieved with a range of nitrones derived from aryl- and cycloalkylaldehydes with moderate diastereo- and good enantioselectivity. A plausible mechanism involving an initial formal [3 + 3] cycloaddition of the nitrone and isocyanoacetate ester, followed by rearrangement to an aminoisocyanate and cyclization to the imidazolinone, is proposed.
Nickel(II)-Catalyzed Enantioselective 1,3-Dipolar Cycloaddition of Nitrones with α,β-Unsaturated Acylcarboxylates
Xie, Lei,Yu, Xuan,Li, Jiaqi,Zhang, Zhenhua,Qin, Zhaohai,Fu, Bin
supporting information, p. 657 - 661 (2017/02/05)
The highly enantioselective 1,3-dipolar cycloaddition of nitrones with α,β-unsaturated acylcarboxylates was realized for the first time by using a chiral bis(indano-oxazoline)-based Ni complex. The reaction proceeded smoothly under mild conditions and provided isoxazolidines with three contiguous stereocenters in high yields with excellent diastereoselectivities (>20:1 dr) and enantioselectivities (up to 99 % ee). The reaction was scaled up to the gram scale, and the products were readily transformed into γ-amino alcohols and other potentially bioactive compounds.
1,3-dipolar cycloaddition reactions leading to the synthesis of new 2,3,5-triaryl-4h,2,3,3a,5,6,6a-hexahydropyrrolo[3,4-d]isoxazole-4,6-diones
Kaur, Anjandeep,Singh, Baldev
, p. 1421 - 1429 (2015/04/27)
Cycloaddition of C,N-diphenylnitrones 1 to N-aryl maleimides 2 afforded two diastereomeric isoxazolidines with high selectivity. The structure and steric configuration of the adducts have been assigned on the basis of 1H NMR, 1H NMR COSY, 13C NMR and IR spectroscopy. The π-π stacking interactions between maleimide's and nitrone's aromatic rings during the 1,3-dipolar cycloaddition were assumed to control the exo-endo selectivity of the reaction. Thus, the exo-endo ratio depends upon the position of the substituent present on the C-phenyl ring of the C,N-diphenylnitrones.
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
Anand, Preet,Singh, Baldev
, p. 521 - 530 (2012/03/09)
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.
Synthesis and evaluation of hexahydropyrrolo[3,4-d]isoxazole-4,6-diones as anti-stress agents
Badru, Rahul,Anand, Preet,Singh, Baldev
, p. 81 - 91 (2012/03/22)
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.
Studies of multicomponent Kinugasa reactions in aqueous media
McKay, Craig S.,Kennedy, David C.,Pezacki, John Paul
supporting information; experimental part, p. 1893 - 1896 (2009/07/05)
Micelle-promoted, copper-catalyzed multicomponent Kinugasa reactions were studied in aqueous media. Reactions were performed in a 'single pot' for a series of in situ generated C,N-diphenylnitrones with Cu(I) phenylacetylide providing β-lactams in yields of 45-85%. Substituents affect the reaction by either accelerating cycloaddition or minimizing side reactions.
?-? Molecular Complexes with Nitrones: PartIV - Substituent Effect in the Complexation of Aryl Nitrones with Tetracyanoethylene and 1,4-Benzoquinones
Nour El-Din, Ahmed M.
, p. 511 - 512 (2007/10/02)
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.
