- Iron-catalyzed aerobic C-H functionalization of pyrrolones
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The aerobic oxidation of pyrrolones catalyzed by Fe(OTf)3 to form reactive N-acyliminium ion intermediates that undergo nucleophilic additions with alcohols to give the corresponding products in moderate to good yields is described.
- Liu, Li-Wei,Wang, Zhen-Zhen,Zhang, Hui-Hui,Wang, Wan-Shu,Zhang, Ji-Zong,Tang, Yu
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p. 9531 - 9534
(2015/06/08)
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- Synthesis, X-ray crystal structure and optical properties of novel 2-aryl-3-ethoxycarbonyl-4-phenylpyrido[1,2-a]benzimidazoles
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A series of novel 2-aryl-3-ethoxycarbonyl-4-phenylpyrido[1,2-a] benzimidazole derivatives were synthesized by the tandem reaction of 2-benzoyl benzimidazole and (Z)-ethyl 4-bromo-3-arylbut-2-enoate in the presence of potassium carbonate. The compounds were characterized using IR, 1H-NMR, 13C-NMR, HRMS and the structure of 6f was further determined by X-ray crystallography. Both absorption and fluorescence spectra characteristics of the compounds were investigated in acetonitrile and dichloromethane. The results showed that the absorption maxima of the compounds varied from 220 to 284 nm, depending on the structure of 2-aryl group. The fluorescence results revealed that these compounds exhibited blue-green fluorescence (463-475 nm) in dilute solutions and showed acceptable fluorescence quantum yields (PL = 0.13-0.73) in dichloromethane. Copyright
- Chen, Xia,Yang, He,Feng, Lei,Jia, Jiong,Wang, Jianwu,Ge, Yanqing
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p. 382 - 389,8
(2020/07/30)
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- Enantioselective Rh-catalyzed hydrogenation of 3-aryl-4-phosphonobutenoates with a P-stereogenic BoPhoz-type ligand
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A series of chiral 3-aryl-4-phosphonobutyric acid esters were synthesized in high enantioselectivities (93-98% ee) via the Rh-catalyzed asymmetric hydrogenation of the corresponding 3-aryl-4-phosphonobutenoates using a P-stereogenic BoPhoz-type phosphine-aminophosphine ligand. The methodology has been successfully applied to the asymmetric synthesis of a potential GABA B antagonist, (R)-phaclofen, in high enantioselectivity.
- Duan, Zheng-Chao,Hu, Xiang-Ping,Zhang, Cheng,Zheng, Zhuo
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p. 8319 - 8321
(2011/03/17)
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- Rh-catalyzed asymmetric hydrogenation of γ-phthalimido-substituted α,β-unsaturated carboxylic acid esters: An efficient enantioselective synthesis of β-aryl-γ-amino acids
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(Chemical Equation Presented) A series of chiral β-aryl-γ-amino acid ester derivatives were synthesized in high enantioselectivities (93-97% ee) via the Rh-catalyzed asymmetric hydrogenation of γ-phthalimido-α, β-unsaturated carboxylic acid esters using highly modular chiral BoPhoz-type phosphine-aminophosphine ligands. The method has been applied successfully to the synthesis of several chiral pharmaceuticals including (R)-baclofen and (R)-rolipram with high enantioselectivities.
- Deng, Jun,Duan, Zheng-Chao,Huang, Jia-Di,Hu, Xiang-Ping,Wang, Dao-Yong,Yu, Sai-Bo,Xu, Xue-Feng,Zheng, Zhuo
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p. 4825 - 4828
(2008/03/15)
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- Co-catalyzed reductive cyclization of azido and cyano substituted α,β-unsaturated esters with NaBH4: enantioselective synthesis of (R)-baclofen and (R)-rolipram
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Sodium borohydride in combination with a catalytic amount of CoCl2 has been found to be an excellent catalytic system in reductive cyclizations of suitably substituted azido and cyano groups of α,β-unsaturated esters to afford γ and δ-lactams in high yields. The process has been demonstrated for the enantioselective synthesis of (R)-baclofen, (R)-rolipram, and (R)-4-fluorophenylpiperidinone, a key intermediate for (-)-paroxetine.
- Paraskar, Abhimanyu S.,Sudalai, Arumugam
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p. 4907 - 4916
(2007/10/03)
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- Synthesis of 3-arylidene and 3-cyclohexylidene benzofuran-2(3H)-ones via Claisen rearrangement
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Claisen rearrangement of aryl-allyl ethers bearing substituents on the allylic portion of the substrate have been reported to yield very interesting products. α-Aryloxymethyl cinnamates furnish 3-benzylidene and 3-benzylcoumarins after isomerisation while
- Balakumar, Arumugham,Janardhanam, Selvasekaran,Rajagopalan, Krishnamoorthy
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p. 313 - 317
(2007/10/02)
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- The Synthesis of Phosphonobaclofen, an Antagonist of Baclofen
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Phosphonobaclofen 3-amino-2-(4-chlorophenyl)propylphosphonic acid, has been synthesized in five steps from ethyl 3-(4-chlorophenyl)but-2-enoate, and is a specific antagonist of baclofen.The alternative synthetic pathways, involving conjugate addition of phosphite to 2-(4-chlorophenyl)propenenitrile and of cyanide to 2-(4-chlorophenyl)ethylphosphonate ester, failed.Cyanide ion did add efficiently to ethyl 3-(4-chlorophenyl)-2-diethoxyphosphinylprop-2-enoate and hydrogenation followed by hydrolysis of the product gave (2 S, 3 S)- and (2R, 3 R)-4-amino-3-(4-chlorophenyl)-2-phosphonobutanoic acid, which is also undergoing pharmacological evaluation.
- Chiefari, John,Galanopoulos, Speros,Janowski, Wit K.,Kerr, David I. B.,Prager, Rolf H.
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p. 1511 - 1518
(2007/10/02)
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