- ALTERNATE PROCESSES FOR THE PREPARATION OF PYRROLIDINE DERIVATIVES
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Aspects of the present application relate to process for the preparation of Pyrrolidine derivatives useful as key intermediates for active ingredients. Specific aspects relate to alternate process for the preparation of Upadacitinib intermediate, 4-ethylpyrrolidine-3-carboxylic acid, its ester or a salt thereof. Processes disclosed here in are cost effective and industrially viable as compared to known processes.
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Page/Page column 36
(2019/02/06)
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- Copper-Catalyzed Domino Synthesis of Benzo[4,5]imidazo[1,2-a]pyrimidin-4(10H)-ones using Cyanamide as a Building Block
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An efficient and practical copper-catalyzed domino synthesis of benzo[4,5]imidazo[1,2-a]pyrimidin-4(10H)-ones has been developed. The protocol uses N-(2-halophenyl)-3-alkylpropiolamides and cyanamide as the starting materials, inexpensive copper(I) iodide and pipecolinic acid as the catalyst and ligand, and the corresponding products were obtained in moderate to good yields.
- Lou, Zhenbang,Wu, Xudong,Yang, Haijun,Zhu, Changjin,Fu, Hua
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supporting information
p. 3961 - 3968
(2016/01/25)
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- Palladium-catalyzed oxidative aminocarbonylation by decarboxylative coupling: Synthesis of alkynyl amides
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Alkynyl amides were synthesized from a palladium-catalyzed coupling reaction of alkynyl carboxylic acids and amines under carbon monoxide. The reaction was conducted with palladium(II) acetate (5 mol-%) and silver(I) oxide (1.0 equiv.) in acetonitrile at 80 °C for 1 h. This method provides good to moderate product yields and good functional group tolerance towards ketone, ester, and nitrile groups.
- Hwang, Jinil,Choi, Jinseop,Park, Kyungho,Kim, Wonyoung,Song, Kwang Ho,Lee, Sunwoo
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p. 2235 - 2243
(2015/04/14)
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- Solvolysis of 1-pent-3-ynyl triflate. Mechanism of the homopropargyl rearrangement
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1-Pent-3-ynyl triflate (1b) was solvolyzed (25°C, 24 h) in ethanol-water with 2,6-lutidine as the buffer. Products were formed predominantly (97-98.5%) through direct substitution (ks processes) and elimination. As the water content increases, the yields of 2-methylcyclobutanone (7b) (formed through kΔ processes) also increase from 0.2% (100% ethanol) to 2.8% (50% ethanol). 1-Pent-3-ynyl triflate was solvolyzed in anhydrous trifluoroethanol (25°C, 24 h) in nine different experiments with nine different buffers. Sodium and calcium carbonate, 2,6-lutidine, pyridine, and quinoline all favored kΔ processes (88-65%), whereas potassium carbonate, triethylamine, and sodium trifluoroethoxide suppressed the formation of rearranged products. The products of the solvolyses include: 2-methylcyclobutenyl trifluoroethyl ether (5b); cyclopropyl methyl ketone (6b); 2-methylcyclobutanone (7b); pent-1-en-3-yne (13); 1-pent-3-ynol (15); 2-methylcyclobutanone bis(trifluoroethyl) acetal (16), and 1-pent-3-ynyl trifluoroethyl ether (17). In 80% trifluoroethanol-20% water (sodium carbonate buffer) the yields of rearranged products (kΔ) dropped to 46% - as expected for an increase in nucleophilicity of the solvent. A quantitative correlation exists between percent rearrangement of 1b and nucleophilicity of the solvent, as demonstrated by use of the Winstein-Grunwald-Swain equation. 1-Pent-3-ynyl triflate was synthesized with carbon-14 in the 1 position (1b-1-14C) and, separately, in the 3 position (1b-3-14C). 1-Pent-3-ynyl triflate was also prepared doubly labeled both with carbon-14 and with deuterium (1b-3-14C-1,1-d2). Isotope effects were determined for all isotope position isomers. These are: k/*k = 1.048 ± 0.003 (1b-1-14C); k/*k = 0.990 ± 0.005 (1b-3-14C); and Hk/Dk = 1.098 ± 0.004 (1b-1,1-d2). In addition, 1b-1,1-d2 on solvolysis in trifluoroethanol-sodium carbonate yields 2-methylcyclobutanone (7b) containing equal fractions of 7b-3-d2 and 7b-4-d2. The tracer and isotope effect experiments confirm the mechanistic conclusions arrived at through product distribution studies and, in addition, offer strong evidence for significant anchimeric assistance during the kΔ processes investigated.
- Hanack, Michael,Collins, Clair J.,Stutz,Benjamin, Ben M.
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p. 2356 - 2360
(2007/10/02)
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