- Efficient Diastereoselective Three-Component Synthesis of Pipecolic Amides
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An efficient Ugi-type three-component reaction (U-3CR) for the synthesis of pipecolic amides is reported. The U-3CR between electronically diverse isocyanides, carboxylic acids and 4-substituted Δ1-piperideines proceeds in a highly diastereoselective fashion. The Δ1-piperideines are obtained by NCS-mediated oxidation of the corresponding 4-substituted piperidines, which in turn are generated by an efficient two-step procedure involving the alkylation of 4-picoline and subsequent catalytic hydrogenation of the pyridine ring. We demonstrate the utility of this U-3CR, in combination with the convertible isocyanide 2-bromo-6-isocyanopyridine, in the synthesis of the anticoagulant argatroban.
- van der Heijden, Gydo,van Schaik, Timo B.,Mouarrawis, Valentinos,de Wit, Martin J. M.,Velde, Christophe M. L. Vande,Ruijter, Eelco,Orru, Romano V. A.
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supporting information
p. 5313 - 5325
(2019/06/10)
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- Determination of the configuration in six-membered saturated heterocycles (N, P, S, Se) and their oxidation products using experimental and calculated NMR chemical shifts
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The six-membered saturated heterocycles - 4-tert-butyl-1-methylpiperidine, 4-tert-butyl-1-methylphosphine, 4-tert-butyl-tetrahydro-2H-thiopyran, and 4-tert-butyl-tetrahydro-2H-selenopyran - were prepared as suitable model compounds with well-defined geometry for an NMR study of their oxidation products. The corresponding epimeric N-oxides, phosphinoxides, sulfoxides, and selenoxides were obtained by standard chemical preparation and also by in situ oxidation with meta-chloroperbenzoic acid directly in the NMR tube. The experimental 1H and 13C chemical shifts were compared with corresponding calculated data obtained by GIAO approach with DFT, MP2, and HF methods and various basis sets. The correlation of experimental versus calculated data showed the possibility to determine the stereochemistry of the epimeric oxidation products using fast DFT B3LYP/6-31G* method for both geometry optimization and NMR chemical shifts calculation.
- Budesinsky, Milo?,Vaněk, Václav,Dra?ínsky, Martin,Pohl, Radek,Po?tová-Slavětínská, Lenka,Sychrovsky, Vladimír,Pícha, Jan,Císa?ová, Ivana
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p. 3871 - 3886
(2014/06/09)
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- PHENYL METHANESULFONAMIDE DERIVATIVES USEFUL AS MGAT - 2 INHIBITORS
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The present invention provides compounds of Formula I or a pharmaceutical salt thereof, where the variables for R1, R2, and R3 are as described herein; methods of treating a condition such as hypertriglyceridemia; and processes for preparing the compounds.
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Page/Page column 9
(2013/08/15)
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