7492-87-7Relevant academic research and scientific papers
α,β-Unsaturated Nitriles: Stereoselective Conjugate Addition Reactions
Fleming, Fraser F.,Hussain, Zahid,Weaver, Douglas,Norman, Richard E.
, p. 1305 - 1309 (1997)
Dithiane anions undergo intramolecular conjugate additions with α,β-unsaturated nitriles when a dithiane anion is tethered to N-1 of the 3-cyano-1,4,5,6-tetrahydropyridine nucleus. 3-Cyano-1-[2-(1,3-dithianyl-2-yl)ethyl]-1,4,5,6-tetrahydropyridine (1a) and the one-carbon homologue 1b cyclize in the presence of 12-crown-4 to generate indolizidine 3 and quinolizidine 9, in which the nitrile group exhibits a strong, thermodynamic preference for the axial orientation. Oxidation of 1b provides dithiane S-oxide 10 that undergoes a highly stereoselective conjugate addition to provide crystalline quinolizidine 13. The X-ray structure of 13 is reported and corroborates our "peg-ina-pocket" principle for stereoselective conjugate additions with α,β-unsaturated nitriles.
New synthetic approach to 4-(3-aminopropyl)-5-amino-1-methylpyrazole starting from 3-cyanopyridine
Ohigashi, Atsushi,Temmaru, Kiyoshi,Hashimoto, Norio
, p. 159 - 162 (2006)
A short and practical method for the synthesis of 4-(N-Boc-3-aminopropyl)- 5-(N-tritylamino)-1-methylpyrazole (3), side chain of an anti-Pseudomonas aeruginosa cephalosporine FR259647, 1, was established by utilizing a regioselective enamine exchange with N-methylhydrazine and 1,4,5,6-tetrahydro- pyridine-3-carbonitrile (8), followed by a subsequently occurring intramolecular cyclization and aromatization, starting from a cheap 3-cyanopyridine (7).
Homogeneous Hydrogenation with a Cobalt/Tetraphosphine Catalyst: A Superior Hydride Donor for Polar Double Bonds and N-Heteroarenes
Duan, Ya-Nan,Du, Xiaoyong,Cui, Zhikai,Zeng, Yiqun,Liu, Yufeng,Yang, Tilong,Wen, Jialin,Zhang, Xumu
supporting information, p. 20424 - 20433 (2019/12/27)
The development of catalysts based on earth abundant metals in place of noble metals is becoming a central topic of catalysis. We herein report a cobalt/tetraphosphine complex-catalyzed homogeneous hydrogenation of polar unsaturated compounds using an air- and moisture-stable and scalable precatalyst. By activation with potassium hydroxide, this cobalt system shows both high efficiency (up to 24 000 TON and 12 000 h-1 TOF) and excellent chemoselectivities with various aldehydes, ketones, imines, and even N-heteroarenes. The preference for 1,2-reduction over 1,4-reduction makes this method an efficient way to prepare allylic alcohols and amines. Meanwhile, efficient hydrogenation of the challenging N-heteroarenes is also furnished with excellent functional group tolerance. Mechanistic studies and control experiments demonstrated that a CoIH complex functions as a strong hydride donor in the catalytic cycle. Each cobalt intermediate on the catalytic cycle was characterized, and a plausible outer-sphere mechanism was proposed. Noteworthy, external inorganic base plays multiple roles in this reaction and functions in almost every step of the catalytic cycle.
Reactivity of 2-Cyano-1,4,5,6-tetrahydro-1-pyridinecarboxylic Acid Esters Towards Various Nucleophiles: Regio- and Stereoselectivity of the Attack
Stanetty,Mihovilovic,Mereiter
, p. 1061 - 1072 (2007/10/03)
The synthesis and reactivity of the title compounds towards nucleophiles are discussed. The regio- and diastereoselectivity of the attack is highly dependent on the carbamic ester and the type of nucleophile applied. Both Michael type addition across the
