731-06-6Relevant academic research and scientific papers
Diethyl phosphite mediated reductive [1 + 4] annulation of α-ketoesters with α, β-unsaturated ketones and synthesis of polysubstituted 2,3-dihydrofurans
Xue, Feixue,Chen, Xiangyu,He, Zhengjie
, (2022/01/24)
A diethyl phosphite mediated reductive [1 + 4] annulation of α-ketoesters with α, β-unsaturated ketones has been developed, which provides an effective and simple method to prepare polysubstituted 2,3-dihydrofurans bearing a quaternary carbon center in fair to excellent yields. In the reaction, the in situ generated [1,2]-phospha-Brook rearrangement adduct of phosphite and α-ketoester presumably serves as C1 synthon. This work accordingly complements the phosphorus reagent-mediated C1 synthon source in the [1 + 4] annulation reactions.
1-Aryl-3-azabicyclohexanes, a New Series of Nonnarcotic Analgesic Agents
Epstein, Joseph W.,Brabander, Herbert J.,Fanshawe, William J.,Hofmann, Corris M.,McKenzie, Thomas C.,et al.
, p. 481 - 490 (2007/10/02)
A series of 1-aryl-3-azabicyclohexanes was synthesized by hydride reduction of 1-arylcyclopropanedicarboximides.Hydroxyphenyl analogues 20, 22, and 24 were prepared by EtSNa-DMF ether cleavage of the corresponding methoxyphenyl analogues 2m, 2n, and 23, respectively, with the secondary amines 20 and 22 going through the N-formyl intermediates 19 and 21.The p-ethoxy analogue 26 was obtained by O-ethylation of 19, followed by base hydrolysis of the amide 25.The greatest analgesic potency in mouse writhing and rat paw-pain assays was observed for para-substituted compounds.Bicifadine, 1-(4-methylphenyl)-3-azabicyclohexane (2b), was the most potent member of the series and is presently undergoing clinical trials in man.Analgesic activity of 2b is limited to the (+) enantiomer 2v, which has the 1R,5S absolute configuration as determined by single-crystal X-ray analysis.The N-methyl analogue (27d) of 2b showed significant analgesic potency, whereas the N-allyl (27a), N-(cyclopropylmethyl) (27b), and N-(n-hexyl) (27c) analogues were inactive.Bicifadine (2b) showed a nonnarcotic profile different from analogous azabicycloalkane and 3-phenylpyrrolidine analgesics.
