- Multiple-step, one-pot synthesis of 2-substituted-3-phosphono-1-thia-4-aza-2-cyclohexene-5-carboxylates and their corresponding ethyl esters
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The multiple-step, one-pot procedure for a series of 2-substituted-3-phosphono-1-thia-4-aza-2-cyclohexene-5-carboxylates, analogues of the natural, sulfur amino acid metabolite lanthionine ketimine (LK), its 5-ethyl ester (LKE) and 2-substituted LKEs is described. Initiating the synthesis with the Michaelis-Arbuzov preparation of α-ketophosphonates allows for a wide range of functional variation at the 2-position of the products. Nine new compounds were synthesized with overall yields range from 40 to 62%. In addition, the newly prepared 2-isopropyl-LK-P, 2-n-hexyl-LKE-P and 2-ethyl-LKE were shown to stimulate autophagy in cultured cells better than that of the parent compound, LKE.
- Shen, Dunxin,Hensley, Kenneth,Denton, Travis T.
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- Facile enolisation of α-ketophosphonates
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A number of α-ketophosphonate are prepared and shown to be easily enolised. An X-ray crystal structure determination of a β-phenyl-α-ketophosphonate shows the molecule to be present as hydrogen bonded dimers and demonstrates the presence of enol tautomer
- Afarinkia, Kamyar,Echenique, Juan,Nyburg, Stanley C.
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Read Online
- Asymmetric hydrogenation of α- Or β-acyloxy α,β- unsaturated phosphonates catalyzed by a Rh(i) complex of monodentate phosphoramidite
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The Rh(i) complex of a monodentate phosphoramidite bearing a primary amine moiety (DpenPhos) has been disclosed to be highly efficient for the asymmetric hydrogenation of a variety of α- or β-acyloxy α,β- unsaturated phosphonates, providing the corresponding biologically important chiral α- or β-hydroxy phosphonic acid derivatives with excellent enantioselectivities (90->99% ee).
- Zhang, Jinzhu,Dong, Kaiwu,Wang, Zheng,Ding, Kuiling
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p. 1598 - 1601
(2012/03/22)
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- Phenyl-, benzyl-, and unsymmetrical hydroxy-methylenebisphosphonates as dronic acid ester analogues from α-oxophosphonates by microwave-assisted syntheses
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The microwave (MW)-assisted addition of dialkyl phosphites to α-oxophosphonates was investigated and optimized under solventless conditions to provide the phenyl- and benzyl-hydroxy-methylenebisphosphonates efficiently by suppressing the rearrangement sid
- Keglevich, Gyoergy,Gruen, Alajos,Molnar, Istvan Gabor,Greiner, Istvan
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experimental part
p. 640 - 648
(2011/12/21)
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- Highly enantioselective synthesis of α-hydroxy phosphonic acid derivatives by Rh-catalyzed asymmetric hydrogenation with phosphine- phosphoramidite ligands
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(Chemical Equation Presented) A class act: Unsymmetrical hybrid phosphine-phosphoramidite ligands with central and axial chirality are applied to the highly enantioselective hydrogenation of various enol ester phosphonates (see scheme; cod = cycloocta-1,5-diene). Enantioselectivities up to 99.9% ee are obtained for all classes of β-aryl, β-alkoxy, and β-alkyl substrates.
- Wang, Dao-Yong,Hu, Xiang-Ping,Huang, Jia-Di,Deng, Jun,Yu, Sai-Bo,Duan, Zheng-Chao,Xu, Xue-Feng,Zheng, Zhuo
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p. 7810 - 7813
(2008/09/19)
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- New efficient synthesis of 1-hydroxymethylene-1,1-bisphosphonate monomethyl esters
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A new efficient procedure for the synthesis of 1-hydroxymethylene-1,1- bisphosphonate monomethyl esters in three steps from acid chlorides is reported here. Georg Thieme Verlag Stuttgart.
- Migianu, Evelyne,Guénin, Erwann,Lecouvey, Marc
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p. 425 - 428
(2007/10/03)
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- Synthesis of some α-ketophosphonates comprising mobile hydrogens in position α: Spectroscopic characteristics of 1H, 13C, 31P NMR and IR reactivities among amines and hydrazine derivatives
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In the present work we describe the keto-enol equilibrium of some acylphosphonates 1 by means of 1H, 13C, 31P NMR, and IR data which show that the enol form has E configuration. The keto/enol ratio is determined on the basis of 31P NMR data. The reactivity of 1 with hydrazines derivatives and primary amines are reported. The structure of all compounds is determined by 1H, 13C, 31P NMR, and IR.
- Hassen, Zied,Akacha, Azaiez Ben,Zantour, Hedi
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p. 2241 - 2253
(2007/10/03)
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- A practical access to α-phosphonoenamides
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Reaction of α-oximinophosphonates first with acetic anhydride then with iron powder and acetic acid at 50-60 °C results in the clean formation of an E-Z mixture of α-phosphonoenacetamides, which are immediate precursors to α-aminophosphonic acids.
- Quiclet-Sire, Béatrice,Zard, Samir Z.,Zhang, Haiwen
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p. 404 - 408
(2007/10/03)
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