3489-08-5Relevant academic research and scientific papers
Chemoselective Reduction of the P=O Bond in the Presence of P–O and P–N Bonds in Phosphonate and Phosphinate Derivatives
Sowa, Sylwia,Pietrusiewicz, K. Micha?
supporting information, p. 923 - 938 (2019/01/22)
Chemoselective reduction of the strong P=O bond in the presence of weaker P–O (ester) and P–N (amide) bonds in phosphonic acid derivatives has constituted an unresolved problem in organophosphorus chemistry for years. This long-standing problem is now solved for biologically relevant α-hydroxy and α-amino phosphonic as well as phosphinic acids esters and amides. The reduction of the P=O bond without concomitant scission of the ester and amide bonds is affected by use of BH3, a mild reducing agent, which affords the corresponding borane protected PIII phosphonite and phosphinite derivatives in one step. A mechanistic rationale is proposed for the role played by neighboring OH and NHR groups in facilitating the reduction, and for the observed chemo- and stereoselectivity. The reduction methodology described opens previously unavailable synthetic options in chemistry of α-functionalized phosphonic and phosphinic acids by offering a unique possibility for direct modifications of oxidation level of the P-center in these compounds.
Imino Diels-Alder reactions: Efficient synthesis of 2-aryl-4-(2'- oxopyrrolidinyl-1')-1,2,3,4-tetrahydroquinolines catalyzed by Antimony(III) Sulfate
Srinivasa, Aswathanarayana,Mahadevan, Kittappa M.,Hulikal, Vijaykumar
experimental part, p. 255 - 259 (2009/05/26)
Antimony(III) sulfate is found to catalyze the imino Diels-Alder reaction of Schiff's bases with N-vinylpyrrolidin-2-one to afford 2-aryl-4-(2'- oxopyrrolidinyl-1')-1,2,3,4-tetrahydroquinolines. One-pot synthesis of 1,2,3,4-tetrahydroquinolines from 3-nit
A convenient and facile synthesis of new thiazole derivatives
El Rady, Eman A.
body text, p. 1659 - 1671 (2009/08/07)
4-Chloro-2,3-dihydrothiazole-5-carboxaldehyde reacted with some nucleophilic reagents such as hydrazine hydrate, phenyl hydrazine, urea, thiourea, semicarbazide, cyanoacetamide, cyanothio-acetamide, cyanoacetohydrazide, 2-phenylenediamine, 2-aminophenol, 5-amino[1,2,4]triazole and 3-aminopyrazole in ethanol solution at reflux in the presence of catalytic amount of triethyl-amine afforded new polysubstituted thiazolo[4,5-c]pyrazole, thiazolo[4,5-d]-pyrimidine, thiazolo[4,5-b]-pyridine, thiazolo[4,5-b][1,5] benzodiazepine, thiazolo[4,5-b] [1,5]benzoxazepine, thiazolo[4′, 5′:6,5]-pyrimido[1,2-b][1,2,4]triazole and thiazolo[4′, 5′:6,5]pyrimido[1,2-b]pyrazole derivatives in good yields. The structure of the new compounds were confirmed based on IR, 1 H-,13C-NMR, mass spectral, and elemental analysis. Copyright Taylor & Francis Group, LLC.
