- Cross-linked polystyrene-TiCl4 complex as a reusable Lewis acid catalyst for solvent-free Knoevenagel condensations of 1,3-dicarbonyl compounds with aldehydes
-
Cross-linked polystyrene copolymer beads with the average particle size in the range of (50–80 mesh size) were prepared by a new method, characterized and functionalized with titanium tetrachloride to afford the corresponding polystyrene?titanium tetrachloride complex in one step reaction and characterized by FT-IR, UV, TGA, DSC, XRD, SEM, BET. This polymer metal complex (PS/TiCl4) was used as a heterogeneous, recoverable, reusable Lewis acid for solvent-free Knoevenagel condensations of 1,3-diketones with aromatic aldehydes under green and mild conditions. The rate of reactions was found to decrease with an increasing percentage of crosslinking and the mesh size of the copolymer beads. This complex showed good stability and catalytic activity in the Knoevenagel reactions.
- Rahmatpour, Ali,Goodarzi, Niloofar
-
-
- Iron(III) chloride-catalyzed convenient one-pot synthesis of β-acetamido carbonyl compounds
-
A one-pot multi-component reaction of aldehydes, enolizable ketones or 1,3-dicarbonyls, acetonitrile/benzonitrile, and acetyl chloride is described for the preparation of β-acetamido carbonyl compounds using FeCl3·6H2O as a mild, inexpensive, and highly efficient catalyst. The effect of substrate as well as substituent for multi-component reaction versus Knoevenagel condensation is also illustrated. The key features of this methodology are operational simplicity, mild reaction conditions, and good yields.
- Khan, Abu T.,Parvin, Tasneem,Choudhury, Lokman H.
-
p. 5593 - 5601
(2007/12/25)
-
- AN IMPROVED PROCESS FOR THE PREPARATION OF PURE NISOLDIPINE
-
Nisoldipine is prepared by the process according to this invention by cyclocondensing 3-Aminocrotonoic acid isobutyl ester with 2-(2-nitrobenzylidene)-3-oxo-butyric acid methyl ester in the presence of a water immiscible organic solvent such as toluene and an aprotic organic solvent. The reaction product is recovered after refluxing with diisopropyl ether. Water miscible aprotic solvent may be selected from ethers and glycol ethers.
- -
-
Page/Page column 4; 5; 6-7; 9
(2008/06/13)
-
- Pyrano[3,4-c]quinolines from 1-desaza-1-oxa-nifedipine
-
The reaction of the 1,5-diketone 1 with acetic anhydride/acetic acid in the presence of zinc chloride yields the 1-desaza-1-oxa-nifedipine 2 and the annulated lactone 3 as a by-product. The structures of 2 and 3 are confirmed by X-ray structure analysis. The pH-dependent reduction of the nitro group from 2 leads to the pyrano[3,4-c]quinolines 4Aa, b by ring closure. The cyclic hydroxamic acid 4Aa represents a weak, non-selective inhibitor of 5-, 12- and 15-lipoxygenase of human full-blood.
- Goerlitzer, Klaus,Trittmacher,Jones,Frohberg,Drutkowski
-
p. 539 - 542
(2007/10/03)
-
- Electrochemical Behaviour of an Unsymmetrical 4-(o-Nitrophenyl)-1,4-Dihydropyridine in Protic Medium.
-
The electrochemical behaviour of 3-cyano-5-methoxycarbonyl-2,6-dimethyl-4(o-nitrophenyl)-1,4-dihydropyridine and the corresponding N-methyl derivative have been investigated in hydroalcoolic medium.The 4 electron reduction leads to an amino-benzonaphtyrid
- David, J. Y.,Hurvois, J. P.,Tallec, A.,Toupet, L.
-
p. 3181 - 3196
(2007/10/02)
-
- Synthesis of 1,4-dihydro-2,6-dimethyl-4-(substituted phenyl)-5-N-methylaminocarbonyl-pyridine-3-carboxylate
-
Michael addition of β-amino-N-methylcrotonamide to aralkylideneacetoacetic acid ester is followed by ring closer to give novel 4-aryl-1,4-dihydro-2,6-dimethyl-5-N-methylaminocarbonylpyridine-3-carboxylates (5).
- Sainani, J. B.,Shah, A. C.,Arya, V. P.
-
p. 573 - 575
(2007/10/03)
-