Synthesis of 1,3-Teraryls Through Carbanion Induced Ring Transformation of Functionalised Pyran-2-ones
作者:Atul Goel、Pratibha Srivastava、Mahendra Nath、Vishnu J. Ram
DOI:10.1055/s-1998-2008
日期:1998.2
1,3-Teraryls 2 were synthesised by reaction of 6-aryl-3-methoxycarbonyl-4-(methylthio)-2H-pyran-2-ones 1 a with aryl methyl ketones. An analogous reaction with 6-aryl-3-cyano-4-(methylthio)-2H-pyran-2-ones 1 b and aryl methyl ketones failed to yield cyano-substituted 1,3-teraryls, but afforded (4,6-diarylpyran-2-ylidene)acetonitriles 4 in poor yields.
6- 芳基-3-甲氧羰基-4-(甲硫基)-2H-吡喃-2-酮 1 a 与芳基甲基酮反应合成了 1,3-三芳基 2。6- 芳基-3-氰基-4-(甲硫基)-2H-吡喃-2-酮 1 b 与芳基甲基酮的类似反应未能得到氰基取代的 1,3-三芳基化合物,但得到了 (4,6-二芳基吡喃-2-亚基)乙腈 4,产率较低。
A regioselective synthesis of aryl substituted arylacetates through ring transformation by ethyl levulinate
作者:Ramendra Pratap、Vishnu Ji Ram
DOI:10.1016/j.tetlet.2006.05.071
日期:2006.7
A regioselective synthesis of sterically hindered ethyl arylacetates in one step through ring transformation of suitably functionalized 6-aryl-3,4-disubstituted-2H-pyran-2-ones with ethyl levulinate at room temperature in excellent yields is described.
Regioselective Syntheses of Functionalized 2-Aminopyridines and 2-Pyridinones through Nucleophile-Induced Ring Transformation Reactions
作者:Atul Goel、Fateh V. Singh、Ashoke Sharon、Prakas R. Maulik
DOI:10.1055/s-2005-862365
日期:——
An efficient one-pot synthesis of 2-amino-6-aryl-4-methylsulfanylpyridines and 6-aryl-3-cyano-4-methylsulfanyl-2(1H)-pyridinone has been illustrated through ring transformation of 6-aryl-3-cyano-4-methylsulfanyl-2H-pyran-2-ones by urea through different reaction conditions. Various solvents and bases were employed to selectively prepare either 2-aminopyridines or 2-pyridinones. In case of direct fusion of 2H-pyran-2-one with urea in solvent-free conditions, both the products were obtained in 1:1 ratio, while the reaction in pyridine at reflux temperature exclusively afforded 2-aminopyridine in 80-90% yield. The reaction of 6-aryl-3-carbomethoxy-4-methylsulfanyl-2H-pyran-2-ones with urea at 150 °C afforded 2-pyridinone derivatives in good yield (70-80%).
Ring transformation reactions part IV: 6-Aryl-3-methoxy-carbonyl-4-methylthio-2H-pyran-2-one, a novel synthon for the synthesis of 1,3-terphenyls from aryl ketones
作者:Vishnu Ji Ram、Atul Goel
DOI:10.1016/0040-4039(95)02081-0
日期:1996.1
4′-Methoxycarbonyl-5′-methylthio-1′,3′-terphenyls (3) and methyl (4,6-diarylpyran-2-ylidene)acetate (4) are synthesized from 6-aryl-3-methoxy-carbonyl-4-methylthio-2H-pyran-2-ones (1). The salient feature of this procedure is to provide symmetrical, unsymmetrical and heteroaryl terphenyls in single step.
Regioselective Synthesis of Highly Functionalized Biaryls through Carbanion Induced Ring Transformation of 2<i>H-</i>Pyran-2-ones
作者:Vishnu Ji Ram、Abhishek Shanker Saxena、Atul Goel
DOI:10.1055/s-2002-33538
日期:——
An expedient synthesis of highly functionalized unsymmetrical biaryls 3 of which one of the two phenyl rings substituted with carbomethoxy, amino and nitrile functionalities is described and illustrated by carbanion induced ring transformation of 6-aryl-3-carbomethoxy-4-methylsulfanyl-2H-pyran-2-one 1 using malononitrile 2 as a source of carbanion in moderate yield.