Simple and efficient syntheses of 7-deazacaffeines, 9-deazatheophyllines, furo [2, 3-d] pyrimidines and furo [3, 2-d] pyrimidines from 5- or 6-substituted pyrimidines by means of intramolecular cyclization reactions are described.
BF3·OEt2-Mediated 1,3-Hydride Shift Followed by 6π Electrocyclization: An Efficient Route for the Synthesis of Pyridopyrimidine, Pyranoquinoline, and Phenanthroline Derivatives
作者:Krishna C. Majumdar、Sudipta Ponra、Raj Kumar Nandi
DOI:10.1002/ejoc.201101065
日期:2011.12
The synthesis of pyridopyrimidine, pyranoquinoline, and phenanthrolinederivatives can be easily and efficiently accomplished by the direct reaction of a 1-aminopenta-1,4-diene fragment, an aromatic aldehyde, and BF 3 ·OEt 2 in the absence of any metal catalyst. The notable features of this procedure are mild reaction conditions, good to high yields, and operational simplicity.
Indium(III) Chloride Catalyzed Convergent, Regioselective Synthesis of Annulated Quinoline and Pyridine Derivatives
作者:K. Majumdar、Raj Nandi、Sudipta Ponra
DOI:10.1055/s-0031-1290100
日期:2012.1
A direct convergent two-component regioselective synthesis of annulated pyridine motif from 1-aminopenta-1,4-diene fragment and aromatic aldehyde by indium(III) chloride catalyzed reaction has been developed through a concerted pathway. A series of potentially bioactive pyranoquinoline, phenanthroline, and pyridopyrimidine derivatives has been synthesized in high yields by this protocol.
An expedient approach involving BF3˙OEt2-catalyzed aza-Claisen rearrangement and palladium-catalyzed intramolecular Heck reaction for the synthesis of pyrimidine-fused azocine derivatives is described. The mechanistic interpretation of the plausible mode of cyclization is also described. uracil - aza-Claisen rearrangement - azocine - Heck reaction
Concise Access to Pyrimidine-Annulated Azepine and Azocine Derivatives by Ruthenium-Catalyzed Ring-Closing Metathesis
作者:K. Majumdar、Shovan Mondal、Debankan Ghosh
DOI:10.1055/s-0029-1219228
日期:2010.4
systems are commonly undertaken throughcyclization and cycloaddition reactions, but the formation of seven- and eight-membered-ring systems are not as abundant. An efficient and high-yielding method for the synthesis of seven- and eight-membered-ring nitrogen-containing heterocycles by ring-closingmetathesis is reported. uracil - azepine - azocine - ring-closingmetathesis