Azomethinylides generated by reaction of difluorocarbene with N-alkyl- and N-arylimines of O-acylated salycilaldehyde undergo intramolecular 1,3-dipolar cycloaddition to the ester carbonyl group forming regioselectively 2,5-epoxy-1,4-benzoxazepine derivatives.
Convenient Synthesis of 3-Vinyl and 3-Styryl Coumarins
摘要:
A variety of 2-hydroxy aldehydes on reaction with 3-butenoic acid afford in a one-pot reaction the corresponding 3-vinylcoumarins. As expected, extension of the delocalized pi-electron system accomplished by Heck coupling reactions with aryl halides results in an increased fluorescence of the compounds whose applicability is yet to be established.
A new domino Knoevenagel-hetero-Diels–Alder reaction: an efficient catalyst-free synthesis of novel thiochromone-annulated thiopyranocoumarin derivatives in aqueous medium
An efficient catalyst-free synthesis of novel pentacyclic thiochromone-annulated thiopyranocoumarin derivatives is achieved via domino Knoevenagel-hetero-Diels–Alder reaction of 4-hydroxy dithiocoumarin and O-acrylated salicylaldehyde derivatives in H2O as solvent. The products are formed in good yields with high regio- and stereo-selectivity.
Peptides can be converted to highly active compounds by introducing appropriate substituents on the suitable amino acid residue. Although modifiable residues in peptides can be systematically identified by peptide scanning methodologies, there is no practical method for optimization at the “scanned” position. With the purpose of using derivatives not only for scanning but also as a starting point for
Intramolecular 1,3-Dipolar Cycloaddition to Ester Carbonyl of Azomethinylides Prepared from Aldimines and Difluorocarbene
作者:I. V. Voznyi、M. S. Novikov、A. F. Khlebnikov、J. Kopf、R. R. Kostikov
DOI:10.1023/b:rujo.0000034942.42778.e0
日期:2004.2
Azomethinylides generated by reaction of difluorocarbene with N-alkyl- and N-arylimines of O-acylated salycilaldehyde undergo intramolecular 1,3-dipolar cycloaddition to the ester carbonyl group forming regioselectively 2,5-epoxy-1,4-benzoxazepine derivatives.
Convenient Synthesis of 3-Vinyl and 3-Styryl Coumarins
作者:Joana Gordo、João Avó、A. Jorge Parola、João C. Lima、António Pereira、Paula S. Branco
DOI:10.1021/ol201983u
日期:2011.10.7
A variety of 2-hydroxy aldehydes on reaction with 3-butenoic acid afford in a one-pot reaction the corresponding 3-vinylcoumarins. As expected, extension of the delocalized pi-electron system accomplished by Heck coupling reactions with aryl halides results in an increased fluorescence of the compounds whose applicability is yet to be established.