Regioselective Synthesis of Chromeno[4,3‐c] isoquinolin‐11‐ones by Radical Cyclization
摘要:
A number of 4-tosyloxycoumarins were treated with N-methyl,N-(2-bromobenzyl)amine, and N-methyl,N-(2-bromo-5-methoxybenzyl)amine in refluxing ethanol to give different 4-[N-(2'-bromobenzy]),N-methyl] amino coumarins in 70-75% yield. These tertiary amine substrates were then refluxed in dry benzene under nitrogen with tri-n-butyltin chloride and sodium cyanoborohydride in the presence of 0.5-0.6 mol equiv. of azobisisobutyronitrile(AIBN) for 4-5 hr to give the title compounds in 65-68% yield.
Convenient Michael addition/β-elimination approach to the synthesis of 4-benzyl- and 4-aryl-selenyl coumarins using diselenides as selenium sources
作者:Gustavo Padilha、Paloma T. Birmann、Micaela Domingues、Teodoro S. Kaufman、Lucielli Savegnago、Claudio C. Silveira
DOI:10.1016/j.tetlet.2017.01.084
日期:2017.3
coumarin derivatives from the easily available 4-hydroxycoumarins, is reported. The synthesis was based on conventional tosylation followed by a tandem selena-Michael addition/β-elimination reaction of an aryl-/benzyl-selenolate anion on the corresponding 4-tosyloxycoumarins. The selenolate anions were conveniently generated in situ by exposure of the corresponding diselenides to NaBH4. Selected compounds
Regioselective Synthesis of Chromeno[4,3‐<i>c</i>] isoquinolin‐11‐ones by Radical Cyclization
作者:K. C. Majumdar、S. Sarkar
DOI:10.1081/scc-200026621
日期:2004.1.1
A number of 4-tosyloxycoumarins were treated with N-methyl,N-(2-bromobenzyl)amine, and N-methyl,N-(2-bromo-5-methoxybenzyl)amine in refluxing ethanol to give different 4-[N-(2'-bromobenzy]),N-methyl] amino coumarins in 70-75% yield. These tertiary amine substrates were then refluxed in dry benzene under nitrogen with tri-n-butyltin chloride and sodium cyanoborohydride in the presence of 0.5-0.6 mol equiv. of azobisisobutyronitrile(AIBN) for 4-5 hr to give the title compounds in 65-68% yield.