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.
Water-compatible Cascade Reaction: An Efficient Route to Substituted 2,3-Dihydrofurans
作者:Ya-Ru Zhang、Fang Luo、Xu-Jiao Huang、Jian-Wu Xie
DOI:10.1246/cl.2012.777
日期:2012.8.5
A highly efficient domino Michael addition–alkylation reaction of 1,3-dicarbonyl derivatives with 2-nitroacrylates was developed in water. The procedure tolerates a series of functional groups such as methoxy, bromo, chloro, and heteroaromatic groups, providing three types of 2,3-dihydrofuran derivatives in moderate to good yields.
New purine retinoid compounds according to the formula: ##STR1## wherein R is a purine derivative, and pharmaceutical compositions thereof, are provided which exhibit cancer-inhibiting activity.
A novel chiral metal‐organic framework (MOF) organocatalyst has been developed, based on readily available MIL‐101 and the chiral primary diamine (1R,2R)‐1,2‐diphenylethylenediamine, by the post‐synthetic modification. Over the developed chiral heterogeneous catalyst the asymmetric synthesis of (S)‐warfarin with high enantioselectivity can be fulfilled on a gram‐scale (2.8 g) with excellent yield (92%)
A facile in situ formed primary amine-imine organocatalyst was developed in the asymmetric Michael addition of substituted 4-hydroxycoumarins to cyclic enones. A series of optically active polycyclic coumarinderivatives were obtained in high yields with excellent enantioselectivities up to 97% ee.
Regioselective Synthesis of 4,5-Dihydro-6<i>H</i>
-oxepino[3,2-<i>c</i>
]chromene-2,6(3<i>H</i>
)-diones through Palladium-Catalyzed Intramolecular Alkoxycarbonylation of 3-Allyl-4-hydroxycoumarins
作者:D. Oliver Sosa、Karla Almaraz、Manuel Amézquita-Valencia
DOI:10.1002/ejoc.201900649
日期:2019.8.7
This work presents a regioselective route to synthesize seven‐membered ring lactones fused to coumarin scaffold in good yields and high regioselectivity. Additionality, the carbonylation reaction does not require acidic conditions and proceeds in the absence of any other additive such as hydrogen (H2).