The reaction of imines with alkynes and alkenes, in the presence of 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ), to give quinoline derivatives is described. The mechanism of the annulation is discussed, and evidence supporting a non-concerted pathway, at least when the alkene is butyl vinyl ether, is reported. Preliminary information is also given about solid adducts of imines with DDQ, which do
The present invention relates to a process for preparing 2-aminobiphenyls of the formula I
in which
n is 0, 1, 2 or 3,
R
1
is hydrogen, cyano or fluorine, and
each R
2
is independently selected from cyano, fluorine, C
1
-C
4
-alkyl, C
1
-C
4
-fluoroalkyl, C
1
-C
4
-alkoxy, C
1
-C
4
-fluoroalkoxy, C
1
-C
4
-alkylthio and C
1
-C
4
-fluoroalkylthio.
The invention also relates to a process for preparing pyrazolecarboxamides of such 2-aminobiphenyls.
A Convenient Synthetic Access
to δ-Amino-γ,γ-difluoro-β-ketoesters
作者:Shizheng Zhu、Yanli Wang
DOI:10.1055/s-2002-33905
日期:——
The zinc-cuprous chloride promoted Reformatsky-imine addition reaction of 4-bromo-4,4-difluoroacetoacetate with aldimines derived from aromatic aldehydes and with ketimines derived from aryl alkyl ketone provided an efficient and practical access to δ-amino-γ,γ-difluoro-β-ketoesters. The scope and limitation of this procedure are also discussed.
β-Amino esters via the Reformatsky reaction: Restraining effects of the ortho-methoxyphenyl substituent
作者:James C. Adrian、Julia L. Barkin、Lamyaa Hassib
DOI:10.1016/s0040-4039(99)00248-8
日期:1999.3
β-Amino esters are, in most cases, the only products of the Reformatskyreaction in CH2Cl2 between (methoxycarbonyl)methyl zinc bromide (prepared in-situ) and imines prepared from either an aryl or alkyl aldehyde and o-anisdine (Scheme 2). Restraining properties of the ortho-methoxyphenyl group, which lead to sole formation of the β-amino ester, are ascribed to the inductive effect of the ortho-methoxy