Synergistic Indium and Silver Dual Catalysis: A Regioselective [2 + 2 + 1]-Oxidative <i>N</i>-Annulation Approach for the Diverse and Polyfunctionalized <i>N</i>-Arylpyrazoles
作者:Raju S. Thombal、Yong Rok Lee
DOI:10.1021/acs.orglett.8b02008
日期:2018.8.3
Indium(III)/silver(I)-catalyzed [2 + 2 + 1] annulation of arylhydrazine hydrochlorides with β-enamino esters via multicomponent reactions for the construction of diverse and multisubstituted N-arylpyrazoles has been demonstrated. The oxidative cycloaddition proceeds via a cascade triple Michael addition/elimination/air oxidation. This novel protocol provides a rapid and efficient synthetic route to
A direct and regiocontrolled thiolation method to access β-amino sulfides through the palladium-catalyzed C(sp2)–H functionalization of stable enamines was described. The reaction was realized under mild conditions by adding an external phosphine ligand to prevent poisoning of the palladium catalyst by the sulfuric reagents. A possible mechanism was proposed according to the obtained results. The DFT
描述了一种通过钯催化的稳定烯胺的 C(sp2)-H 官能化获得 β-氨基硫化物的直接和区域控制的硫醇化方法。该反应在温和条件下通过添加外部膦配体来实现,以防止钯催化剂被硫酸试剂中毒。根据所得结果提出了一种可能的机制。DFT 计算结果与实验数据一致,给出了 β-氨基硫化物的 E 异构体。该反应也以克规模进行,并显示出在有机合成中的潜在应用。
Regioselective construction of diverse and multifunctionalized 2-hydroxybenzophenones for sun protection by indium(<scp>iii</scp>)-catalyzed benzannulation
作者:Hongyun Cai、Likai Xia、Yong Rok Lee
DOI:10.1039/c6cc02381a
日期:——
Highly regioselective synthesis of 2-hydroxybenzophenones via the In(OTf)3-catalyzed formal [2+2+2] and [4+2] benzannulations has been successfully developed and their application as sun protection materials was also evaluated.
Method for the Production of Halogen-Substituted 2-(aminomethylidene)-3-oxobutyric Acid Esters
申请人:Zierke Thomas
公开号:US20110040096A1
公开(公告)日:2011-02-17
The present invention relates to a process for preparing 2-(aminomethylidene)-4,4-dihalo-3-oxobutyric esters of the formula (I),
wherein R
1
, R
2
, R
3
are C
1
-C
6
-alkyl, C
1
-C
6
-haloalkyl, C
2
-C
6
-alkenyl, C
3
-C
10
-cycloalkyl or benzyl, and/or R
2
together with R
3
and the nitrogen atom to which the two radicals are attached are a heterocyclic radical, in which a corresponding 3-aminoacrylic ester is reacted with a halogen-substituted acetyl fluoride in the presence of at least one alkali or alkaline earth metal fluoride; and the further conversion of halogen-substituted 2-(aminomethylidene)-3-oxobutyric esters of the formula (I) to halomethyl-substituted pyrazol-4-ylcarboxylic acids and their esters.
PROCESS FOR PREPARING 2-(AMINOMETHYLIDENE)-4,4-DIFLUORO-3-OXOBUTYRIC ESTERS
申请人:Zierke Thomas
公开号:US20110046371A1
公开(公告)日:2011-02-24
The present invention relates to a process for preparing difluoromethyl-substituted pyrazol-4-ylcarboxylic acids and their esters, 2-(aminomethylidene)-4,4-difluoro-3-oxobutteric esters of the formula (I)
in which R
1
, R
2
and R
3
independently of one another are C
1
-C
6
-alkyl, C
1
-C
6
-haloalkyl, C
2
-C
6
-alkenyl, C
3
-C
10
-cycloalkyl or benzyl or NR
2
R
3
is a 5- to 10-membered heterocyclic radical, to a process for preparing compounds of the formula (I) wherein an appropriate 3-aminoacrylic ester is reacted with difluoroacetyl fluoride and to the use of compounds of the formula (I) in the process for preparing difluoromethyl-substituted pyrazol-4-ylcarboxylic acids and their esters.