Tetrabutylammonium Bromide-Catalyzed Transfer Hydrogenation of Quinoxaline with HBpin as a Hydrogen Source
作者:Qi Guo、Jingchao Chen、Guoli Shen、Guangfu Lu、Xuemei Yang、Yan Tang、Yuanbin Zhu、Shiyuan Wu、Baomin Fan
DOI:10.1021/acs.joc.1c02537
日期:2022.1.7
A metal-free environmentally benign, simple, and efficient transfer hydrogenation process of quinoxaline has been developed using the HBpin reagent as a hydrogen source. This reaction is compatible with a variety of quinoxalines offering the desired tetrahydroquinoxalines in moderate-to-excellent yields with Bu4NBr as a noncorrosive and low-cost catalyst.
2,4-Diaminopyrimidine compounds useful as immunosuppressants
申请人:——
公开号:US20030191307A1
公开(公告)日:2003-10-09
Novel compounds according to the formula
1
and pharmaceutically acceptable salts, solvates, or hydrates thereof; wherein
each occurrence of A is independently selected from CH or N;
X is selected from the group consisting of —CH
2
—, —O—, —NH—, (C
1
-C
6
)alkylamino-, (C
1
-C
6
)alkylaminocarbonylamino-, (C
1
-C
6
)alkylcarbonylamino-, (C
1
-C
6
)alkylsulfonylamino-, phenylsulfonylamino-, carbonyl, —NH—C(O)—, —N(C
1
-C
6
)alkyl-C(O)—, —S(O)
y
— where y is 0, 1 or 2, and;
n in —(CH
2
)
n
— is 1, 2 or 3; and
R
1
, R
2
, and R
3
are as described herein; pharmaceutical compositions that including these compounds, and methods for the treatment of autoimmune disease, inflammation, allergy, transplant rejection, and other circumstances where administration of an immunosuppressive agent is of therapeutic benefit.
Metal‐Free Hydrogenation of
<i>N</i>
‐Heterocycles with Trimethylamine Borane and TFA in Aqueous Solution
作者:Yao‐Fu Zeng、Yi‐Na Li、Ming‐Xi Zhou、Shuai Han、Yu Guo、Zhen Wang
DOI:10.1002/adsc.202200795
日期:2022.11.8
A metal-freehydrogenation of quinoxalines and indoles with Me3N ⋅ BH3 and TFA in water at room temperature is reported. The protocol is featured with the usage of environmentally friendly water as the solvent, no need of metal catalyst and broad substrate scope. Sensitive functional groups such as OH-, NH2-, Cl-, Br-, especially -CN and -CO2Me were well tolerated. Preliminary mechanistic studies suggested
报道了在室温下在水中用 Me 3 N · BH 3和 TFA对喹喔啉和吲哚进行无金属氢化反应。该方案的特点是使用环保水作为溶剂,无需金属催化剂,底物范围广。敏感官能团如OH-、NH 2 -、Cl-、Br-,尤其是-CN 和-CO 2 Me 具有良好的耐受性。初步机理研究表明,TFA 和 Me 3 N·BH 3分别为产品提供了质子和氢化物来源。
Efficient reduction of quinoxaline compounds using zinc chloride—sodium borohydride system
Reagent system NaBH4—ZnCl2 was found to be suitable for the reduction of various substituted quinoxalines to obtain corresponding 1,2,3,4-tetrahydro derivatives. The reduction proceeds quickly under mild reaction conditions. The procedure is convenient and can be applied for a wide scope of substrates.
The search for efficient molecular hydrogenprecursors and their catalytic exploration is necessary for the evolution of catalytic transfer hydrogenation. Methyl formate (MF) having high hydrogen content still remains unexplored for such transformations. Herein, we disclosed a bifunctional Ir(III)-complex catalyzed chemoselective TH protocol for N-heteroarenes and azoarenes using MF. A variety of substrates