Facile synthesis of benzoxazoles from 1,1-dibromoethenes
摘要:
Direct coupling of 1,1-dibromoethenes with 2-aminophenols had been achieved to form the corresponding benzoxazoles under mildly basic reaction conditions. A variety of substituted 2-aminophenols provided the desired products in moderate to good yields. Even though 1,1-dibromoethenes have to be derived from arylcarboxaldehydes or glyoxalate for the reactions, this method still provides a new route to the preparation of benzoxazoles, complementing to existing synthetic strategies. (C) 2010 Elsevier Ltd. All rights reserved.
Elemental Sulfur-Promoted Oxidative Rearranging Coupling between o-Aminophenols and Ketones: A Synthesis of 2-Alkyl benzoxazoles under Mild Conditions
作者:Thanh Binh Nguyen、Pascal Retailleau
DOI:10.1021/acs.orglett.7b01775
日期:2017.7.21
In the presence of N-methylpiperidine, elemental sulfur was found to act as excellent oxidant in promoting oxidative rearranging coupling between o-aminophenols and ketones. A wide range of 2-alkylbenzoxazoles was obtained under mild conditions.
Rhodium-catalyzed synthesis of unsymmetrical di(aryl/heteroaryl)methanes using aryl/heteroarylmethyl ketones via CO–C bond cleavage
作者:Guangzhe Li、Mieko Arisawa、Masahiko Yamaguchi
DOI:10.1039/c4cc00816b
日期:——
RhH(PPh3)4 and 1,2-bis(diphenylphosphino)benzene catalyze the reaction of aryl/heteroarylmethyl ketones and arylheteroaryl ethers giving unsymmetrical diarylmethanes containing one or two heteroarenes in high yields. The reaction does not use alkali metal bases, and therefore does not form large amounts of metal waste.
The direct CH benzylation of azoles with benzyl chlorides proceeds efficiently, via sequential cleavage of one sp2 CH bond and two sp3 CHbonds in the presence of a palladium catalyst, to generate a wide range of tribenzylated azoles with a quaternary carboncenter efficiently. The same catalyst could also promote the mono‐ and di‐benzylation reactions through fine turning of the base and reaction
An elegant and catalytic procedure for the one-step cyanomethylenation of C(sp3)–H bonds adjacent to benzazoles and ketones is described herein using DMF as a C-1 unit and TMSCN as the cyanide source. The copper-mediated reaction between DMF and TMSCN gives a cyanomethylene radical intermediate that reacts with 2-alkylbenzazoles or alkylketones to furnish desired cyanomethylenated compounds under palladium
[Problems] To provide a compound that is useful as an agent for treating chronic renal insufficiency or an agent for treating diabetic nephropathy.
[Means for Solving Problems] The present inventors have conducted extensive studies on a compound having an EP4 receptor antagonistic action, and as a result, they have found that various amide derivatives having a carboxylic group or an equivalent thereof exhibit an excellent EP4 receptor antagonistic action, thereby completing the present invention.
Since the compound of the present invention has an excellent EP4 receptor antagonistic action, it is useful as an agent for preventing and/or treating chronic renal insufficiency or diabetic nephropathy.