A Practical Approach to the Synthesis of 2,4-Disubstituted Oxazoles from Amino Acids
摘要:
[GRAPHICS]A new sequence for the synthesis of various 2,4-disubstituted oxazoles from alpha-amino acids is reported. The method is shown to be general and incorporates the reagent combination, triphenylphosphine/hexachloroethane, for cyclodehydration of intermediate alpha-acylamino aldehydes. Implementation of this reagent system for the conversion of alpha-acylamino ketones to oxazoles is briefly investigated.
A palladium‐catalyzed tandem reaction of cyanomethyl benzoates with arylboronic acids has been achieved. Substitution at the 2‐position of cyanomethyl benzoates was found to be crucial for the selective synthesis of oxazoles and isocoumarins. Cyanomethyl benzoates afforded 2,4‐diaryloxazoles as products, while 2‐benzoyl‐substituted cyanomethyl benzoates delivered 3‐benzoyl‐4‐aryl‐isocoumarins selectively
Synthesis of 2,4-Disubstituted Oxazoles by a Copper-Catalyzed [3+2] Annulation/Olefination Cascade between Amides and IIII/PV Hybrid Ylides
作者:Zhaofeng Wang、Xingchen Ye
DOI:10.1055/a-2185-0673
日期:——
We report a novel and efficient method for oxazole synthesis through a copper-catalyzed [3+2] annulation/olefination cascade between readily available iodonium–phosphonium hybrid ylides and amides. An unprecedented α-phosphonium Cu carbenoid acts as the key intermediate. This method features excellent regioselectivity with mild reaction conditions and a broad substrate scope. Its synthetic utility
Manganese‐catalyzed Dehydrogenation of Amido Alcohols with Liberation of Hydrogen for the Synthesis of Oxazoles
作者:Max Leinert、Torsten Irrgang、Rhett Kempe
DOI:10.1002/cctc.202301042
日期:2023.11.22
The synthesis of oxazoles from abundantly and diversely available and inexpensive starting materials such as esters and amino alcohols is reported. Our reaction proceeds via liberation of hydrogen and a molecular manganese catalyst mediates it most efficiently. All oxazole derivatives reported, except the screening substrate and an application, are novel compounds indicating the difficulties associated
Compositions and methods for controlling nematodes
申请人:Monsanto Technology LLC
公开号:US10375958B2
公开(公告)日:2019-08-13
Compositions and methods for controlling nematodes are described herein, e.g., nematodes that infest plants or animals. The compounds include oxazoles, oxadiazoles and thiadiazoles.
A novel synthetic method for the preparation of 2,4-disubstituted oxazoles was developed, entailing the reaction of dibutyltin diacylates Bu2Sn[OC(O)R](2) with 1-substituted acetylenes and TMSN3 to afford a range of 2,4-disubstituted oxazoles in good yields. (C) 2020 Elsevier Ltd. All rights reserved.