Alternative synthetic routes to N-methyl-1,2,4-triazoline-3,5-dione (MeTAD) and other triazolinedione derivatives
摘要:
N-Methyl-1,2,4-triazoline-3,5-dione (MeTAD) is a powerful electrophile and a versatile synthetic reagent. In this Letter we describe two methods for the synthesis of N-methylurazole, the direct precursor to MeTAD, on gram scales and in good yields. Both methods provide pure urazole while avoiding the necessity of large scale purification via column chromatography or recrystallization. One of the methods proved to be amenable for the synthesis of derivatives other than N-methyl. (C) 2014 Elsevier Ltd. All rights reserved.
Telescoped Oxidation and Cycloaddition of Urazoles to Access Diazacyclobutenes
作者:Brock A. Miller、Chandima J. Narangoda、Thomas L. Johnson、Ryan D. Barata、Flavoris Belue、Erin E. Solomon、Alexis A. Bragg、Daniel C. Whitehead
DOI:10.1021/acs.joc.2c00280
日期:2022.6.3
previous method to access the diazacyclobutene scaffold did not allow for modification of the substituent originating from the 1,2,4-triazoline-3,5-dione component. We have circumvented this challenge and expanded access to additional structural diversity of the scaffold. A telescoped urazole oxidation and Lewis acid-catalyzed cyclization provided R3-substituted diazacyclobutenes. Calcium hypochlorite-mediated
我们以前访问二氮杂环丁烯支架的方法不允许修改源自 1,2,4-三唑啉-3,5-二酮成分的取代基。我们已经规避了这一挑战,并扩大了对脚手架额外结构多样性的访问。伸缩的乌拉唑氧化和路易斯酸催化的环化提供了 R 3取代的二氮杂环丁烯。次氯酸钙介导的乌拉唑氧化,随后 MgCl 2催化所得三唑啉二酮与硫代炔烃的环化促进了二氮杂环丁烯的形成,该二氮杂环丁烯在源自三唑啉二酮组分的R 3位置带有取代。
An Improved Synthesis of 1,2,4-Triazoline-3,5-diones