Enaminones can be prepared via the Rh2(OAc)4-catalyzed coupling of α-diazocarbonyl compounds with thioamides. However, rhodium is the most expensive and least abundant among the dominant precious metals used for catalysis. Furthermore, a very limited substrate scope is known for the intermolecular rhodium catalyzed coupling reaction. Therefore, there is a need to find a more economical catalyst substitute with a broad substrate scope. In this paper, we describe the use of Ru(II) catalysts for the synthesis of enaminones. The reaction can be performed efficiently with the Grubbs first-generation catalyst or [(Ph)3P]3RuCl2 in a sealed tube. Both catalysts are much less expensive than Rh2(OAc)4. Secondary and tertiary thioamides, when reacted with α-diazodiesters, α-diazoketoesters, α-diazodiketones, and α-diazomonoketones give enaminones. Primary thioamides give thiazole derivatives when reacted with α-diazomonoketones. However, with other diazo compounds, primary thioamides also give enaminones. All enaminones are obtained in good yields and with good diastereoselectivity. Accordingly, the method described in this paper is an efficient and economical alternative to the Rh2(OAc)4-catalyzed coupling process.
Students in a large introductory organic chemistry class were given the freedom to choose an organic compound of interest and were challenged to develop an educational object (physical or digital) designed to be shared with the broader publicviasocial media. Analysis of the project results shows that most students appreciated the open nature of the assignment, and engaged in self-regulated learning by reflecting and improving on their educational object design along each step of the project. Subjects varied widely depending on the students’ personal interests, and many different educational objects were produced and shared using diverse social media outlets. As a result of this project, students reported positive outcomes including increased interest in organic chemistry and science in general as well as the acquisition of practical skills such as science communication and visual representation of science. These skills were perceived by students as being beneficial for future professional endeavors. This report describes the design and outcomes of the project, including the choice of subjects, representations, and social media channels.
Chloride, bromide and iodide are inhibitors of the copper-catalysed azide-alkyne cycloaddition, with iodide exhibiting the most detrimental effects on rates and yields. A study of this inhibition is presented, along with experimental protocols to accommodate the presence of halides in this widely used reaction.
The failure of frontline antibiotics in the clinic is one of the most serious threats to human health and requires a multitude of novel therapeutics and innovative approaches to treatment so as to curtail the growing crisis. In addition to traditional resistance mechanisms resulting in the lack of efficacy of many antibiotics, most chronic and recurring infections are further made tolerant to antibiotic action by the presence of biofilms. Herein, we report an expanded set of 5‐benzylidene‐4‐oxazolidinones that are able to inhibit the formation of Staphylococcus aureus biofilms, disperse preformed biofilms, and, in combination with common antibiotics, are able to significantly reduce the bacterial load in a robust collagen‐matrix model of biofilm infection.
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