Synthesis of 1,3-Oxazoles via Van Leusen Reaction in a Pressure Reactor and Preliminary Studies of Cations Recognition

Verónica G García-Ramírez,Luis Chacón-García,Gabriela Rodriguez-García,Claudia Contreras-Celedón,Carlos J Cortes-García

doi:10.3390/ecsoc-23-06463

Verónica G García-Ramírez, Luis Chacón-García + Show 3 more

Open Access

https://doi.org/10.3390/ecsoc-23-06463

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Publication Date: Dec 31, 2019
Citations: 1	License type: CC BY 4.0

Affiliation: Universidad Michoacana de San Nicolás de Hidalgo

Abstract

Six 1,3-oxazoles were synthetized in moderate to good yields by Van Leusen reaction in a pressure reactor. The methodology allowed to decrease the reaction times reported in the literature from hours to 20 min. In addition, preliminary qualitative recognition of cations with some synthetized oxazoles such as Hg2+, Ni2+, Zn2+, Ag+, Cu2+, Pb2+ was done and a “turn off” effect was observed with Ni2+. Finally, the 1,3-oxazoles could be of biological relevance because they are considered privileged nucleus in medicinal chemistry and therefore will be useful to obtain pharmacophoric hybrid molecules.

Highlights

Six 1,3-oxazoles were synthetized in moderate to good yields by Van Leusen reaction in a pressure reactor
The 1,3-oxazoles 9a–f were synthetized in moderate to good yields via Van Leusen reaction according to the Scheme 1 by using p-Toluenesulfonylmethyl isocyanide 8 (TosMIC) and different complex aldehydes 7 such as 4-(2-pyridyl)benzaldehyde which is a principal fragment of HIV drug
The strength of this work relies on using a pressure reactor to accelerate Van Leusen reaction since this reaction take hours to complete and by using our methodology take only 20 min. the 1,3oxazoles synthetized are shown in the Table 1

Summary

Introduction

Six 1,3-oxazoles were synthetized in moderate to good yields by Van Leusen reaction in a pressure reactor. Preliminary qualitative recognition of cations with some synthetized oxazoles such as Hg2+, Ni2+, Zn2+, Ag+, Cu2+, Pb2+ was done and a “turn off” effect was observed with Ni2+. In this work the synthesis of six 1,3-oxazoles derivates via Van Leusen reaction is described, allowing moderate to good yields at 20 min in reaction time by using a pressure reactor as simplistic strategy, thereby, compatibility of the employed reaction conditions with Van Leusen reaction. The best of knowledge, there is no literature reports about the use of pressure reactor in this kind of reaction, an improvement of the methodology is described. Preliminary assays of cation recognition of oxazole 9b by naked-eye was done and a “turn off” effect was observed with Ni2+. Fluorescent changes by naked-eye by variating pH was done and increasing of fluorescence was observed in acid medium

Methods

Results

Conclusion