A Hantzsch synthesis of 2-aminothiazoles performed in a heated microreactor system
Abstract
This paper presents the first example known to the authors of a heated organic reaction performed on a glass microreactor under electro-osmotic flow control. The experiments consisted of the preparation of a series of 2-aminothiazoles by means of a Hantzsch reaction of ring-substituted 2-bromoacetophenones and 1-substituted-2-thioureas carried out in microchannels, with the aim of investigating the generic utility of the reactor in carrying out analogue reactions. The reactions were performed on T-design microchips etched into a thin borosilicate glass plate and sealed over with a thick borosilicate top plate containing reservoirs. The mobility of the reagents and products was achieved using electro-osmotic flow (EOF), with the driving voltages being generated by a computer-controlled power supply. During the experiments the T-shaped chip was heated at 70 °C using a Peltier heater, aligned with the channels and the heat generated by this device was applied to the lower plate.
The degree of conversion was quantified by