The general procedure for synthesizing 2-bromo-4-cyanothiazole using 2-bromothiazole-4-carboxamide as starting material is as follows: General method: after completing the preparation of the amide intermediate (Example A), the state of the reaction vessel is determined according to the boiling point of the amide intermediate. If the boiling point of the amide intermediate at atmospheric pressure is equal to or lower than the set reaction temperature (TB), the reaction vessel is closed; if the boiling point is higher than the TB, the reaction vessel is kept open. Subsequently, stirring is continued at a rate of 600 rpm and the reaction temperature is adjusted to TB. this temperature (TB) is maintained for a continuous period of TD hours until the reaction is nearly complete. Next, the reaction vessel was sealed and connected to a vacuum pump, the vacuum in the reaction vessel was adjusted to 20-50 mbar (depending on the nature of the nitrile product) and the distillate was collected as the nitrile product. The yield of the nitrile product was calculated, and samples were taken for NMR spectroscopy and elemental analysis to characterize the resulting nitrile product. The specific reaction conditions and characterization results are detailed in Tables A-7, A-8, A-9, A-10 and A-11. The characterization results showed that the obtained nitrile product was of very high purity (>99%). In some embodiments of the preparation of the nitrile product, 10 g of phosphorus pentoxide can be selectively added as a catalyst at the initial stage of the reaction.
