A thiazole compound, typically, 2-chloro-5-(aminomethyl)thiazole, of formula (3):
wherein X1 represents a hydrogen atom or a halogen atom, is a useful compound as an intermediate for pharmaceuticals and agrochemicals (see, e.g., JP 7-14916 B). For preparing the thiazole compound, several processes have been known. For example, (a) a compound of formula (1):
wherein X1 is as defined above, and X2 represents a halogen atom, is reacted with hexamethylenetetramine, followed by hydrolysis (see, e.g., JP 4-234864 A and JP 4-21674 A); (b) the compound of formula (1) is reacted with potassium phthalimide, followed by hydrazinolysis (see, e.g., JP 4-234864 A); (c) the compound of formula (1) is reacted with formamide, followed by hydrolysis (see, e.g., JP 5-286936 A); and (d) the compound of formula (1) is reacted with ammonia (see, e.g., JP 4-234864 A and JP 2000-143648 A).
However, the above processes (a) to (c) are not necessarily satisfactory from an industrial point of view because yields of the target thiazole compound of formula (3) are low in these processes. Although the above process (d) has an advantage over the processes (a) to (c) because of the use of low-priced ammonia, a considerable amount of a by-product compound of formula (4):
wherein X1 is as defined above, is formed even when using ammonia in 20 mol-fold amount or more relative to the compound of formula (1), which results in a low yield of the target thiazole compound of formula (3). Therefore, further improvement has been desired.