Selenazoles thiazoles, similarity

In a comparison of the chemical properties of thiazoles and the selenazoles thus known, Ochiai concluded that they are mutually very similar. In addition, the evaluation of later experiments shows that only small differences exist between the reactivity of thiazoles and the corresponding selenazoles. 

A selection of cyclizations of 2-amino-3-substituted thiazoles, leading to the formation of imidazo[2,l-i]thiazoles, is shown in Equations (32)-(35). Cyclization of the phenacylthiazolium salt (106) or the alcohol (108), obtained from (106) by sodium borohydride reduction, afforded (107) or (109), respectively <94EJM309>. The cyclization of (110) provided one of the earliest syntheses of the anthelmintic drug tetramisole (34) <68JOC1350> and the corresponding imidazo[2,1 -ft]selenazole (112) was prepared from (111) in a similar manner <78JMC496>. 

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