3-ethyl-5-(2-hydroxyethyl)-4-methyl-1,3-thiazolium bromide; 1,8-diazabicyclo[5.4.0]undec-7-ene; isopropyl alcohol in tetrahydrofuran T=70°C; Sila-Stetter reaction;

hydrogenchloride; water

in benzene 2 h; Irradiation;