3-chloro-5-(3-n-hexylthien-2-yl)-4H-1,2,6-thiadiazin-4-one

Stille coupling of 5-chloro-4-oxo-4H-1,2,6-thiadiazin-3-yl trifluoromethanesulfonate (7) with tributyl(3-n-hexylthien-2-yl)stannane and Pd(Ph 3 P) 2 Cl 2 in PhMe at ca. 20 ◦ C, for 24 h gave 3-chloro-5-(3-n-hexylthien-2-yl)-4H-1,2,6-thiadiazin-4-one (9) with a 60% yield. The latter is a potentially useful building block for the synthesis of oligomeric and polymeric donors for organic photovoltaics.