5,10-bis((2-ethylhexyl)oxy)dithieno[2,3-d:2',3'-d']benzo[1,2-b:4,5-b']dithiophene synthesis

Yield:1446476-78-3 1.3 g

Reaction Conditions:

Stage #1: dithieno[2,3-d:2′,3′-d′]benzo[1,2-b:4,5-b′]dithiophene-5,10-dionewith sodium hydroxide;zinc in water; for 0.5 h;Reflux;
Stage #2: 3-bromomethylheptanewith tetrabutylammomium bromide in ethanol;water;Reflux;

Steps:

2.5. 4,8-Bis(2-ethylhexyloxy)benzo[1,2-b:4,5-b0]dithieno[3,2-b]thiophene (4)

Compound 3 (1.5 g, 4.5 mmol), Zn powder (0.70 g, 11 mmol) andNaOH (3 g) were charged into a 100-mL single neck flask, afteraddingwater, the solutionwas heated up to reflux for 30 min. Then,the 2-ethylhexyl bromide (3 mL, 15.6 mmol) and tetrabutylaminoumbromide (0.5 g, 1.55 mmol) were added into the flask. Theresulted solution was refluxed overnight. The mixture was pouredinto water and extracted with dichloromethane (200 mL), driedover anhydrous Na2SO4. After removing the solvent, the crudeproduct was purified through silica column using hexane anddichloromethane as eluent to give the yellow oil (1.3 g, 52%). 1HNMR (CDCl3, ppm): 7.58 (d, J 5.20 Hz, 2H), 7.36 (d, J 5.20 Hz,2H), 4.26 (d, J 6.18 Hz, 4H), 2.09e2.05 (m, 2H),1.46e1.28 (m,16H),1.10-0.93 (m, 12H). 13C NMR (CDCl3, ppm): 143.83, 142.28, 139.65,134.44,129.30,120.65, 74.05, 40.10, 32.98, 30.33, 27.69, 23.46,14.63,11.05. HRMS (ESI) (M+, C30H38O2S4): calcd, 558.1755; found,558.1743.

References:

Lang, Caili;Fan, Jingzhe;Gao, Yueyue;Liu, Ming;Zhang, Yong;Guo, Fengyun;Zhao, Liancheng [Dyes and Pigments,2017,vol. 137,p. 50 - 57]