Scheme 3.
Isothiourionium Salt Based-synthesis of Thioethers a
aReagent and conditions: (i): NaOEt, MeOH, rt, no reaction; (ii) THF, TEA, 6 h, rt, no reaction; (iii) CS(NH2)2, EtOH, 4 h, reflux, 12a (83%), 12b (80%), 12c (52 %), 12d (71%); (iv) 12a -12d, Cs2CO3, DMF, 16 h, 85 °C, 13a (28%), 13b (56%), 13c (77%), 13d (49%).