Synthesis
General procedure for the synthesis of 2,7-dichlorobenzo[d]thiazole from 7-chlorobenzo[d]thiazole-2(3H)-thione: General method: a mixture of 7-chlorobenzo[d]thiazole-2(3H)-thione (>1 g, 1 eq.) and sulfuryl chloride (10 eq.) was stirred at 20-25 °C for 15 min. Subsequently, water (2 eq.) was added and stirring was continued for 3 hours at 20-25 °C. During the reaction, the sample was removed, quenched with acetonitrile/water (2:1) and analyzed by high performance liquid chromatography (HPLC). Upon completion of the reaction, the mixture was diluted with acetonitrile (5 v/v) and the reaction was quenched by slowly adding water (20 v/v). The product precipitated from the aqueous solution and the solid was collected and washed with distilled water. Finally, the solid was dried under vacuum to give pure 2,7-dichlorobenzo[d]thiazole. For the liquid product 2-chlorobenzo[d]thiazole (13), the reaction mixture was extracted with ethyl acetate and the organic layer was dried and concentrated to give an oily product.
References
[1] Synthesis (Germany), 2018, vol. 50, # 10, p. 2027 - 2032
[2] Journal of Heterocyclic Chemistry, 2005, vol. 42, # 4, p. 727 - 730
[3] Gazzetta Chimica Italiana, 1965, vol. 95, p. 490 - 498
