Thionyl Chloride → HCID 18551622, compound

Participants

Reaction Steps

2-mercaptobenzthiazol (83.4 g, 0.5 mol) was dispersed in 100 mL of methanol, and added a solution containing 24 g of NaOH in 50 mL of H2O. When 2-mercaptobenzthiazol was completely dissolved, n-butylbromide (54 mL, 0.5 mol) was added and the reaction solution was refluxed for 12 hours. Then, methanol was removed from the solution under reduced pressure and 300 mL of ethylacetate was added to the solution which was then washed with H2O and 1M K2CO3 in a sequential order. The separated organic solution was dried over MgSO4 and then distilled under reduced pressure to give about 100 g of pure 2-n-butylthio-6-benzthiazol (89%), which was subsequentially transferred to a flask of 500 mL without further purification and cooled down to a temperature of 0° C. Chlorosulfonic acid (130 g, 2.5 equi.) was slowly added into the flask. The reaction solution was reacted for 24 hours at about 110° C. When starting material was completely exhausted, the reaction solution was cooled down to room temperature (RT) and stirred vigorously after adding ice water. Then, the solid product was obtained by filtering. The filtered solid was treated with ethylacetate (300 mL) followed by stirring for 1 hour. The undissolved solid was filtered and washed with ethylacetate to give 2-n-butylthio-6-benzthiazolsulfonic acid (30 g). The filtrated ethylacetate solution was treated with 5 g of activated carbon and MgSO4 and stirred for 1 hour. Then, the ethylacetate solution was filtered on activated carbon and MgSO4 again and dried under reduced pressure to remove the solvent, to give the titled compound, 2-n-butylthio-6-benzthiazolsulfonyl chloride (about 60 g) in a solid form. The titled compound was treated with n-hexane (150 mL), followed by stirring for 1 hour. After filtering, pure 2-n-butylthio-6-benzthiazolsulfonyl chloride (55 g) was obtained. A 30 mL of SOCl2 as solvent and as reagent was added to 2-n-butylthio-6-benzthiazolsulfonic acid (30 g) obtained above. The reaction solution was refluxed for 5 hours, dried under reduced pressure, and then, treated with H2O. The solid product was obtained by filtering. The solid was stirred with ethylacetate (100 mL) for 1 hour. The ethylacetate solution was treated with 5 g of activated carbon and MgSO4 and stirred for 1 hour. The solution after filtering on activated carbon and MgSO4 was dried under reduced pressure to remove the solvent, to give the titled compound, 2-n-butylthio-6-benzthiazolsulfonyl chloride (about 30 g) in a solid form. The compound was purified with n-hexane as described above, to give a pure 2-n-butylthio-6-benzthiazolsulfonyl chloride (25 g). Consquently, about 80 g of titled compound (about 56%) was prepared by two processes.

Provenance & Evidence