Lithium → HCID 15158734, compound

Participants

Reaction Steps

To a solution of the mixture obtained in Step 2 (100 g) in anhydrous ether (440 ml) was added dropwise 1.5 M lithium diisopropylnmide mono(tetrahydrofuran) in cyclohexane (440 ml) under nitrogen atmosphere at -70° C. over 1 hour, then into the solution was bubbled sulfur dioxide for 1.5 hours at -70° C. After stirring for 1 hour at room temperature, the solvent was removed in vacuo and ether was added to the residue. The formed precipitate was separated by filtration to give a mixture of lithium 4,5-dichlorobenzo[b]furan-2-sulfinate and lithium 5,6-dichlorobenzo[b]furan-2-sulfinate. To the suspension of the products in dichloromethane (1.8 l) was added N-chlorosuccimimide (92.1 g) at -50° C. and stirred for 1.5 hours. At room temperature, insoluble matters were filtered off and dichloromethane was removed in vacuo and the residue was purified by silica gel column chromatography to give 17.4 g of 4,5-dichlorobenzo[b]furan-2-ylsulfonyl chloride and 7.4 g of 5,6-dichlorobenzo[b]furan-2-ylsulfonyl chloride, respectively. 4,5-dichlorobenzo[b]furan-2-ylsulfonyl chloride

Provenance & Evidence