Sulfur Dioxide → HCID 23046970, compound

Participants

Reaction Steps

10.9 g (0.04 mol) of 3-amino-2-methoxycarbonyl-4-phenylthiophene are dissolved in 20 ml of concentrated hydrochloric acid and then diazotised at -5° C. with 3.65 g of sodium nitrite in 10 ml of water. 30 minutes after the dropwise addition of sodium nitrite, the solution of the diazonium salt is added in portions to a mixture of 20 ml of dichloroethane, 0.45 g of benzyltriethylammonium chloride, 0.3 g of copper(I) chloride, 0.3 g of copper(II) chloride and 6 g of sulfur dioxide. When the addition at 5°-10° C. of the solution of the diazonium salt is complete, the reaction mixture is stirred for 1 hour at room temperature and then extracted three times with dichloroethane. The combined extracts are treated with activated carbon, filtered and concentrated. The resultant 2-methoxycarbonyl-4-phenylthiophen-3-ylsulfonyl chloride can be used further in the following reaction step without purification.

Provenance & Evidence