Chlorosulfonic acid → 129949-97-9

Participants

Reaction Steps

Crystals of phosphorus pentachloride (9.80 g., 47.1 mmoles) were added in portions to chlorosulfonic acid (9 ml., 15.4 g., 132 mmoles) in an inert atmosphere. The solution was stirred for 15 minutes. To this solution small portions of methyl thieno[2,3-b]thiophene-2-carboxylate (8.49 g., 42.8 mmoles) were slowly added, allowing for subsiding of effervescence between additions. After the addition was complete, the solution was stirred in an inert atmosphere for 25 minutes. The resulting solution was poured carefully onto ice-water. The resulting mixture was triturated and the off-white crystals were collected and washed with water and dried in vacuo over phosphorus pentoxide to give 11.58 g of 5-methoxycarbonylthieno[2,3-b]thiophene-2-sulfonylchloride. This was used in the next step without purification.

Provenance & Evidence