Ethyl 3,6-dihydro-5-mercapto-2H-pyran-4-carboxylate → HCID 22026130, compound

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Reaction Steps

Sodium perborate tetrahydrate (24.5 g) was added to acetic acid (130 ml) and the mixture was heated to 50–55° C. Thereto was added dropwise a solution of ethyl 5-sulfanyl-3,6-dihydro-2H-pyran-4-carboxylate (10.0 g) in acetic acid (30 ml) over 2 h. The mixture was stirred at 50–55° C. for 3 h, and the reaction mixture was concentrated under reduced pressure. To the residue was added acetonitrile (230 ml) and the mixture was stirred at room temperature for 2 days, and the resultant insoluble material was removed off by filtration and washed with acetonitrile (70 ml). The filtrate and washing were combined and the mixture was concentrated under reduced pressure. The residue was dissolved in acetonitrile (160 ml) and the mixture was stirred at room temperature for 6 h. The obtained insoluble material was removed off by filtration, and the filtrate was concentrated under reduced pressure. To the residue was added diisopropyl ether (100 ml), and the precipitated insoluble material was filtered off to give 4-(ethoxycarbonyl)-5,6-dihydro-2H-pyran-3-sulfonic acid as a pale-yellow oil (27.6 g) containing an inorganic product.

Provenance & Evidence