Cysteamine Hydrochloride → (1)Benzothieno(2,3-f)-1,4-thiazepin-5(2H)-one, 3,4-dihydro-9-methoxy-

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Reaction Steps

To a room temperature solution of methyl 3-chloromethoxy-benzo[b]thiophene-2-carboxylate (500 mg, 1.95 mmol) [prepared by reaction of the known 3-chloro-5-methoxy-benzo[b]thiophene-2-carbonyl chloride with methanol- [J. Med. Chem., 35:958 (1992)]] in 20 mL of DMF is added cysteamine-HCl (885 mg, 7.79 mmol) followed by DBU (2.33 mL, 15.58 mmol). The reaction mixture is stirred at room temperature for 1.5 hours then warmed to 70° C. The mixture is diluted with ethyl acetate and washed with aqueous HCl, water and brine. The organic layer is dried over MgSO4, filtered and concentrated in vacuo. The crude product is recrystallized from hexane and ethyl acetate to provide 2,3-dihydro-9-methoxy[1]benzothieno[2,3-f]-1,4-thiazepin-5(4H)-one in 74% yield, mp 209°-209.5° C.

Provenance & Evidence