Dimethylformamide → (+/-)-3-Butylthio-4-(3-pyrrolidinyloxy)-1,2,5-thiadiazole

Participants

Reaction Conditions

Reaction Steps

A suspension of NaH (0.22 g, 0.009 mol) in THF (30 mL) was treated with (±)-1-t-butylcarbamoyl-3-hydroxpyrrolidine (1.73 g, 0.0092 mol), and the reaction heated to reflux for 35 min. After cooling to 10° C., 3-chloro-4-ethylsulfonyl-1,2,5-thiadiazole (1.96 g, 0.0092 mol) in THF (5 mL) was added, cooling was removed, and the reaction heated to 35° C. for 16 h. The reaction was diluted with H2O, ether added, and the ether extract separated. The ether extract was washed with H2O, dried, and the solvent evaporated to give a tan liquid, (3.05 g). A DMF (42 mL) solution of the liquid was treated with freshly ground flaked Na2S-9H2O (3.3 g, 0.0138 mol). After 1 h, 1-iodobutane (3.42 g, 0.0186 mol) was added, and the reaction stirred at 40° C. for 16 h. The solvent was evaporated, the residue diluted with cold water, and the mixture extracted with ether. The ether was dried, the solvent evaporated, the residue dissolved in ether, and the solution treated with a stream of dry HCl for 5 min. After 66 h, the reaction was treated with ice-water and the organic solvent evaporated. The aqueous solution was extracted with ether, made basic, and extracted with ether. The ether extracts were dried and the solvent evaporated to give a tan liquid that was purified by radial chromatography (5% EtOH-0.5% NH4OH-CHCl3). The HCl salt (0.67 g) crystallized from EtOAc, m.p. 99-100.5° C. (Compound 53).

Provenance & Evidence