N-Boc thiourea → Tert-butyl 4-(methylthio)thiazol-2-ylcarbamate

Participants

Reaction Steps

N-tert-butoxycarbonylthiourea (503, 0.841 g, 4.77 mmol, prepared according to Schiavi, B.; Ahond, A.; Poupat, C.; Potier, P. Synth. Commun. 2002, 32, 1671) was suspended in ethanol (7.0 mL) and cooled in an ice bath. A solution of S-methyl bromoethanethioate (1.371 g, 5.0582 mmol, prepared according to Praveen Rao, P. N.; Amini, M.; Li, H.; Habeeb, A. G.; Knaus, E. E. J. Med. Chem. 2003, 46, 4872-82) in ethanol (7.0 mL) was added dropwise over 3 minutes. The suspension turned homogeneous at the end of the addition, the bath was removed, and the reaction was stirred at room temperature. The solvent was removed, and the crude material was partitioned between dichloromethane and water. The organics were washed with water and brine. The combined aqueous layers were back-extracted with dichloromethane, and the combined organics were dried with anhydrous MgSO4, filtered, and concentrated in vacuo to an orange glass (stench). The crude material was adsorbed onto ca. 5 g silica gel with ethyl acetate, and flushed through a plug of silica gel with hexanes (discarded) followed by 9:1 hexanes:ethyl acetate. The eluent was evaporated in vacuo to yield 504 (589 mg, 50%) as a colorless solid.

Provenance & Evidence