Tetrahydrofuran → HCID 53714300, compound

Participants

Reaction Conditions

Reaction Steps

To a solution of N-[[1-[4-(methylsulfonyl)butyl]cyclopentyl]carbonyl]-4-nitro-L-phenylalanine methyl ester (33 mmol, 15 g) in toluene (100 mL, stored over 4 Å molecular sieves) and freshly distilled THF (50 mL) was added Lawesson's reagent (33 mmol, 13.35 g, 1.0 equiv.) at room temperature. The solution was heated to 60-65° C. and was stirred for 48 h at which time TLC analysis of the mixture indicated the absence of starting material. The reaction mixture was cooled to room temperature and was poured into saturated sodium bicarbonate solution (200 mL) and extracted with ethyl acetate (3×150 mL). An oil formed in the aqueous layer, which was separated, diluted with water and extracted with ethyl acetate (2×50 mL). The combined ethyl acetate extracts were washed with saturated sodium bicarbonate solution (200 mL), with brine (300 mL), dried (MgSO4), filtered and the solution was concentrated in vacuo. The residual light brown syrup was purified by silica gel column chromatography (hexane:ethyl acetate, 1:1) to obtain 6.87 g (44%) of N-[[1-[4-(methylsulfonyl)butyl]cyclopentyl]thioxo-methyl]-4-nitro-L-phenylalanine methyl ester as a fluffy yellow solid. HRMS: Obs. mass, 493.1438. Calcd. mass, 493.1443 (M+Na).

Provenance & Evidence