Triphenylphosphine → tert-Butyl 3-[(4-{[(5-chloro-2-thienyl)carbonyl]amino}-1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)methyl]benzylcarbamate

Participants

Reaction Steps

2.41 ml (15.4 mmol) of diethyl azodicarboxylate (DEAD) are added dropwise to a mixture, cooled with water, of 3.37 g (11 mmol) of 5-chloro-N-(1,3-dioxo-2,3-dihydro-1H-isoindol-4-yl)-2-thiophenecarboxamide, 3.26 g (13.8 mmol) of tert-butyl 3-(hydroxymethyl)benzylcarbamate and 4.04 g (15.4 mmol) of triphenylphosphine in 60 ml of absolute THF. The reaction mixture is stirred vigorously at room temperature for 90 min and then concentrated to a volume of about 30 ml. 300 ml of ether are added to the solid and the mixture is filtered. Another crystallization of the mother liquor yields a second batch. The product is dried under high vacuum. Alternatively, the product can be purified by column chromatography on silica gel (dichloromethane/methanol mixture or cyclohexane/ethyl acetate mixture). Yield: 4.79 g (82.8% of theory);

Provenance & Evidence