Triphenylphosphine → 5-{4-[2(R)-t-butoxycarbonylaminopropoxy]benzyl}-3-triphenylmethylthiazolidine-2,4-dione

Participants

Reaction Steps

13.2 g of diethyl azodicarboxylate were added dropwise to a solution of 20.7 g of triphenylphosphine in 300 ml of benzene and the mixture was stirred at room temperature for 30 minutes. At the end of this time, 35.0 g of 5-(4-hydroxybenzyl)-3-triphenylmethylthiazolidine-2,4-dione [prepared as described in step (d) above] were added to the mixture, and the resulting mixture was stirred at room temperature for 1 hour. 13.2 g of (R)-2-t-butoxycarbonylamino-1-propanol were added to the mixture, which was then allowed to stand overnight. At the end of this time, 40.9 g of triphenylphosphine, 23.68 ml of diethyl azodicarboxylate and 33 g of (R)-2-t-butoxycarbonylamino-1-propanol were added to the reaction mixture, in that order, in 3 or 4 separate portions, and the mixture was then stirred for 2 days. After this time, the benzene solvent was removed from the reaction mixture by distillation under reduced pressure, and the residue was purified by column chromatography through silica gel, using a 1: 3 by volume mixture of ethyl acetate and hexane as the eluent, to give 30 g of the title compound as crystals, melting at 153°-157° C.

Provenance & Evidence