4.06 g of 2-[N-(Boc)amino]-3-(4-cyanophenyl)propionic acid are mixed with 1.15 ml of pyrrolidine and 7.5 g of BOP in 20 ml of DMF; the mixture is left stirring for 2 hours at RT while maintaining at pH=7 by addition of Et3N. After evaporating to dryness, the residue is chromatographed on silica, eluting with a chloroform/methanol mixture (9/0.5; v/v). After evaporating off the solvents, the solid obtained is treated with 20 ml of TFA in 20 ml of DCM for 30 minutes at RT. The solvents are evaporated off and the residue is taken up in ether and then dried in order to obtain 3.95 g of the expected product.
