Dimethylformamide → BOC-Lys(CBZ)-Gln-Nle-OMe

Participants

Reaction Steps

H-Gln-Nle-OMe.TFA salt (XII) (13 mmol) triethylamine (1.76 ml, 13 mmol), HOBT (2.16 g, 16 mmol) and BOC-Lys(CBZ)-ONP (7.6 g, 15 mmol) were dissolved in DMF (30 ml). The reaction mixture was kept basic with small amounts of triethylamine. The mixture was stirred overnight at room temperature, concentrated in vacuo and treated with unsymmetrical dimethylethylenediamine (2 equivs). After 2 hours, EtOAc was added and the product was isolated as described for compound (XI). The solid was washed with petroleum ether (bpt 40°-60° C.) and dried in vacuo over silica gel to give (XIII) (5.5 g; 65%) [αD26 =-16.49° (C=1, DMF) T.l.c. RfA3 0.8.

Provenance & Evidence