GlyNH2.HCl (2.65 g, 0.024 mol) is dispersed in DMF and to this is added Et3N (3.35 ml, 0.024 mol) and HOBT (3.7 g, 0.024 mol). 9.0 g (0.024 mol) of BOC-D-Lys(Z) in a large volume of DMF is added and the GlyNH2 goes into solution. The total volume of DMF is 400 ml. The reaction is stirred overnight and then filtered. The solvent is evaporated off and the residue dissolved in CH2Cl2. This is washed with citric acid solution, Na2CO3 solution and then NaCl solution, and dried with MgSO4. The mixture is filtered, the filtrate evaporated down and the residue is taken up in ethyl acetate and cooled. The solid is filtered and washed with pet ether. More solid is obtained from the filtrate. Both crops are combined and triturated with ether. 7.5 g of a tan, solid is obtained in a 71% yield:
