Dicyclohexylcarbodiimide → l-tryptophyl-D-alanine

Participants

Reaction Steps

Nα -Benzyloxycarbonyl-L-glutaminyl-L-prolyl-Nim -benzyl-L-histidyl-Nim -benzyl-L-histidyl-O-benzyl-L-tyrosyl-O-benzyl-L-seryl=l-tryptophyl-D-alanine resin is prepared by the General Procedure, given below, by successive coupling of 30 g. (0.0198 mol) of Nα -t-butoxycarbonyl-D-alanine resin with 1.) 9.1 g (0.03 mol) of Nα -t-butoxycarbonyl-L-tryptophan and 6.8 g. (0.03 mol) of dicyclohexylcarbodiimide, 2.) 9.0 g. (0.03 mol) of Nα -t-butoxycarbonyl-O-benzyl-L-serine and 6.8 g. (0.033 mol) of dicyclohexylcarbodiimide, 3.) 11.1 g. (0.03 mol) of Nα -t-butoxycarbonyl-O-benzyl-L-tyrosine and 6.8 g. (0.033 mol) of dicyclohexylcarbodiimide, 4.) 10.5 g. (0.03 mol) of Nα -t-butoxycarbonyl-Nim -benzyl-L-histidine and 6.8 g. (0.033 mol) of dicyclohexylcarbodiimide, 5.) 10.5 g. (0.03 mol) of Nα -t-butoxycarbonyl-Nim -benzyl-L-histidine and 6.8 g. (0.033 mol) of dicyclohexylcarbodiimide, 6.) using 2/3 of the resin obtained in Step 5 with 4.4 g. (0.02 mol) of Nα -t-butoxycarbonyl-L-proline and 4.6 g. (0.022 mol) of dicyclohexylcarbodiimide and 7.) using 1/2 of the resin obtained in Step 6 with 8 g. (0.02 mol) of Nα -benzyloxycarbonyl-L-glutamine p-nitrophenyl ester in dimethylformamide solution and the excess removed by drainage.

Provenance & Evidence