L Alanyl-D-isoglutamine benzyl ester

Fig. 3. Synthesis of r-butyloxycarbonyl-L-alanyl-D-isoglutamine benzyl ester (43)...

After debenzylidenation of benzyl-4,6-0-benzylidene-N-acetyl-mura-myl-L-alanyl-D-isoglutamine benzyl ester in the usual manner by 60% acetic acid at 100°, the ensuing 4,6-diol derivative can be acylated spe-... 

Activated ester coupling methods have also been used. The 1-suc-cinimidyl ester of l-a-0-benzyl-4,6-0-benzylidene-N-acetyl-muramide, prepared using N,N- -dicyclohexylcarbodiimide, was allowed to react with the dipeptide derivative (33). The 5-norbomene-2,3-dicarboxyimidyl ester of 4,6-O-anisylidene-N-acetyl-muramide can be readily coupled with the triethyl-ammoniinn salt of L-alanyl-D-isoglutamine (55). 

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