Liquid phase peptide syntheses of KL-4 pulmonary surfactant

Abstract

The invention realtes to improved liquid phase processes for the preparation of the 21 residue protein component, (Lys-Leu 4 ) 4 -Lys, of the pulmonary surfactant KL-4. These process are amenable to large scale synthesis and one process employs a method of saponifying an ester which reduces the inherent racemization of the α-carbon.

1 - 17 . (canceled)  
     
     
         18 . A method of deprotecting a peptide's ester protected carboxy group, having an α chiral center which consists of reacting said peptide ester with a tetraalkylammonium hydroxide and water in an inert organic solvent at a low temperature to form the deprotected peptide's carboxy group.  
     
     
         19 . The method of  claim 18  wherein, the tetraalkylammonium hydroxide is tetrabutylammonium hydroxide, the inert organic solvent is DMF or THF and the temperature is about −20 to 0 C.  
     
     
         20 - 24 . (canceled)