Influence of pH on the acylation of l-hydroxyproline with palmitoyl chloride in an aqueous acetone medium

Acylation reactions under schotten-bauman condition depend largely on the ph of the reaction medium. when the ph of the reaction medium was 9.0-10.0,the acylation of 0.1 mol of hydroxyproline with 2.5 mol of palmitoyl chloride in an aqueous acetone medium gave o-palmitoyl hydroxyproline and palmitic acid. in another reaction at a ph of 10.5-13.0,a small portion of the formed o-palmitoyl hydroxyproline was converted into n,o-di-palmitoyl hydroxyproline which is only between the range of 4.79% to 10.78%. however,at more higher ph values,the n-acylation reaction competed with hydrolysis of the formed o-palmitoyl hydroxyproline to regenerate palmitic acid and l-hydroxyproline which resulted in the reduction of percentage of n,o-di-palmitoyl hydroxyproline of 9.00%.