Synthesis of new PCDA-carbohydrate derivatives

The synthesis of new 10,12-pentacosadynoic acid (PCDA), which is a tagging carbohydrates with PCDA dye was examined. The β-D-glucose penta-acetate was transformed into corresponding β-azide. β-D-glucose pentaacetate azide was reduced with p-toluenesulfonic acid to get carbohydrate p-TSA ammonium salt in good yield. The crude 10,12-pentacosadynoyl chloride which was in turn prepared from the PCDA and oxalyl chloride was react with p-TSA ammonium salt to get the glucose acetate derivative with PCDA tail. The glucose acetate derivative has undergone deprotection reaction with methanol and sodium methoxide to get the carbohydrate-PCDA amide 5 with 55% yield. The galactose-PCDA amide was synthesized by the deprotection of galactose pentaacetate-PCDA amide with 45% yield.