Esterification Chapter catalysis

The 1,3 dipole diazomethane is a mild reagent to furnish methyl esters (see Chapter 13), but it has some disadvantages, too it is volatile, toxic and furthermore explosive. For this reason it has to be prepared by reaction of KOH with 7V-methyl-7V-nitroso-/ ara-toluenesulfon-amide (carcinogenic ) or in situ.11 Another simple method to protect the COOH functionality of the neuraminic acid is the esterification with methanol as solvent and reactand under H+ catalysis e. g. ion exchanger. 

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