the synthesis involves 1 ) oxidation to the 21-dehydro compound with methanolic cupric acetate , 2 ) further oxidation to the acid with methylene blue in the presence of kcn at ph 6.5 , 3 ) esterification with diazomethane in the presence of methanol or ethanol , to produce the methyl ester of ta ( tame ) or ethyl ester , respectively , and 4 ) purification of the products by tlc and hplc .
C0001963
methanol
C0001962
ethanol