0.2 g gitoxin was dissolved in 15 ml of dimethylformamide and mixed with 2
ml of acetanhydride, 3 ml formic acid (98%) and 2 ml triethylamine or
pyridine. The reaction mixture stood for 60 min. at room temperature, then it
was diluted with water, a precipitated product was filtered off. A filtrate was
shook with chloroform 2 times. Chloroform was distilled to dryness and the
residue was added to the precipitate. 16-Formylgitoxin was isolated by
fraction crystallization. MP: 250°-253°C, yield about 50%.
