Potassium Carbonate → (7R,8R,9R)-10-Acetyl-7,8-dihydroxy-2,3-dimethyl-9-phenyl-7,8,9,10-tetrahydroimidazo[1,2-h]-[1,7]naphthyridine

Participants

Reaction Steps

160 g of (7R,8R,9R)-10-acetyl-7-hydroxy-2,3-dimethyl-9-phenyl-8-pivaloyloxy-7,8,9,10-tetrahydroimidazo[1,2-h][1,7]naphthyridine are dissolved in 0.7 l of methanol with stirring and treated with 40 g of potassium carbonate. After approximately 10 min, the product begins to precipitate from the reaction mixture. After stirring for 1 h at room temperature, it is added to a solution of 200 g of ammonium chloride in 1.8 l of ice water. It is stirred for a further 1 h at ice-bath temperature, then the precipitated solid is filtered off with suction and washed with a little methanol (80 ml). After drying at 50° C. in a vacuum drying oven, 92.0 g (73%) of the title compound are isolated as a colorless solid of m.p. 260-261° C., which is used in the next stage without further purification. Alternatively, the tile compound can also be prepared according to examples 5 and 6.

Provenance & Evidence