Sodium Hydroxide → HCID 178463032, compound

Participants

Reaction Steps

57 g. of sodium salt of 1-ethyl-6-hydroxy-1H-pyrazolo[3,4-b]pyrazine-5-carboxylic acid ethyl ester hydrate (2:1), prepared according to Example 1b, and 400 ml. of aqueous sodium hydroxide are heated to 60° with stirring for 16 hours. Then the solution is filtered and the filtrate is acidified with concentrated hydrochloric acid. The precipitated 1-ethyl-6-hydroxy-1H-pyrazolo[3,4-b]pyrazine-5-carboxylic acid is filtered off, washed with water and dried at 70°, yield 31.4 g. (71%). A sample recrystallized from acetonitrile melts at 194°-195°.

Provenance & Evidence