HCID 178513504, compound → HCID 178513502, compound

Participants

Reaction Steps

A mixture of 4,9-dihydro-9-oxo-pyrazolo[5,1-b]-quinazoline-2-carboxylic acid (5 g; 0.022 mole), thionyl chloride (250 ml) and four drops of pyridine is stirred at room temperature for 24 hrs. The reaction mixture is evaporated to dryness under reduced pressure in a water bath at 30°-40° C. The residue is treated with cold (0° C.) concentrated ammonium hydroxide solution (200 ml) and allowed to come to room temperature. The product is filtered off, washed with ether and used in the next step without further purification. Yield 3.2 g; mp 315°-325° C. An analytical sample, recrystallized from dimethylformamide, melts at 335°-340° C. By the same procedure, starting with the corresponding 7-fluoro compound, the product obtained is 4,9-dihydro-7-fluoro-9-oxo-pyrazolo[5,1-b]quinazoline-2-carboxamide.

Provenance & Evidence