HCID 178486889, compound → HCID 178488820, compound

Participants

Reaction Steps

A mixture of 4,9-dihydro-5-methoxy-9-oxo-pyrazolo[5,1-b]quinazoline-2-carboxylic acid (6.6 g; 0.025 mole) and phosphorous oxychloride (100 ml) is stirred at room temperature overnight. The solid is filtered off, washed with ether, dried and treated with cold (0° C.) ammonium hydroxide solution (58%; 50 ml). After standing overnight at room temperature the product is filtered off, dried and used in the next step without further purification. Yield 5.06 g; mp 265°-270° C. By the same procedure, starting with the corresponding 6,7-dimethoxy compound, the product obtained is 4,9-dihydro-6,7-dimethoxy-9-oxo-pyrazolo[5,1-b]quinazoline-2-carboxamide.

Provenance & Evidence