HCID 178488820, compound → HCID 178488819, compound

Participants

Reaction Steps

A suspension of 4,9-dihydro-5-methoxy-9-oxo-pyrazolo[5,1-b]quinazoline-2-carboxamide (5.05 g; 0.0195 mole) in phosphorous oxychloride (100 ml) is heated under reflux for 2 hrs. After standing two days at room temperature, excess phosphorous oxychloride is removed under reduced pressure and the residue suspended in saturated sodium bicarbonate solution (100 ml). The solid is filtered off, washed with water and dried. Yield 3.0 g; mp 292°-297° C. (d). Starting with the corresponding 7-fluoro, 8-trifluoromethyl and 6,7-dimethoxy compounds, the products obtained are, respectively, the 7-fluoro, 8-trifluoromethyl and 6,7-dimethoxy-4,9-dihydro-9-oxo-pyrazolo[5,1-b]quinazoline-2-carbonitriles

Provenance & Evidence