On the reaction behavior of beta-oxo carbonic acid derivatives of the anthracene series in pyrazole synthesis

beta-Oxo-1 and 9-anthracenepropionate (6 and 7) reacts with DMF-acetate to enaminones 10 and 11. The reaction of 2-(dimethylamino)methylen-substituted beta-oxo-1-anthracenepropionate (10) with hydrazines yields 5-(1-anthracen yl)-pyrazol-4-carboxylates (13). In contrast, the cyclocondensation of 3-(9 -anthracenyl)-2-(dimethylamino)meth (11) with hydrazine hydrochlorides give s 4-(9-anthracenoyl)-5-hydroxy-pyrazoles (14). This is caused by the steric al hindrance of the carbonyl group of the anthracene derivatives in positio n 9; thus, the cyclocondensation proceeds via reaction of the ester group o f the enaminone 11.