condensation of substituted 1-oxo-2-formyl-3-dimethylamino-1h-naphtho [ 2,1-b ] pyrans with hydrazine or monosubstituted hydrazines led to the formation of 11-oxo-8h,11h-naphtho [ 1',2':5,6 ] pyrano [ 2,3-c ] pyrazole derivatives through the intermediate hydrazones and subsequent cyclization .
C0020233
hydrazines
C0020235
hydrazones