ABSTRACT
A novel and efficient method for the synthesis of 6-substituted-7,7a-dihydro-1,7a-dimethyl-7-imino-2-phenyl-1H-pyrazolo[4,3-b]pyridin-3(2H)-ones via the reaction of 4-amino-2,3-dimethyl-1-phenylpyrazolin-5-one with ketene dithioacetals and ethoxy-methylenemalononitrile or ethyl ethoxymethylene-cyanoacetate followed by intramolecular cyclization of the products has been investigated.