Michael addition of ethyl acetoacetate to α-β unsaturated ketones of 3-arylsydnones:: Synthesis and antimicrobial activity of 3-(4-cinnamoyl), 4-(6′-carbethoxy-5′-aryl-cyclohex-2′-en-1′-one-3′-yl) and 4-(1′,2′,4′,5′-tetrahydro-4′-aryl-indazolin-3′-one-6′-yl)-arylsydnones

3-Aryl-4-[6'-carbethoxy-5'-aryl-cyclohex-2'-en-1'-one-3'-yl] sydnones IIIa-p were obtained from the a-p unsaturated ketones of 3'-arylsydnones IIa-p by Michael addition of ethyl acetoacetate, followed by internal Claisen condensation. Reaction of IIIa-p with hydrazine hydrate afforded the corresponding tetrahydroindazolin-3-one derivatives IVa-p.