Phthalazine誘導体に関する研究(第8報)1-PhthalazinecarbonitrileとCarbanionとの反応について

抄録

Reaction with 1-phthalazinecarboniteile (I) was attempted with active methy1ene compounds and ketones as the compounds forming a carbanion, in benzene, in the presence of sodium amide. Active methylene compounds used were pheny1acetonitri1e (IIa), ethyl cyanoacetate (IIb), ethyl malonate (IIc), and ethyl acetoacetate (IId), and ketones used were diethyl ketone (IIIa), acetophenone (IIIb), and cyclopentanone (IIIc). From the types of reaction products formed, two types of the reaction was assumed ; one (A-type reaction) in which the carbanion attacks the ring-carbon at 1-position in I to form 1-substituted phthalazine and the other (B-type reaction) in which the carbanion attacks the ring-carbon at 4-position to form 3, 4-dihydro-1-phthalazinecarbonitrile derivatives (Chart 1). In addition, products correspondnig to secondary reactions (B₁, B₂, and B₃ types) were obtained indicating that the reaction progressed after attack of the ring-carbon at 4-position. Product from A-type reaction was a-phenyl-1-phthalazineacetonitrile (IV) from IIa and that from B-type reaction was 3, 4-dihydro-4-(1-methyl-2-oxobutyl)-1-1-phthalazinecarbonitrile (V) from IIIa. In the case of B₁-type reaction, ethyl α, 4-dicyano-1-phthalazineacetate (VI) was obtained from IIb and 4-phenacyl-1-phthalazinecarbonitrile (VII) from IIIb (Chart 3). In the case of B₂-type reaction, 4, 4'-methylene-bis-(1-phthalazinecarbonitrile) (VIII) was obtained from both IIc and IId (Chart 4), and as B₃-type reaction product, 2, 3-dihydro-1H-benz[f]indene-4-carbonitrile (IX) was obtained from IIIc (Chart 5).