Synthesis of new 1,2‐dihydrophthalazines

New 6‐chloro‐ and 6,7‐dichloro‐4‐(4‐aminophenyl)‐2‐(N‐alkylcarbamoyl)‐1,2‐dihydrophthalazines ( 12,18 ) were synthesized starting from 6‐chloro‐ and 6,7‐dichloro‐4‐(4‐nitrophenyl)phthalazine ( 8 ). Routes to 1‐unsubstituted ( 12 ) and 1‐methyl ( 18 ) derivatives are different. Key intermediates 8 were prepared from 4‐chloro‐ and 3,4‐dichlorotoluene via ortho‐formylbenzophenone derivatives 7 .