On the behavior of α‐brominated dimethyl o ‐benzenediacetate toward nitrogen nucleophiles . Part I. Reaction of dimethyl α,α'‐dibromo o ‐benzenediacetate with hydrazines

Meso‐ ( 1a ) and racemic dimethyl α,α'‐dibromo o ‐benzenediacetate ( 1b ) when condensed with hydrazine and methylhydrazine furnished respectively 1,3‐dicarbomethoxyisoindole ( 5a ) and its N ‐methyl derivative ( 5b ). Reaction of phenylhydrazine with 1a led to the N ‐phenylisoindole ( 5c ) and to the N ‐anilino isoindoline ( 6 ) as the cis isomer; conversely, 1b was transformed into a mixture of the 2‐phenyl‐1,2,3,4‐tetrahydrophthalazine ( 7 ), the trans isomer of ( 6 ), the N ‐anilinoisoindole ( 5d ) and dimethyl α‐( N '‐phenylhydrazino)‐ o ‐benzenediacetate ( 8 ). Compounds 1a and 1b were also condensed with acetylhydrazine to give a mixture of the N ‐acetylaminoisoindoline ( 12 ) and of the 2‐acetyl‐1,2,3,4‐tetrahydrophthalazine ( 13 ).