A. Korenova et al., SYNTHESIS OF -3-HYDROXY-2-(PYRROL-1-YLMETHYL)-1H-ISOINDOL-1-ONE - AN INTERMEDIATE FOR THE SYNTHESIS OF TETRACYCLIC SYSTEMS, Journal of heterocyclic chemistry, 35(1), 1998, pp. 9-12
N-Chloromethylphthalimide 1 and the potassium salt of pyrrole gave N-(
pyrrol-1-ylmethyl)phthalimide 2. Reduction of 2 led to the hydroxyisoi
ndolone 3. This hydroxylactam cyclized under acidic conditions to lead
to a pyrroloimidazoloisoindolone 4 via an acyliminium ion. Transforma
tion of 3 with acetic acid derivatives provided 5, 7 and 9 which gave
by intramolecular cyclization, tetracyclic compounds 6, 10 and 11.