The conversion of 3-phenylphthalic anhydride into cyclopent[a]indene (
benzopentalene) by flash vacuum pyrolysis (FVP) is not unique; eightee
n biphenyl-based anhydrides, allyl esters and bis-allyl esters can for
m benzopentalene. Similarly, triphenylene derivatives with 1,2-, 1,3-,
1,4- and 2,3- anhydride or bis-allyl ester functions form cyclopent[h
,i]acephenanthrylene on FVP.