Osmania University, India
Several heteroannelated quinazolinone derivatives, isolated from natural sources or prepared by synthetic designs, are known to interact with DNA/DNA enzymes. Examples include the alkaloids such as vasicinone (1), isolated from Adhatoda vasica (Acanthaceace), and luotonin-A (2), isolated from Peganum nigellastum (zygophyllaceace). These molecules with an indolizino[1,2-b]quinazolinone scaffold are DNA interacting with specific cytotoxicity on the human prostrate carcinoma PC3 cell line. Their synthetic analogues batracyclin (3) and tyrosine-kinase inhibitor PD153035 (4) are anti- cancer drugs. We aimed at the synthesis of planar quinazolinones as DNA intercalating agents like the natural product luotonin A, synthesis of a novel pentacyclic quinazolinone derivative – pentaphenedione was carried out starting from 2-aminobenzhydroxamic acid. This was achieved in three steps starting from preparation of 3,3'-dihydroxy-2,2'-bisquinazolin-4,4'-dione from 2-aminobenzhydroxamic acid followed by its conversion to 3,3’-diamino-2,2’-bisquinazolin-4,4’-dione which on oxidative cyclisation gave 5a,6,7,7a,13,14- hexaaza-pentaphene-5,8-dione.