Routes to HIV-integrase inhibitors: efficient synthesis of bicyclic pyrimidones by ring expansion or amination at a benzylic position

Ring expansion of [6,6] bicyclic pyrimidones led, through an aziridinium intermediate, to potent HIV-integrase inhibitors with a [7,6] core. A more flexible and diversity-oriented synthesis of functionalized pyrimidohexahydrodiazepines was then developed; the key benzylic substituent was introduced in one pot by using sequentially DDQ and BnMeNH. Both synthetic routes are described.