Efavirenz (sustiva), a benzoxazinone derivative, is presently in clinical use for the treatment of AIDS. Recently, various benzoxazinones have been synthesised and evaluated with a view to achieving antiviral agents of choice. 1., 2. and 3. Most of the methods available for the construction of the benzoxazinone nucleus often suffer from one or more drawbacks such as the long reaction time required to obtain a good yield of the desired product or the use of expensive and ...