Solid-phase synthesis of 1,4-benzodiazepine-2,5-diones. Library preparation and demonstration of synthesis generality

A general and expedient method has been developed for the solid-phase synthesis of 1,4-benzodiazepine-2,5-diones 1 from three commercially available components; anthranilic acids, alpha-amino esters, and alkylating agents. Reaction conditions have been developed to prepare either racemic compounds for lead identification efforts or optically pure compounds for lead optimization efforts. The incorporation of diverse functionality into the benzodiazepine products has also been demonstrated. On the basis of the scope and generality of the synthesis sequence, a library of 1,4-benzodiazepine-2,5-diones has been prepared from 11 alkylating agents, 12 anthranilic acids, and 19 alpha-amino esters (nine sets of enantiomeric pairs and glycine methyl ester hydrochloride). The library was prepared in a spatially separate format using a microtiter-based apparatus that is inexpensive and straightforward to construct from ordinary items found in an organic or bioorganic laboratory. The high quality of the 1,4-benzodiazepine-2,5-dione library has been demonstrated by evaluating representative compounds by HPLC analysis and H-1 NMR.