SYNTHESIS OF NOVEL FLUORINATED DERIVATIVES OF 1,3-DIMETHYLBARBITURIC ACID

Synthetic utility of the novel difluoro ketene aminal 1 was extended t o the preparation of a number of potentially biologically-interesting difluoro barbituric acid derivatives via initial hetero-Diels-Alder re actions of 1 with p-substituted-5-benzylidene-1,3-dimethylbarbituric a cids 3. These cycloadducts 4 upon hydrolysis, provided the formal Mich ael addition product amides 5 which were readily converted to the resp ective carboxylic acids 6. The acids were dehydratively cyclized to fo rm novel bicyclic lactones 8. (C) 1998 Elsevier Science Ltd. All right s reserved.