DERIVATIVES OF OXALYLDIMALONIC ACID

Starting with furanone 3 and mesoxalic acid esters, the compounds 8 as monolactones of the title compound have been synthesized. A versatile intermediate is the dioxinone 15, the masked acylketene 16. Regiosele ctive partial saponification 8a led to the diester 8e which was conver ted into the dilactone 2. The enamine 8d isomerizes by two pathways. B y alkanolate catalysis the gamma-alkylidenetetramic acid 24 was obtain ed and used to prepare the lactam-lactone 25 and the dilactam 27. Ther mal isomerization of 8d gave the cyclic tetracarbonylmethane derivativ e 19. Ring opening reactions of 19 did not furnish derivatives of the title compound but the isomeric acids 20-23. Some open-chain derivativ es of oxalylbismalonic acid (12, 26) were obtained from 8c/8d by lacto ne cleavage.