Synthesis of dl-4xi-(2-carboxyethyl)-cis-hexahydropyrrolo-[3,4-d]imidazol-2-one (bisnorazabiotin)

Bisnorazabiotin was synthesized in a six-step sequence from 1,5-dioxo-2-carbethoxypyrrolizidine. It is anticipated that the molecule will serve as a cofactor for biotin-requiring enzymes.