3-Oxo-2-(4-oxo-3,4-dihydro-benzo[4,5]furo[3,2-d]pyrimidin-2-ylmethyl)-butyric acid ethyl ester

2-carbethoxy-1,2-dihydrobenzofuro<3,2-d>pyrrolo<1,5-a>pyrimidine-3,5-dione

2-(2'-carboxy-2'carbethoxyethyl)-3,4-dihydro-4-oxobenzofuro<3,2-d>pyrimidine

2-(2',2'-dicarbethoxyethyl)-3,4-dihydro-4-oxobenzofuro<3,2-d>pyrimidine