1 GCK Phosphoric acid 9-(2-guanidinoethoxy-3-(2-deoxy-beta-D-erythropentofuranosyl))-3h-pyrimido-[5,4-B][1,4]-benzooxazin-2-one]-5'-ester 1.000 2 YCO 3-(2-deoxy-5-O-phosphono-beta-D-erythro-pentofuranosyl)-1h-pyrimido[5,4-B][1,4]benzoxazin-2(3h)-one 0.794 3 TC1 3-(5-phospho-2-deoxy-beta-D-ribofuranosyl)-2-oxo-1,3-diaza-phenothiazine 0.743