4-AMINO-5-BROMO-3,4-DIHYDRO-1-[(6R,7R)-TETRAHYDRO-2,7-DIHYDROXY-2-OXIDO-4H-FURO[3,2-D]-1,3,2-DIOXAPHOSPHORIN-6-YL]-2(1H)-PYRIMIDINONE AMMONIUM SALT