preparation of nitroorotic acid via nitration of orotic acid application_number US 201313945011 A description nitroorotic acid ii is produced by nitration of orotic acid i according to reaction scheme 1 as the reagent a mixture of concentrated sulphuric acid and concentrated but not fuming nitric acid is used preferably the concentration of the sulphuric acid is 98 and the concentration of the nitric acid is 65 usually sulphuric acid and nitric acid are mixed in a molar ratio of between 1 1 and 6 1 preferably the ratio of sulfuric acid to nitric acid is about 3 1 in mole the nitration is carried out at a temperature of about 40 80 u00b0 c the preferred reaction temperature is about 40 60 u00b0 c even more preferred is a reaction temperature of about 50 60 u00b0 c nitroorotic acid obtained via nitration of orotic acid with cooling below 50 u00b0 c 420 ml 7 68 mol concentrated sulphuric acid h 2 so 4 approx 98 were added to 169 ml 2 56 mol 65 nitric acid hno 3 then 200 g orotic acid 1 28 mol purity 99 64 were added portionwise the reaction mixture was heated to 50 55 u00b0 c under stirring for 3 hours after completion of the nitration the reaction.