CAS 83-07-8 appears in our catalog under these names: Metamizole EP Impurity B (Ampyrone), 4-Aminophenazone, >95% (HPLC), 4-Amino-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one (Ampyrone), 4-Aminoantipyrine, Ampyrone/ 98.57% (existing batch purity). Offered by: Chemat Brand, TRC, Mikromol, Dr. Ehrenstorfer, TargetMol. Available pack sizes: on request, 1g, 50g, 5g, 25mg, 100mg, 10mg, 10g.