Ortho Anisidine

Ortho Anisidine (2-methoxyaniline) places a methoxy group ortho to the amino group on the benzene ring, giving a reactive aromatic amine used for decades as a dye and pigment intermediate. We want to flag something precisely, because the two major classification systems covering this compound use very similar-looking labels for very different things: the EU's harmonised CLP Annex VI entry lists it as Carc. 1B (H350, presumed to have carcinogenic potential for humans, based largely on animal bladder-tumour data), while IARC separately evaluated it and placed it in Group 2B (possibly carcinogenic to humans). "1B" and "2B" are not the same scale and should never be read as if one confirms or contradicts the other at face value -- we state both, on their own terms, rather than merge them into a single simplified label.

Commercially, Ortho Anisidine is a well-documented intermediate in azo-dye and organic-pigment manufacture, including several Pigment Red and Pigment Orange grades built from its diazotised form, and it has historical use as an intermediate toward certain antioxidants and pharmaceuticals, though we focus here on its dominant, best-documented dye/pigment role.

Where it fits in the synthesis chain

We supply Ortho Anisidine itself as a dye and pigment intermediate. We do not manufacture or supply the finished dyes or pigments made from it.

Grades we supply

99%+ is the standard commercial grade.

Ortho Anisidine is made industrially by reduction of ortho-nitroanisole, itself typically made by methylation of ortho-nitrophenol or by nitration of anisole followed by isomer separation.

The nitro-to-amine reduction step uses catalytic hydrogenation or a chemical reducing agent, converting the nitro group cleanly to the amine while leaving the methoxy group and ring untouched.

The crude product is purified by distillation under reduced pressure, since it darkens readily on exposure to air and light, and is tested for purity and colour before packing under conditions that limit further oxidative discoloration.

Two classification systems, two different numbers -- kept separate on purpose

We want to state this as plainly as we can: the EU's Carc. 1B classification and IARC's Group 2B evaluation are not the same scale, and the shared digit between "1B" and "2B" is coincidental, not a sign the two systems roughly agree. EU Carc. 1B means substances presumed to have carcinogenic potential for humans, based substantially on animal evidence -- here, documented bladder tumours in rodent studies. IARC Group 2B means possibly carcinogenic to humans, a category IARC applies where evidence is limited in humans and less than sufficient in animals, or sufficient in animals but the broader picture is still judged as only "possible." These are two independent regulatory judgments on the same underlying data, not two readings of the same scale, and we report each on its own terms.