2921.43.90 - Other

This category, HTS 2921.43.90, encompasses aromatic monoamines that are derivatives of toluidines, and their respective salts, which do not fall under the specific exclusions or definitions of preceding subheadings. It serves as a residual classification for toluidine derivatives and their salts that are not explicitly listed elsewhere within the toluidine family. The classification hinges on the chemical structure, specifically the presence of a toluidine moiety combined with other functional groups or structural modifications not covered by more specific provisions.

This subheading is distinguished from its sibling, 2921.43.40.00, which specifically designates products that meet the criteria outlined in additional U.S. note 3 to Section VI. Therefore, HTS 2921.43.90 is applicable to toluidine derivatives and their salts that *do not* qualify for the specific exclusion or definition provided by that additional U.S. note. The classification relies on a careful examination of chemical composition and the absence of specific criteria met by other subheadings.

Within this category, further subdivisions exist to provide more granular classification for specific toluidine derivatives. HTS 2921.43.90.20 covers 2-Chloro-p-toluidine-5-sulfonic acid (CAS No. 88-51-7), while HTS 2921.43.90.40 pertains to p-Toluidine-m-sulfonic acid (CAS No. 88-44-8). The residual category, HTS 2921.43.90.90, is for all other aromatic monoamines derived from toluidines, and their salts, not otherwise specified. These subcategories allow for precise classification based on the exact chemical structure and any accompanying functional groups or substitution patterns.