2933.19.18.00 - 2-Chloro-5-sulfophenylmethylpyrazolone; 2,5-Dichloro-4-(3-methyl-5-oxo-2- pyrazolin-1-yl) benzenesulfonic acid; Phenyl carbethoxypyrazolone;m-Sulfaminopyrazolone (m-Sulfamido- phenyl methyl pyrazolone); and 1-(p-Sulfophenyl)-3-methyl pyrazolone

This HTS category encompasses a specific group of pyrazolone derivatives that are aromatic or modified aromatic in nature. These compounds are characterized by the presence of a pyrazole ring fused within or attached to an aromatic structure, and are further distinguished by the functional groups and substituents present. The listed examples, including various chlorinated and sulfonated phenylmethylpyrazolones and phenyl carbethoxypyrazolone, highlight the chemical complexity and specific applications of the substances classified here.

This classification is distinct from its siblings primarily through the precise chemical structures and substituents of the compounds it covers. For instance, sibling categories like 2933.19.04.00 and 2933.19.08.00 include different arrays of aminopyrazoles, tolyl pyrazolones, and other substituted pyrazolone sulfonic acids, each with unique chemical configurations. Similarly, 2933.19.15.00 covers a specific quaternary pyrazolium salt. This node, therefore, acts as a residual category for aromatic or modified aromatic pyrazolone compounds not specifically enumerated in other more narrowly defined subheadings.

As this node represents a leaf node within the HTS structure, it does not have further subcategories. Classification under 2933.19.18.00 relies on the precise chemical identity and description of the imported goods matching one of the listed compounds or falling under the general "other" provision for similar aromatic or modified aromatic pyrazolone derivatives not otherwise specified. This ensures that a wide range of complex organic chemical intermediates and products based on the pyrazolone structure are appropriately accounted for within the tariff system.