2906.13 - Sterols and inositols:

This HTS category, 2906.13, encompasses sterols and inositols, which are cyclic organic compounds derived from the broader group of cyclanic, cyclenic, or cycloterpenic alcohols and their derivatives. Sterols are a class of naturally occurring compounds with a characteristic four-ring structure, including well-known examples like cholesterol and phytosterols, often found in animal and plant tissues respectively. Inositols are a group of carbocyclic sugars, isomers of glucose, with myo-inositol being the most common naturally occurring form. These compounds are distinct from other classifications within cyclic alcohols based on their specific chemical structures and biological functions.

While sibling categories such as 2906.11.00.00 (Menthol) and 2906.12.00.00 (Cyclohexanol, methylcyclohexanols, and dimethylcyclohexanols) also fall under cyclanic alcohols, they are distinguished by their specific functional groups and common applications. Menthol is primarily known for its cooling sensation, while cyclohexanol derivatives are often used as solvents or intermediates in chemical synthesis. Category 2906.13, however, specifically isolates sterols and inositols, recognizing their unique chemical architectures and often biological roles, differentiating them from alcohols with simpler cyclic structures.

The subcategories within 2906.13 further refine the classification of these compounds. 2906.13.10.00 specifically covers inositols, providing a distinct code for these sugar-like cyclic alcohols. The residual category, 2906.13.50.00, is designated for "Other," which would include all other sterols not specifically itemized elsewhere within the tariff schedule. This hierarchical structure allows for precise identification of these specialized organic chemicals based on their specific chemical identities.