2933.53.00.00 - Allobarbital (INN), amobarbital (INN), barbital (INN), butalbital (INN), butobarbital, cyclobarbital (INN), methylphenobarbital (INN), pentobarbital (INN), phenobarbital (INN), secbutabarbital (INN), secobarbital (INN) and vinylbital (INN); salts thereof

This HTS category, 2933.53.00.00, specifically enumerates and classifies a distinct group of barbiturate derivatives. These compounds are primarily characterized by their inclusion of a pyrimidine ring and their medicinal or sedative properties, often employed as hypnotics or central nervous system depressants. The listed INN (International Nonproprietary Names) – such as Allobarbital, Amobarbital, Barbital, Phenobarbital, and Secobarbital – are the key identifiers for items falling under this heading. This includes the pure substances and any of their corresponding salts.

It is crucial to distinguish this category from its siblings. Unlike 2933.52, which covers malonylurea (barbituric acid) itself and its salts, or 2933.54.00.00, which encompasses other derivatives of malonylurea, 2933.53.00.00 is reserved for the specific, named barbiturate compounds. Furthermore, it differs from 2933.55.00.00, which is dedicated to a different set of heterocyclic compounds like loprazolam and methaqualone, also containing a pyrimidine ring but with distinct chemical structures and pharmacological profiles.

As a leaf node, 2933.53.00.00 does not have further subdivisions. Therefore, classification within this heading relies directly on the presence of the named barbiturate compounds or their salts. Customs professionals should verify the identity of the substance against the INN list provided in the description to ensure accurate classification. The context established by its parent, "Compounds containing a pyrimidine ring (whether or not hydrogenated) or piperazine ring in the structure," confirms that the defining feature is the pyrimidine ring system, with the specific barbiturate function being the critical determinant for this particular sub-heading.