HS 293321 Compounds containing an unfused imidazole ring (whether or not hydrogenated) in the structure
Quick Answer: HS code 293321 covers chemical compounds characterized by an unfused imidazole ring in their molecular structure, whether or not hydrogenated. This includes various heterocyclic compounds used primarily as intermediates in pharmaceuticals, agrochemicals, and specialty chemicals. For instance, it encompasses substances like hydantoin and its derivatives. Importers and customs brokers should note the varying duty rates: the UK generally applies a 6.00% ad valorem duty. The EU TARIC system typically levies a 6.50% ad valorem duty, though some specific entries may be 0.00%. In the US, the general duty rate is 6.5% ad valorem, but significant preferential duty treatment (Free) is available under various Free Trade Agreements (e.g., A, AU, CL, KR, SG). A higher Column 2 rate of 15.4¢/kg + 63% applies to goods from non-MFN countries. Careful origin determination is crucial to leverage these preferential rates.
What Are the Import Duty Rates?
🇬🇧 United Kingdom
| Code | MFN | Preferential | Unit |
|---|---|---|---|
| 2933210045 | 6.00 % | — | — |
| 2933210055 | 6.00 % | — | — |
| 2933210080 | 6.00 % | — | — |
| 2933210000 | — | — | — |
| 2933210050 | 6.00 % | — | — |
🇪🇺 European Union (TARIC)
| Code | MFN | Preferential | Unit |
|---|---|---|---|
| 2933210000 | — | — | — |
| 2933210045 | 6.50 % | — | — |
| 2933210050 | 6.50 % | — | — |
| 2933210090 | 0.00 % | — | — |
| 2933210055 | 6.50 % | — | — |
🇺🇸 United States (HTSUS)
| Code | MFN | Preferential | Unit |
|---|---|---|---|
| 2933210000 | 6.5% | Free (18 programs) | ["kg"] |
Special rates available under trade agreements including USMCA, KORUS, GSP.
Duty rates sourced from the USITC (US International Trade Commission) Harmonized Tariff Schedule (HTS) (accessed 2/22/2026), EU TARIC – DG TAXUD (Directorate-General for Taxation and Customs Union) (accessed 2/22/2026), and UK Trade Tariff – HMRC (His Majesty's Revenue and Customs) (accessed 2/22/2026).
Data compiled and presented by HSRates.
Which Trade Agreements Reduce Duties for HS 2933.21?
Imports of Compounds containing an unfused imidazole ring (whether or not hydrogenated) in the structure may qualify for reduced or zero duty rates under free trade agreements and preferential programs. The overview below shows available preferential arrangements by jurisdiction, compiled by HSRates from official tariff and trade agreement data.
United States (HTSUS)
Free for USMCA, KORUS, GSP, and 15 other programs
European Union (TARIC)
Preferential rate data not yet available.
United Kingdom
Preferential rate data not yet available.
Preferential rates require proof of origin and may be subject to quotas or conditions. Always verify eligibility with a licensed customs broker.
Data compiled by HSRates.
Which Preferential Rates Apply to Your Origin Country?
Select an origin country to see if preferential rates apply.
Preferential rates based on available trade agreements. Actual rates may vary.
How to Classify This HS Code?
What products does HS 293321 cover?
This subheading covers compounds containing an unfused imidazole ring, whether or not hydrogenated, within their chemical structure. The imidazole ring is a five-membered heterocyclic aromatic ring containing two nitrogen atoms at non-adjacent positions. This classification is specifically for compounds where the imidazole ring is not fused to another ring system, meaning it exists as a distinct, separate ring. Examples include imidazole itself, 2-methylimidazole, and other derivatives where the imidazole core remains unfused, as defined by the World Customs Organization's Harmonized System Nomenclature and reflected in the USITC Harmonized Tariff Schedule of the United States (HTSUS) and the EU TARIC system.
What falls outside HS 293321?
The following products are excluded from HS 293321: compounds where the imidazole ring is fused to another ring system, such as benzimidazole derivatives (e.g., omeprazole, which would typically fall under 2933.99). Additionally, heterocyclic compounds containing only one hetero-atom, or those containing other types of hetero-atoms (e.g., thiazoles, oxazoles), are excluded and classified under their respective specific subheadings within Chapter 29. Polymers, even if derived from imidazole monomers, are also excluded from Chapter 29 and are classified in Chapter 39. Medicaments containing imidazole derivatives as active pharmaceutical ingredients are classified in Chapter 30.
What are common classification mistakes for HS 293321?
A common error is misclassifying compounds with a fused imidazole ring system within this subheading, rather than under the more general residual subheading 2933.99 for other heterocyclic compounds with nitrogen hetero-atoms. Another frequent mistake involves overlooking the "unfused" criterion, leading to incorrect classification of complex molecules like certain pharmaceuticals where an imidazole moiety is part of a larger, fused polycyclic system. Importers sometimes also confuse simple imidazole derivatives with preparations or mixtures containing them, which, if formulated for specific uses (e.g., as pesticides or medicaments), would fall into Chapters 30, 38, or other relevant chapters, guided by General Interpretative Rule 3(b).
How should importers classify products under HS 293321?
The correct procedure for classifying products under HS 293321 involves a thorough chemical analysis to confirm the presence of an unfused imidazole ring in the compound's structure. Importers and customs brokers should obtain the Chemical Abstracts Service (CAS) number and the full chemical name, along with the structural formula, from the manufacturer. This information is crucial for verifying that the imidazole ring is indeed unfused and not part of a larger, fused ring system. Consultation of the WCO Explanatory Notes for Heading 2933 is highly recommended. If uncertainty persists, a binding tariff information (BTI) ruling from the relevant customs authority (e.g., CBP in the US, national customs authorities in the EU) should be sought to ensure compliance and avoid potential penalties.
Which HS Codes Are Related?
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FAQ
What are the typical Most Favored Nation (MFN) import duty rates for products classified under HS 2933.21?
For products classified under Harmonized System (HS) subheading 2933.21, which covers 'Compounds containing an unfused imidazole ring (whether or not hydrogenated) in the structure,' the typical MFN (Most Favored Nation) import duty rates can vary by importing country. Based on common tariff schedules, these rates frequently fall within the range of 6.00% to 6.50% ad valorem. For instance, the Harmonized Tariff Schedule of the United States (HTSUS) may list a rate of 6.5% ad valorem for general category imports. Importers should always consult the specific tariff schedule of the destination country (e.g., USITC HTSUS, EU TARIC, UK Trade Tariff) for the precise and current MFN duty rate applicable at the time of importation.
What are the key classification criteria for determining if a chemical compound falls under HS 2933.21?
The primary classification criterion for HS 2933.21 is the presence of an 'unfused imidazole ring' in the chemical structure. This means the imidazole ring must not be fused with other heterocyclic or carbocyclic rings within the same molecule. The 'whether or not hydrogenated' clause indicates that the ring can be fully aromatic or partially/fully saturated (e.g., imidazoline, imidazolidine). Importers and customs brokers must ensure that the chemical's structural formula explicitly shows an unfused imidazole moiety. Compounds where the imidazole ring is fused with another ring system would typically be excluded from 2933.21 and classified elsewhere, often in other subheadings of Chapter 29 or Chapter 30 if pharmaceutical preparations. A Certificate of Analysis (CoA) or a detailed chemical structure diagram is often crucial for accurate classification.
Are there any preferential duty rates or free trade agreements that commonly offer duty-free entry for HS 2933.21?
Yes, many Free Trade Agreements (FTAs) and preferential trade programs offer significantly reduced or duty-free entry for products under HS 2933.21, provided the goods meet the specific Rules of Origin (ROO) of the respective agreement. For example, under the US HTSUS, imports from countries party to agreements such as the USMCA (Mexico, Canada), various FTAs (e.g., Australia, Bahrain, Chile, Colombia, Israel, Jordan, Korea, Morocco, Oman, Panama, Peru, Singapore), and certain preference programs may qualify for 'Free' duty rates. It is imperative for importers to claim these preferential rates by providing valid Certificates of Origin (e.g., USMCA Certificate of Origin, EUR.1 movement certificate) and ensuring the product satisfies the origin requirements of the specific agreement. Failure to meet ROO or provide proper documentation will result in the application of the MFN duty rate.
What specific documentation is typically required by customs authorities for the importation of chemicals under HS 2933.21?
For chemicals classified under HS 2933.21, customs authorities typically require standard import documentation, including a commercial invoice, packing list, and bill of lading or air waybill. Additionally, due to the chemical nature of the product, a Certificate of Analysis (CoA) or a Safety Data Sheet (SDS) is often requested to verify the chemical identity, purity, and composition, which aids in classification and regulatory compliance. If claiming preferential duty rates under a Free Trade Agreement, a valid Certificate of Origin (e.g., EUR.1, GSP Form A, or specific FTA certificate) is mandatory. Depending on the specific compound and its end-use, additional permits or licenses from regulatory bodies (e.g., EPA, FDA in the US; ECHA in the EU) may be required, especially if the substance is controlled or intended for specific applications like pharmaceuticals or pesticides.