Heterocyclic compounds with nitrogen hetero-atom — HTS 2933
Heterocyclic compounds with nitrogen hetero-atom(s) only
Chapter 29 › Heading 2933
2026 HTS Rev 19 Synced Rules verified Operational
Written to help non-specialists understand this page. Rates, dates, and legal facts come from the official records above and on the linked source.
HTS heading 2933 is a broad product category for organic chemical compounds whose ring structure is heterocyclic and contains one or more nitrogen atoms as the only hetero-atoms. A heterocyclic compound has a ring made from atoms, with at least one ring atom being something other than carbon; under this heading, the non-carbon ring atoms are nitrogen. The heading can cover many different chemical substances, but it does not by itself identify the exact product or duty treatment.
To reach the correct 8-digit HTSUS code, start with the product’s chemical identity and then follow the more specific subheadings and statistical subdivisions under heading 2933. These subdivisions commonly distinguish the compound by its named chemical type, molecular structure, functional groups, or whether it falls within a residual “other” provision. Use the product’s Chemical Abstracts Service (CAS) number, molecular formula, structural formula, purity, and technical description to compare it with the wording of each candidate provision. Classification may require a customs broker or qualified chemical-classification professional, especially for mixtures, derivatives, formulations, or products with multiple possible descriptions.
What to check
- Confirm that the product is a single chemical compound, or determine whether it is a mixture, solution, formulation, or preparation that may require different classification analysis.
- Obtain the exact chemical name, CAS number, molecular and structural formulas, composition, purity, and safety data sheet from the manufacturer.
- Check the heading’s legal notes, subheading descriptions, and any chapter or section notes before selecting an 8-digit statistical subdivision.
- Compare the compound’s ring structure and nitrogen-containing heterocycle with every specifically named provision before using an “other” category.
- Verify the proposed code against current official HTSUS materials and seek customs-broker or chemical-classification advice when the structure or product form is unclear.
HTS heading 2933 summary
Heterocyclic compounds with nitrogen hetero-atom is a 4-digit product category containing 17 published product-code lines in this snapshot. A heading does not carry one universal duty rate; classification must be narrowed to the line matching the product facts.
How to find your code in this category
A heading is a product category. To get the exact duty, narrow from this 4-digit heading to a sub-category (usually by material), then open the 8-digit code that matches your product.
Open any code in the tables below to see its exact duty rate, a duty calculator (enter your shipment value → estimated duty and landed cost), the rate-change history chart, and the country-by-country breakdown (including Section 301/232 add-on duties).
Why you have to click in: a single category can contain products with very different duties. The rate depends on the specific product — its material and construction — and on the country of origin, and those only get pinned down at the 8-digit code level. That is why this page points you to codes instead of showing one rate for the whole category.
Sub-categories
| Code | Description |
|---|---|
| 2933.19 | Other |
| 2933.29 | Other |
| 2933.32 | Piperidine and its salts |
| 2933.39 | Other |
| 2933.49 | Other |
| 2933.52 | Malonylurea (Barbituric acid) and its salts |
| 2933.59 | Other |
| 2933.69 | Other |
| 2933.79 | Other lactams |
| 2933.99 | Other |
Product codes & duty rates
👇 Each row is a specific product code — click a blue code to open its full page with exact duty rates by country, the rate-history chart, and a duty calculator. 👉
| Code | Description | General (MFN) | Special | Column 2 |
|---|---|---|---|---|
| 2933.11.00.00 👉 | Phenazone (Antipyrine) and its derivatives | 6.5% | Free | 15.4¢/kg + 49.5% |
| 2933.21.00.00 👉 | Hydantoin and its derivatives | 6.5% | Free | 15.4¢/kg + 63% |
| 2933.31.00.00 👉 | Pyridine and its salts | Free | — | Free |
| 2933.33.01.00 👉 | Alfentanil (INN), anileridine (INN), bezitramide (INN), bromazepam (INN), carfentanil (INN), difenoxin (INN), diphenoxylate (INN), dipipanone (INN), fentanyl (INN), ketobemidone (INN), methylphenidate (INN), pentazocine (INN), pethidine (INN), pethidine (INN) intermediate A, phencyclidine (INN) (PCP), phenoperidine (INN), pipradrol (INN), piritramide (INN), propiram (INN), remifentanil (INN) and trimeperidine (INN); salts thereof | Free | — | 15.4¢/kg + 149.5% |
| 2933.34.00.00 👉 | Other fentanyls and their derivatives | 6.5% | Free | 15.4¢/kg + 52% |
| 2933.35.00.00 👉 | 3-Quinuclidinol | 5.8% | Free | 15.4¢/kg + 39.5% |
| 2933.36.00.00 👉 | 4-Anilino-N-phenethylpiperidine (ANPP) | 6.5% | Free | 15.4¢/kg + 52% |
| 2933.37.00.00 👉 | N-Phenethyl-4-piperidone (NPP) | 6.5% | Free | 15.4¢/kg + 52% |
| 2933.41.00.00 👉 | Levorphanol (INN) and its salts | Free | — | 15.4¢/kg + 67.5% |
| 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 | Free | — | 50% |
| 2933.54.00.00 👉 | Other derivatives of malonylurea (barbituric acid); salts thereof | 3.7% | Free | 50% |
| 2933.55.00.00 👉 | Loprazolam (INN), mecloqualone (INN), methaqualone (INN) and zipeprol (INN); salts thereof | Free | — | 15.4¢/kg + 149.5% |
| 2933.61.00.00 👉 | Melamine | 3.5% | Free | 25% |
| 2933.71.00.00 👉 | 6-Hexanelactam (ε-Caprolactam) | 6.5% | Free | 15.4¢/kg + 40% |
| 2933.72.00.00 👉 | Clobazam (INN) and methyprylon (INN) | Free | — | 15.4¢/kg + 52% |
| 2933.91.00 👉 | Alprazolam (INN), camazepam (INN), chlordiazepoxide (INN), clonazepam (INN), clorazepate, delorazepam (INN), diazepam (INN), estazolam (INN), ethyl loflazepate (INN), fludiazepam (INN), flunitrazepam (INN), flurazepam (INN), halazepam (INN), lorazepam (INN), lormetazepam (INN), mazindol (INN), medazepam (INN), midazolam (INN), nimetazepam (INN), nitrazepam (INN), nordazepam (INN), oxazepam (INN), pinazepam (INN), prazepam (INN), pyrovalerone (INN), temazepam (INN), tetrazepam (INN) and triazolam (INN); salts thereof | Free | — | 15.4¢/kg + 149.5% |
| 2933.92.00.00 👉 | Azinphos-methyl | Free | — | 15.4¢/kg + 64.5% |
"Special" shows the free-trade-agreement rate; open a code to see exactly which countries qualify.
Common questions
What products fall under HTS heading 2933?
Heterocyclic compounds with nitrogen hetero-atom(s) only. To classify a specific item you must pick the matching sub-category and 8-digit code above; the right choice usually depends on the material and construction of the product.
How do I choose the right code within this category?
Start from the sub-categories (typically divided by material—for example cotton versus man-made fibers), then open the active 8- or 10-digit code that matches the product. When unsure, a licensed customs broker or a CBP binding ruling can confirm the classification.
Reference information only, not customs, legal, or classification advice. Confirm the current code and rate against the official HTS before you import.