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SITCSection 5
U.S. imports of heterocyclic compounds with nitrogen hetero-atoms only (nes) (SITC 51577) totaled $131.0M in July 2026, traded with 40 countries.
Importers of Heterocyclic Compounds with Nitrogen Hetero-Atoms Only (NES) paid $3.3M in duties in July 2026 — an effective duty rate of 7.3% on $44.8M in dutiable value, based on actual customs collections rather than the published tariff schedule.
Last updated: July 2026 dataNitrogen-only heterocyclic compounds not elsewhere specified represent the residual catch-all for ring systems — such as azepines, diazines not covered by pyrimidine headings, and multi-nitrogen scaffolds — that do not fit any of the more specifically enumerated nitrogen-heterocycle subheadings. Because this is a residual category, classification here requires a process of elimination: the compound must be confirmed as not classifiable under pyrazole, imidazole, pyridine, quinoline, pyrimidine, piperazine, triazine, or phenothiazine headings. Many novel pharmaceutical scaffolds and agrochemical candidates land here during early-stage API development.
AI-written summary of the official U.S. Census Bureau trade figures on this page — verify before relying on it.
1.1K shipments/mo
Basic heading 27 of 465 in section 5
Basic heading 51577 · $131.0M of $28.9B
The classifier should work through each named nitrogen-heterocycle subheading in order — pyrazole, hydantoin, imidazole, pyridine, quinoline, pyrimidine/piperazine/triazine, and phenothiazine — and confirm the compound's ring system does not match any of them. Only after ruling out all named categories should the compound be placed in the NES subheading. A licensed customs broker with fine-chemical expertise is advisable for novel or complex structures.
Many nitrogen heterocyclic intermediates sourced from China fall within HTS chapters subject to Section 301 tariffs, and the NES category is no exception. Because this is a residual grouping covering diverse structures, the applicable 10-digit HTS code — and its Section 301 status — must be verified for each specific compound before importation.
Supplier Network
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Imports · July 2026
origin
Ireland and Spain together supply 49% of it.
customs district
Census does not publish district detail for this classification system.
destination
Census does not publish state detail for this classification system.
entry
Census does not publish port detail for this classification system.
ImportsExports
Imports
$131.0MYoY · Pro
Exports
$22.8MYoY · Pro
12-mo low · imports
YoY · ProThrough July 2026. Source: U.S. Census Bureau.