SITCSection 5
U.S. imports of heterocyclic compounds with phenothiazine ring system (SITC 51578) totaled $816K in April 2026, traded with 8 countries.
Importers of Heterocyclic Compounds with Phenothiazine Ring System paid $5K in duties in April 2026 — an effective duty rate of 6.5% on $71K in dutiable value, based on actual customs collections rather than the published tariff schedule. Heterocyclic Compounds with Phenothiazine Ring System imports of $816K in April 2026 ran 18% below the year-to-date monthly average of $997K.
Last updated: April 2026 dataPhenothiazine ring-system compounds — tricyclic structures containing both sulfur and nitrogen heteroatoms — are the chemical backbone of a historically important class of antipsychotic drugs, including chlorpromazine and thioridazine, as well as veterinary antiparasitic agents and industrial antioxidants. The 'not further fused' qualifier limits this subheading to the core phenothiazine tricycle; compounds where additional rings are appended to that system fall outside the category. Despite the decline of first-generation phenothiazine antipsychotics in clinical practice, the scaffold remains relevant in agrochemical and materials chemistry.
AI-written summary of the official U.S. Census Bureau trade figures on this page — verify before relying on it.
Phenothiazine is specifically a tricyclic system with two benzene rings bridged by both a sulfur atom and a nitrogen atom. Other sulfur-containing heterocyclics — such as thiophene (monocyclic) or thioxanthene (no nitrogen) — classify under different headings. The presence of both S and N within the same fused tricyclic core is the defining structural feature.
Phenothiazine itself is used as a polymerization inhibitor in the production of vinyl monomers such as styrene and acrylic acid, and as an antioxidant additive in lubricants and rubber. These industrial applications make it a dual-use chemical traded by both the chemical process industry and pharmaceutical supply chains.
| Country | Imports | Exports | Balance |
|---|---|---|---|
| GERMANY | $426K | $3K | -$423K |
| CHINA | $361K | -- | -$361K |
| INDIA | $29K | $5K | -$24K |
| UNITED KINGDOM | -- | $7K | +$7K |
| TAIWAN | -- | $5K | +$5K |
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Monthly import values over time