Inside the Supply Chain of 2-Chlorophenothiazine: What Buyers Need to Know
I’ve walked a few phenothiazine lines over the years, and this one keeps popping up in procurement calls: [92 39 7]—better known as 2-Chlorophenothiazine. It’s a quiet workhorse, mostly headed into chlorpromazine hydrochloride production. The funny thing is, despite being “just an intermediate,” it now sits at the center of real conversations about quality, traceability, and lead-time. Global pharma doesn’t do “just” anything anymore.
Quick Specs (field notes and buyer essentials)
| Product | 2-Chlorophenothiazine |
| CAS | [92 39 7] (listed as 92-39-7) |
| EINECS | 202-152-5 |
| Molecular formula / weight | C12H8ClNS / 233.72 |
| Appearance | White to grey powder |
| Purity (assay) | ≥98% (HPLC), real-world lots ≈98–99% |
| Application | Intermediate for chlorpromazine HCl |
| Packing | 25 kg/drum (sealed, liner bag) |
| Origin | Xingye Street, Economic & Technological Development Zone, Shijiazhuang, China |
| Shelf life | ≈24 months in unopened drums; store cool, dry, away from light |
Typical range; verify on current COA.
Process Flow, Methods, and Controls
In practice, producers use established aromatic sulfur-bridging chemistry. A common industrial route (I’m simplifying a bit) involves cyclization of chlorinated diphenylamine precursors with sulfur, followed by controlled purification—filtration, solvent swap, and recrystallization. To be honest, the devil is in the drying curve; over-dry and you fight static and dusting, under-dry and you chase moisture specs.
- Materials: chlorinated diphenylamine intermediates, sulfur source, catalytic iodine or similar promoters (varies), class-appropriate solvents.
- Key methods: closed-vessel reaction, staged temperature ramps, carbon treatment (optional), polish filtration.
- Testing: HPLC assay/impurities (per in-house method aligned to ICH), GC residual solvents (ICH Q3C), KF moisture (USP ), ICP-MS heavy metals (ICH Q3D), ID by NMR/IR.
- Standards & systems: ISO 9001 QMS; intermediate-level GMP discipline where customers request it; REACH readiness for EU shipments.
Application Scenarios
Primary: chlorpromazine hydrochloride synthesis (bulk and niche psychiatric formulations). Also, small lots go to medicinal chemistry teams for SAR work—yes, even now—because [92 39 7] offers a reliable scaffold for phenothiazine analog libraries. A few customers mention it behaves nicely in scale-up—predictable filtration, which saves headaches.
Real-World COA Snapshot (illustrative)
Recent batch sample I saw: HPLC assay 98.6%, single-largest impurity 0.35%, moisture 0.20%, residual solvents each ≤500 ppm, total metals ≤10 ppm. Your mileage may vary, but that’s the ballpark buyers tell me they expect for [92 39 7].
Vendor Comparison (what buyers actually check)
| Aspect | KXD Chem (Shijiazhuang) | Regional Trader A | Alt Producer B |
|---|---|---|---|
| Certification | ISO 9001; COA/SDS; REACH-ready docs | Varies; often COA only | ISO 9001 (claimed) |
| Lead time | ≈2–4 weeks ex-works (stock dependent) | Unclear; brokerage delays | 3–6 weeks |
| Customization | Particle size, assay tuning, packaging | Limited | Moderate |
| Documentation depth | Method sheets, impurities map (on request) | Basic | Standard |
Customization & Logistics
- Purity tiers: base 98% with options toward 99% (process-dependent).
- Particle engineering: target d90 or mesh sizing to reduce dust and improve charge-in.
- Packaging: 25 kg fiber drums; small pilots 1–5 kg foil bags; palletization with MSDS labeling.
- Stability: protect from moisture and UV; maintain sealed headspace—service life typically ≈24 months.
Case Notes
One mid-sized API plant reported they cut filtration time 15–20% after switching to a tighter PSD grade of [92 39 7]. Another buyer—R&D heavy—liked that the vendor shared an impurities trend over four quarters. Small things, but they add up when batches roll every week.
Bottom line
If you’re qualifying 2-Chlorophenothiazine, push for a recent COA, method notes, and stress a workable lead-time window. The market is steady, but smart buyers keep a dual-source strategy—just in case.
Authoritative references
- PubChem Compound Summary: 2-Chlorophenothiazine (CAS 92-39-7) — https://pubchem.ncbi.nlm.nih.gov/
- ECHA Brief Profile (substance info, EU) — https://echa.europa.eu/information-on-chemicals
- ICH Q3C (R8) Residual Solvents — https://www.ich.org
- ICH Q3D (R2) Elemental Impurities — https://www.ich.org
- USP General Chapters Water Determination — https://www.usp.org
- ISO 9001:2015 Quality Management Systems — https://www.iso.org/standard/62085.html