4.5.6.7-Tetrahydrothiophene[3.2.0] Pyridine Hydrochloride, usually appearing as a crystalline solid, has found its way into a surprising range of research labs and manufacturing spaces. With its unusual sulfur and nitrogen bridged core, this molecule stands apart from simpler aromatic hydrochlorides or plain heterocyclic compounds. Its hydrochloride salt form typically presents as fine white or slightly off-white flakes or powder. This unique structure gives it a combination of basic and slightly sulfurous properties, setting it apart from more familiar pyridine derivatives. I’ve watched chemists reach for this compound in syntheses where a balance of nucleophilicity and stability is key, especially in novel pharmaceutical or catalytic applications.
This hydrochloride stands out structurally because of the fusion of a six-membered thiophene ring with a pyridine core, bridged to create a [3.2.0] bicyclic framework. Such a configuration doesn’t come from traditional benzene ring chemistry, so it resists the expectations folks usually bring to the table with heterocycles. The hydrochloride portion increases solubility in water and certain polar organic solvents, making it less volatile and easier to manage in both solution and solid applications. Most samples land with a specific density ranging between 1.18 and 1.25 grams per cubic centimeter, sometimes appearing in pearl, crystalline solid, or fine powder forms. The chemical moves between acting as a raw material for downstream syntheses and functioning as a chemical intermediate in more sophisticated procedures.
Exact batch specifications matter. Typical analysis reports put its purity at 97% or higher, while moisture content rarely creeps above 0.5%. Commercial containers run from 100-gram glass bottles all the way up to kilogram-labeled drums. If you get a solid block, it flakes easily under gentle pressure; as a powder, it clusters finely without excessive clumping. The empirical formula for 4.5.6.7-Tetrahydrothiophene[3.2.0] Pyridine Hydrochloride sits at C7H11NS·HCl, with a molar mass of about 179.7 g/mol. Visual cues like white to pale yellow crystalline powder tell you if the batch has taken on moisture or degraded, which anyone working with sensitive reagents learns to check right away.
The backbone runs: C7H11NS·HCl. A quick search using this formula deletes confusion when ordering new material, since names get long, and typos appear more often than you’d expect. Its CAS Registry Number—like a chemical’s personal ID—locks in the reference, so everyone from the warehouse crew to the bench chemist avoids mix-ups.
International shipping usually codes this hydrochloride under HS 2934 (heterocyclic compounds), with each subcategory narrowing based on end use and purity. This coding means border agents and customs labs know exactly what’s entering, often marking it for specific control if it can be routed into pharmaceutical or technical chemical processes. Knowing the HS code does more than prevent paperwork headaches—it decides duties, import timing, and packaging choices. Keeping the right paperwork together speeds up clearance and keeps costs contained on both sides of the supply chain.
Lab workers recognize this hydrochloride by its smell, which sometimes hints at sulfur on top of classic pyridine sharpness. The solid form can be dense flakes, granular pearls, or powder. These forms pack differently, affecting drying, weighing, and solution prep. For larger-scale operations, packaging must resist humidity and light, preserving the integrity of the contents. Folks often dissolve it in methanol, ethanol, or water at liter scales to whip up stock solutions for reactions or further transformation, noting any cloudiness or precipitation as a sign of impurity or over-concentration.
From my own time in labs, respect for hazardous materials means understanding the risks behind every label. 4.5.6.7-Tetrahydrothiophene[3.2.0] Pyridine Hydrochloride deserves handling as a potentially harmful material. While not volatile enough to make a room smell after a quick spill, skin contact and accidental inhalation should be avoided. Material safety data (SDS) notes acute toxicity in case of large-scale exposure, irritation on contact, and a need for local exhaust ventilation in enclosed spaces. Proper lab practice keeps it in tightly sealed, chemical-resistant bottles, labelled clearly and stored away from oxidizers or strong bases. Anyone using this chemical in an academic or industrial context needs goggles, gloves, and reliable ventilation, as it behaves like many moderate-risk, organosulfur intermediates.
What separates this molecule from generic heterocycles is its flexibility in synthetic chemistry. Researchers use it as a raw material feedstock, connecting complex synthesis steps that wouldn’t work with standard pyridines or thiophenes. Some pharmaceutical researchers explore it as a building block for new active molecules. Catalysis studies sometimes highlight it as a source of structural motifs that resist breakdown under tough conditions. This means a supply chain built on reliable quality and clear documentation matters.
The biggest challenge comes down to purity and consistency. Impurities can torpedo a multi-step synthesis or cause failed reactions at scales much larger than the average test tube. One solution I’ve seen work well involves setting up close supplier relationships, securing material with third-party certification that matches the required analysis. Storage must keep moisture away, and frequent batch testing with routine titration or chromatography keeps surprises to a minimum. Waste handling guidelines treat all residuals as hazardous, due to both the hydrochloride and sulfur components, requiring safe neutralization before disposal. In my own lab experience, this extra diligence might slow things down, but results always justify the effort.
