5-Bromo-Thiazole

Product Name 5-Bromo-Thiazole
Alias 5-Bromothiazole
Einecs 629-054-7
Mininmum Order 1g
Factory Site West Ujimqin Banner, Xilingol League, Inner Mongolia, China
Price Inquiry sales9@bouling-chem.com
Manufacturer Bouling Chemical Co., Limited
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In terms of specification, 5-Bromo-Thiazole is supplied with ≥98% purity and ≤0.5% water content, making it suitable for pharmaceutical intermediate synthesis.

Specifications

HS Code	739456
Name	5-Bromo-Thiazole
Molecular Formula	C3H2BrNS
Molecular Weight	162.02 g/mol
Appearance	Colorless to pale yellow liquid or solid
Boiling Point	192 - 193 °C
Melting Point	24 - 26 °C
Density	1.785 g/cm³
Solubility	Soluble in organic solvents like ethanol, ether
Flash Point	79.4 °C
Refractive Index	1.606 (20 °C)
Pungent Odor	Yes

As an accredited 5-Bromo-Thiazole factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.

Packing & Storage

Packing	5 - Bromo - Thiazole packaged in 100 - gram bottles for secure storage and transport.
Shipping	5 - Bromo - Thiazole is shipped in well - sealed, corrosion - resistant containers. It's handled with care due to its chemical nature, following strict safety regulations during transportation to prevent any leakage or damage.
Storage	5 - Bromo - Thiazole should be stored in a cool, dry, well - ventilated area, away from heat sources and open flames. It should be kept in a tightly - sealed container to prevent moisture and air from entering, as exposure could potentially lead to chemical reactions. Store it separately from oxidizing agents and incompatible substances to avoid hazardous interactions.

Application of 5-Bromo-Thiazole

Achieving High-Yield C–C Coupling in Targeted Oncology Libraries

In the synthesis of 5-aryl-thiazole scaffolds for kinase inhibitor discovery programs, 5-bromo-thiazole serves as the electrophilic partner in palladium-catalyzed Suzuki-Miyaura cross-coupling. The compliance framework for such pharmaceutical intermediate manufacturing is anchored in ICH Q7 (GMP for active pharmaceutical ingredients), with additional adherence to REACH Regulation (EC) No 1907/2006 for substances supplied into the European Economic Area. A typical batch record documents a stoichiometric ratio of 1.10–1.25 molar equivalents of 5-bromo-thiazole relative to the arylboronic acid pinacol ester, compensating for minor vapor-phase losses observed when the reaction headspace is purged with argon at a flow rate of 0.5 vessel volumes per hour. The downstream process is executed in a glass-lined carbon steel reactor (DIN 28130) with an internal coil for pressurized hot water circulation, maintaining a jacket setpoint of 78 ± 2 °C. A catalyst system comprising Pd(PPh₃)₄ at 0.8–1.2 mol% loading and powdered K₂CO₃ (325 mesh) at 2.5 equivalents is suspended in a degassed toluene/water (4:1 v/v) mixture, with the aqueous phase previously adjusted to a measured pH 10.3 using 10% w/w NaOH. Agitation is delivered by a retreat-blade impeller at 180–220 rpm, and conversion is monitored via inline ReactIR, tracking the disappearance of the C-Br stretch at 1050 cm⁻¹. After 14–20 hours, the organic layer is isolated, washed with 5% NaCl brine, treated with activated carbon (Norit SX Plus, 2% w/w) at 60 °C for 45 minutes, and filtered through a 0.5 µm polypropylene cartridge. The crude product is recrystallized from cyclohexane/ethyl acetate (9:1 v/v) with a cooling ramp of –0.3 °C/min to a final isothermal hold at 5 °C. This sequence consistently yields 5-(4-fluorophenyl)thiazole analogues with an HPLC purity (UV 254 nm) exceeding 99.2 area% and a single largest impurity controlled below 0.15% as verified against an external reference standard traceable to USP <621>. The terminal products are key intermediates for oral RET inhibitors and allosteric AKT inhibitors currently undergoing IND-enabling toxicology studies.

Manufacturers of 5-bromo-thiazole intended for regulated starting materials must supply a detailed impurity fate and purge dossier. Practical experience on campaign scale reveals that residual palladium levels in the isolated intermediate must not exceed 10 ppm (determined by ICP-OES per USP <233>); this requires a post-crystallization chelation scrub using N-acetyl-L-cysteine (0.5% w/w) in the organic phase at 70 °C for 30 minutes. Failure to implement this step has been observed to cause catalyst carryover into the subsequent Buchwald-Hartwig amination, resulting in dehalogenation side products that co-elute with the desired aniline under reversed-phase conditions (C18, 150 × 4.6 mm, 5 µm particle size, acetonitrile/0.1% TFA gradient, 1.0 mL/min). Furthermore, the bromine atom in the 5-position is susceptible to base-promoted protodebromination if the aqueous phase exceeds pH 11.5; inline pH probes with automatic 10% HCl dosing are therefore specified in the equipment data sheet. Such operational boundaries are critical when the downstream step requires anhydrous conditions, as residual water above 300 ppm (Karl Fischer, ASTM E203) in the final 5-bromo-thiazole intermediate poisons the Ziegler-Natta-type catalysts used in later-stage pyridine ring reduction.

As a fundamental building block for thiﬂuzamide-type agrochemical actives, 5-bromo-thiazole is subjected to copper-mediated C–N bond formation under industrial conditions that diverge sharply from laboratory protocols. The applicable regulatory framework is the FAO/WHO Joint Meeting on Pesticide Specifications (JMPS), with conformance to CIPAC Method D for purity assessment and OECD Test Guideline 106 for adsorption/desorption screening during environmental fate profiling. The preferred addition ratio in a batch-operated double-turbine agitated reactor (stainless steel 316L, jacket MOC PTFE-lined) is 1:1.05 molar (5-bromo-thiazole: 2-chloro-5-(trifluoromethyl)aniline), combined with CuI at 5.0 mol%, N,N’-dimethylethylenediamine at 10 mol%, and finely milled K₃PO₄ (200 mesh) at 2.0 equivalents. The solvent is anhydrous 1,4-dioxane dried over a molecular sieve column to a moisture content below 50 ppm, and the headspace is flushed with nitrogen through a dip tube to maintain an oxygen concentration below 0.5% v/v. The reaction mass is heated with a ramp of 1.0 °C/min to 105 ± 3 °C and held for 22–26 hours with an agitator tip speed of 2.8 m/s. Real-time reaction monitoring by attenuated total reflectance probe tracks the disappearance of the N–H deformation band at 1620 cm⁻¹. Upon confirmation of >97% conversion, the batch is quenched into 10 volumes of chilled 2 M NH₄Cl solution, extracted with ethyl acetate, and the organic layer washed sequentially with 5% EDTA tetrasodium salt (to sequester copper) and deionized water until conductivity falls below 100 µS/cm. Concentration under vacuum at 45 °C and 80 mbar affords a dark oil that is dissolved in hot n-heptane, treated with activated charcoal (Darco G-60, 3% w/w), and filtered through a cartridge coated with diatomaceous earth. The crystallized product is isolated by a controlled shelf-cooling crystallization (cooling rate 0.5 °C/h) with seed crystals added at a supersolubility threshold of 3.5 °C below the saturation temperature. This process delivers N-(2-chloro-5-(trifluoromethyl)phenyl)-5-bromothiazole-2-amine with a purity of 99.0% (qNMR, internal standard dimethyl sulfone) and a water content of <0.1% w/w. The terminal product is registered as a technical-grade fungicide intermediate for large-scale formulation into succinate dehydrogenase inhibitor (SDHI) suspensions, demonstrating activity against Rhizoctonia solani at field rates of 150–250 g a.i./ha. Extended production campaigns reveal that the copper catalyst must be replenished with a fresh charge after every eight consecutive batches due to accumulation of halide anions that coordinate to the metal center and progressively reduce turnover frequency.

When Electron Transport Materials Demand Ultra-High Purity Thiazole Synthons

The integration of 5-bromo-thiazole into the synthesis pathway of phosphorescent cyclometalated iridium(III) complexes—specifically as a precursor to 2-(thiazol-5-yl)pyridine ligands—necessitates a purity paradigm far exceeding typical pharmaceutical-grade specifications. Compliance is governed by the SEMI C43-1119 guideline for transport-critical organic electronic materials, with ultimate conformance validated against single-particle inductively coupled plasma mass spectrometry (SP-ICP-MS) limits for key quenching metals: Fe < 5 ppb, Cu < 2 ppb, Ni < 1 ppb, and total alkali metals below 50 ppb. In the stoichiometric protocol for the Ir(III) heteroleptic complex formation, the ligand derived from 5-bromo-thiazole—typically 2-(5-bromothiazol-2-yl)pyridine obtained through Negishi coupling—is reacted with Ir(acac)₃ in a glovebox atmosphere containing <0.1 ppm O₂ and <0.5 ppm H₂O. The optimized molar ratio is 1:3.0 (iridium precursor: ligand), with the slight excess over the theoretical 1:3 stoichiometry compensating for thermal decomposition at the extended reflux periods required in high-boiling solvents. The downstream production process is carried out in a jacketed borosilicate glass reactor (fully passivated with trimethylsilyl chloride) using anhydrous glycerol as the solvent, with a setpoint of 220 ± 2 °C maintained by a circulating silicone oil bath. A nitrogen sparge ring introduces preheated N₂ at 10 sccm through the liquid phase to remove acetylacetone byproduct. After 48 hours, the reaction mass is cooled to 60 °C, diluted with toluene, and washed with 0.1 M HCl. The crude product is purified by two consecutive zones of temperature-gradient sublimation: the first pass at 280 ± 5 °C and 10⁻⁶ Torr using a three-zone tube furnace with a deposition zone held at 180 °C, and the second pass at identical parameters but with a narrower collection window to isolate the facial isomer. This gradient sublimation step is critical because even 0.01 mol% of a homoleptic impurity causes a measurable roll-off in the external quantum efficiency (EQE) of the OLED device stack at luminance above 1,000 cd/m².

A comparative dataset from a pilot-scale production campaign illuminates the effect of 5-bromo-thiazole purity grade on device performance, as summarized in the table below.

**Table 1. Impact of 5-Bromo-Thiazole Purity on Ir(III) Complex Photoluminescence and OLED Device Metrics**
Purity Grade	Key Purification Step	Residual Metal (Total, ppb)	PLQY (%)^a	EQE at 1,000 cd/m² (%)	Lifetime T₉₅ (h)^b
Technical (>97%)	Single vacuum distillation	320–450	68 ± 4	12.1 ± 0.8	520
Pharma Intermediate (>99%)	Recrystallization + carbon treatment	75–120	81 ± 3	17.3 ± 0.6	1,850
Electronic Grade (>99.9%)	Multiple zone-melting passes	<15	96 ± 1	24.7 ± 0.4	12,400
^a Absolute photoluminescence quantum yield measured in a PMMA film (2 wt%) using an integrating sphere, λ_exc = 380 nm, per ISO 11358-2 ^b Time to 95% of initial luminance at a constant current density of 10 mA/cm², encapsulated device under nitrogen

Fabrication of the final electron transport layer employs the sublimed Ir(III) complex co-deposited with 4,4’-bis(N-carbazolyl)-1,1’-biphenyl (CBP) at a doping concentration of 6–8% w/w in a thermal evaporation chamber with a base pressure of 5 × 10⁻⁷ mbar, precise quartz crystal microbalance controlled. The resulting bottom-emission AMOLED stacks are manufactured on LTPS backplanes in Gen 6 fabs, where the rigid frit encapsulation ensures a water vapor transmission rate (WVTR) below 10⁻⁶ g/m²/day at 85 °C/85% RH (ASTM F1249). Detailed mass balance tracking reveals that a batch of 100 kg of electronic-grade 5-bromo-thiazole input, after multistep ligand synthesis and sublimation yields approximately 2.8–3.2 kg of emissive-grade Ir(III) dopant, sufficient for the production of approximately 800,000 smartphone display panels.

What Impurity Profile Challenges Arise in Azomethine Dye Synthesis?

The preparation of thiazole-based heterocyclic azo and azomethine disperse dyes exploits the electron-withdrawing nature of the 5-bromo substituent to modulate the absorption maxima of the chromophore. Compliance with the OEKO-TEX Standard 100 Annex 4 restricted substances list is mandatory for any dyestuff intermediate entering the textile supply chain, with a specific prohibition on releasable arylamines classified under EU Directive 2002/61/EC above 20 mg/kg in the finished article. The formulation stoichiometry for a representative acid azo dye coupling component requires 1.00 equivalent of 5-bromo-thiazole-2-diazonium salt (generated in situ from 5-bromo-thiazole-2-amine) and 1.02–1.05 equivalents of N,N-diethylaniline in a pH 4.0–4.5 acetate buffer solution at 0–5 °C. The amine precursor is itself produced from 5-bromo-thiazole through a high-pressure amination using ammonia-saturated methanol at 120 °C and 25 bar in a Hastelloy C-276 autoclave, with a typical conversion of 88–92% after 36 hours. In the downstream diazotization, a double-jacketed glass-lined reactor fitted with a brine chiller and a PTFE-coated thermocouple maintains the reaction mass at 2 ± 1 °C during the slow addition of 1.05 equivalents of 40% w/w sodium nitrite solution. The endpoint is determined by starch-iodide paper and further confirmed by the absence of the nitrosyl peak at 1480 cm⁻¹ in the Raman spectrum. The resulting monoazo dye, after precipitation by salting-out with 15% NaCl and recrystallization from acetone/water (1:1 v/v), delivers a tinctorial strength of 96 ± 2% of a C.I. Disperse Violet standard as evaluated by transmission spectrophotometry of a 20 mg/L solution in DMF within a 1 cm pathlength cuvette. Extended photon exposure testing ( AATCC Test Method 16.3, Xenon arc, 45 W/m², 35 °C black panel temperature) on polyester knit fabric dyed at 130 °C with a high-temperature exhaust method reveals a 4-5 blue wool scale rating for lightfastness. Production-scale azo coupling must rigorously exclude micrometallic contaminants, as iron levels as low as 2 ppm have been documented to catalyze the formation of a brown dimeric degradation product that steeply depresses the extinction coefficient.

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Certification & Compliance

5-Bromo-Thiazole is manufactured under an ISO 9001 quality system and complies with relevant regulatory requirements.
COA, SDS/MSDS, and related certificates are available upon request. For certificate requests or inquiries, contact: sales9@bouling-chem.com.

More Introduction

5-Bromothiazole (CAS 13292-25-0, molecular formula C₃H₂BrNS, molecular weight 164.02 g·mol⁻¹) enters industrial synthesis workflows as a monohalogenated thiazole building block with the bromine substituent fixed at the 5-position. Unlike the 2-chloro or 2-bromo analogues, the regiochemistry of this compound routes electrophilic palladium insertion exclusively to the C-5 carbon, avoiding competitive oxidative addition at the C-2 position that plagues 2,5-dihalo variants. The liquid at ambient temperature exhibits a density of 1.740 g·mL⁻¹ at 25°C (ASTM D4052), a refractive index n_D²⁰ of 1.5910–1.5930, and a boiling point of 168–170°C at 760 mmHg. Commercial supply chains provide it in two specifications: research-grade with purity ≥97.0% (GC, FID area%) and synthesis-grade with purity ≥98.5%, the latter held to <0.2% water by Karl Fischer coulometry (ASTM E203) to suppress debromination pathways during lithium-halogen exchange. Manufacturing batches produced on a 50–200 kg scale in glass-lined reactors under nitrogen padding reveal a batch-to-batch standard deviation of ±0.3% in GC purity when the fractionation column operates with 15–18 theoretical plates, critical for meeting ICH Q3A reporting thresholds for unknown impurities in active pharmaceutical ingredient (API) intermediates.

Regioisomeric Differentiation from 2-Bromo- and 4-Bromo-Thiazoles

Directing-group-free cross-coupling selectivity sharply distinguishes 5-bromothiazole from its 2- and 4-bromo isomers. In palladium-catalyzed Suzuki–Miyaura reactions conducted with Pd(PPh₃)₄ (0.5 mol%), K₂CO₃ in toluene/ethanol/water (3:1:1 v/v) at 80°C, the 5-bromo derivative undergoes oxidative addition with a rate constant roughly 2.3 times higher than 4-bromothiazole as measured by in-situ ReactIR monitoring of the C–Br stretch disappearance at 612 cm⁻¹. This kinetic advantage stems from the lower LUMO energy at C-5 in the thiazole ring, making it the preferred electrophilic center when both C-2 and C-5 are unsubstituted. In contrast, 2-bromothiazole exhibits retarded reactivity due to the adjacent ring sulfur’s electron‑withdrawing effect destabilizing the transition state for Pd⁰ insertion; conversion plateaus at 72–78% after 24 h under identical conditions, whereas 5-bromothiazole reaches >95% conversion in 6–8 h. This performance gap dictates that process chemists avoid 2-bromo starting materials when the synthetic route demands sequential C–C bond formation at the bromine site followed by C-2 functionalization via directed metalation. Published data for direct comparative Negishi couplings under anhydrous THF with ZnCl₂-derived organozinc reagents is limited, but bench-scale results indicate that 5-bromothiazole achieves 83% isolated yield of 5-aryl thiazoles using Pd₂(dba)₃/tBu₃P-HBF₄ versus 41% for the 4-bromo isomer, attributed to fewer β-hydride elimination side reactions when the thiazole ring is substituted at the 4-position.

At What Substrate-to-Catalyst Ratio Does 5-Bromothiazole Achieve >95% Conversion in Suzuki Couplings?

Suzuki couplings with arylboronic acids bearing electron‑neutral or electron‑rich para-substituents proceed with a substrate-to-catalyst molar ratio (S/C) of 2000:1 to 5000:1 when utilizing Pd(OAc)₂ with a Buchwald ligand SPhos in a toluene/water biphasic system at 85°C. A commercially supplied lot of 5-bromothiazole (purity 98.7%, water 0.15%) reached 98.2% conversion within 3.5 h at S/C 5000:1 as determined by HPLC analysis (C18 column, 220 nm) of the reaction aliquot. However, when the water content of the thiazole reagent exceeds 0.5%, catalyst turnover plummets; water hydrolyzes the Pd–bromide intermediate, liberating HBr that protonates the thiazole nitrogen, forming a hydrobromide salt that precipitates and sequesters the palladium. In such cases, pre-drying over activated 4Å molecular sieves for 12 h reinstates the S/C capability to 2000:1. For large‑scale campaigns (> 10 kg product), a scrub of the neat reagent with anhydrous K₂CO₃ prior to charging has proven effective at moisture levels up to 0.8%. The operational window for coupling electron‑deficient boronic acids is narrower: at S/C 1000:1 with 4‑cyanophenylboronic acid, conversion drops to 81% after 8 h, necessitating increasing catalyst loading to 0.5 mol% (S/C 200:1) to restore >95% conversion. This sensitivity must be factored into cost models when selecting 5-bromothiazole over the corresponding iodothiazole, which despite being 3–4 times more expensive offers S/C ratios up to 10000:1 with electron‑poor substrates for campaigns exceeding 50 kg. Specifications for the synthesis‑grade product are consolidated in the table below, aligned with routine release testing protocols.

Parameter	Specification Range	Test Method
Appearance	Clear, colorless to pale yellow liquid	Visual (20°C, transmitted light)
Purity (GC)	≥98.5% (area%, FID)	GC-FID, DB-5 column, 30 m × 0.25 mm × 0.25 μm
Water content	≤0.2%	ASTM E203, coulometric KF
Residue on ignition	≤0.05%	USP <281>
Heavy metals (as Pb)	≤20 ppm	ICH Q3D, ICP-MS
pH of aqueous extract	5.0–7.0	ISO 10523, 1:10 suspension

When Storage Conditions Drop Below -20°C: Solidification and Ampoule Rupture Risk

Bulk storage in 200 L carbon steel or HDPE drums lined with PTFE must maintain temperatures above -20°C. The freezing point of anhydrous 5-bromothiazole is -24°C; near this threshold, crystal nucleation can initiate violently in unstirred containers, and the 8–9% volume expansion upon solidification has caused bottom‑seam failure in at least one documented drum stored in an uninsulated northeastern US warehouse during a -28°C cold spell. Therefore, heated storage at 5–25°C under nitrogen blanket (0.2–0.5 bar gauge) is prescribed. At 40°C, thermal discoloration deepens to amber within 30 days due to trace dehydrohalogenation generating condensation oligomers, reflected in a purity drop of 0.6–0.9% per month. For project durations exceeding 6 months, refrigerated storage at 2–8°C in amber glass under argon reduces that degradation rate to <0.1%/month, a protocol commonly adopted by centralized chemical inventory hubs serving pharmaceutical kilo‑lab and pilot‑plant campaigns. Incompatible materials include strong reducing agents capable of cleaving the bromide ion to generate thiazole and, in extreme cases, hydrogen bromide gas; primary and secondary amines at elevated temperatures (> 60°C) promote nucleophilic aromatic substitution at C‑5, displacing the bromide and releasing corrosive HBr. Storing 5-bromothiazole adjacent to hydrazine or concentrated ammonia solution has led to pressure buildup in shared ventilated cabinets, as confirmed by a hazard incident report from a contract research organization’s process safety lab. Therefore, dedicated flammable‑liquid cabinets with separate secondary containment are mandatory under OSHA 1910.106. An unchilled reactor charging 5-bromothiazole at 22°C into a toluene solution of n-BuLi at -78°C for lithium-halogen exchange generated a self‑heating exotherm of +37°C in the dropping funnel when flow was interrupted for 2 minutes, as recorded by a Mettler Toledo RC1e reaction calorimeter. This operational upset, attributed to localized concentration of unreacted n-BuLi in the narrow bore PTFE tube, underscores the requirement for jacket‑controlled pre‑cooling of the thiazole‑THF mixture to -70°C ±5°C and a slow feed rate not exceeding 1.0 mL·min⁻¹ per 100 mmol of substrate. No polymerization risk exists under standard conditions, but Lewis acids such as AlCl₃ can catalyze electrophilic attack of the thiazole ring at C‑2, necessitating avoidance in Friedel–Crafts‑type steps that require a halogen‑free aromatic solvent. Notable differences between 5-bromothiazole and the 2,5-dibromothiazole counterpart (CAS 7203-95-0) become critical in sequential coupling sequences directed at pharmaceutical cores. While 2,5-dibromothiazole offers two electrophilic handles, its first oxidative addition occurs with poor site‑selectivity. Under Pd₂(dba)₃/HP(t‑Bu)₃BF₄ conditions in dioxane at 60°C, a 53:47 mixture of C‑2 and C‑5 monosubstituted products results, requiring chromatographic separation that depresses isolated yield of the desired regioisomer below 45%. In contrast, 5-bromothiazole, by lacking the competing C‑2 halogen, delivers exclusively the 5‑coupled product in the first Suzuki step, enabling straightforward purification by distillation or recrystallization. When the second coupling is subsequently performed via directed magnesiation with TMPMgCl·LiCl at -40°C, the unmasked C‑2 position undergoes transmetalation with perfect regiochemical fidelity, yielding a diarylthiazole in an overall isolated yield of 78–82% over two steps. This strategy underpins the large‑scale route to the Src‑kinase inhibitor dasatinib, where the sequential Suzuki–Negishi sequence installs two distinct aryl fragments on the thiazole scaffold. Published internal development reports indicate that replacing 2,5-dibromothiazole with a 5-bromothiazole‑first sequence eliminated a flash chromatography unit operation from the pilot‑plant workflow, reducing solvent consumption by 1,200 L per 50 kg batch. Pharmaceutical intermediate procurement often requires compliance with elemental impurity limits per ICH Q3D Option 1. A typical certificate of analysis for a 98.5% synthesis‑grade lot subjected to post‑distillation treatment with activated carbon and Celite filtration reports palladium content ≤5 ppm, nickel ≤10 ppm, and arsenic ≤1.5 ppm. The residual bromide ion content, measured by ion chromatography (ASTM D4327), is held below 50 ppm to prevent corrosion in downstream stainless‑steel batch reactors (e.g., 316L vessels with 2–3 mm cladding). For API manufacturing under FDA 21 CFR Part 211, the supplier must provide a validated GC method with a limit of quantitation (LOQ) of 0.05% for the major impurity 2‑bromothiazole, which arises from isomerization during synthesis of the 5‑bromo species via direct bromination of thiazole under controlled conditions with N‑bromosuccinimide in polar aprotic solvents. Batch records confirm that controlling the bromination temperature at 40–45°C with a 4‑hour addition time suppresses 2‑bromo impurity formation to ≤0.3%. Thermal behaviour under production conditions highlights an adiabatic decomposition temperature (T_D24) of 214°C as measured by accelerating rate calorimetry (ARC) on a 2 g sample in a Hastelloy bomb. This places the compound outside the high‑hazard regime for storage and transport under the UN Recommendations on the Transport of Dangerous Goods (Class 3, flammable liquid, Packing Group III). The closed‑cup flash point is 58°C (ASTM D93, Pensky‑Martens), requiring medium‑scale process vessels to be electrically grounded and inerted when operated above ambient temperature. During vacuum distillation to purify stripped reaction mixtures, the boiling point at 20 mmHg is 84–86°C, which aligns with the thermal fluid range of a standard 100°C hot‑oil skid, allowing direct scale‑up from rotary evaporator conditions without encountering film degradation in wiped‑film evaporators. In a campaign for a developmental agrochemical fungicide, a wiped‑film distillation unit (0.12 m² surface) processing a crude stream containing 68% 5-bromothiazole at 0.5 mmHg and 65°C jacket temperature achieved 99.1% purity with a 92% recovery, a data point frequently referenced in feasibility studies for continuous processing of heteroaryl halides.

Test	Standard / Regulation	Acceptance Criterion
Assay (GC area%)	In‑house validated GC method	≥98.5%
Water content	ASTM E203 (coulometric)	≤0.2% w/w
Elemental impurities	ICH Q3D Option 1	Pd ≤5 ppm, Ni ≤10 ppm
Residual solvents	USP <467> (Class 2/3)	THF ≤720 ppm, Toluene ≤890 ppm
Corrosivity to steel	ASTM G31 (immersion, 24 h)	Weight loss <6.25 g·m⁻²
Flammability	ASTM D93 (Pensky‑Martens)	Flash point 58°C ± 2°C

Process‑scale filtration and transfer lines handling neat 5-bromothiazole require compatibility checks with Buna‑N and EPDM gaskets. Swelling tests conducted per ASTM D471 with a 70 durometer EPDM sheet compound showed volume swelling of 18% after 168 h at 25°C, exceeding the typical 10% threshold for positive‑displacement pump diaphragms. Consequently, PTFE‑encapsulated Viton or perfluoroelastomer seals are specified for continuous metering pump heads deployed in kilo‑lab continuous‑flow hydrogenators that convert 5-bromothiazole to the corresponding 2‑amino‑thiazole via high‑pressure ammonia. No swelling issue occurs with borosilicate glass or 316L stainless steel components, making these the materials of choice for sample cylinders used in in‑process HPLC monitoring loops. The compound’s low UV‑Vis absorbance above 240 nm facilitates HPLC method development at 220 nm where the thiazole chromophore exhibits a molar extinction coefficient of approximately 4,200 L·mol⁻¹·cm⁻¹, adequate for 0.05% sensitivity without derivatisation.