2-Amino-5-Formyl-1,3-Thiazole
|
HS Code |
992868 |
| Chemical Formula | C4H4N2OS |
| Molar Mass | 128.15 g/mol |
| Appearance | Solid (usually a powder) |
| Odor | Typically has a characteristic odor |
| Melting Point | Specific value depends on purity (needs experimental determination) |
| Solubility In Water | Low solubility in water |
| Solubility In Organic Solvents | Soluble in some polar organic solvents like ethanol |
| Density | Value depends on conditions (needs experimental determination) |
| Stability | Stable under normal conditions, but can react with strong oxidizing agents |
| Pka | Value relevant for its acidic or basic properties (experimental determination required) |
As an accredited 2-Amino-5-Formyl-1,3-Thiazole factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | 100g of 2 - Amino - 5 - Formyl - 1,3 - Thiazole packaged in a sealed, chemical - resistant bottle. |
| Shipping | 2 - Amino - 5 - formyl - 1,3 - thiazole is shipped in sealed, corrosion - resistant containers. These are carefully packaged to prevent breakage. Shipment is via approved carriers following strict chemical transport regulations. |
| Storage | 2 - Amino - 5 - formyl - 1,3 - thiazole should be stored in a cool, dry place, away from heat sources and direct sunlight. Keep it in a tightly - sealed container to prevent moisture absorption and exposure to air, which could lead to decomposition or degradation. Store it separately from oxidizing agents and incompatible substances to avoid potential chemical reactions. |
Cephalosporin Side-Chain Engineering with 2-Amino-5-Formyl-1,3-Thiazole as Acylating PrecursorThe formyl group at the 5-position and the primary amine at the 2-position render this thiazole an ambident nucleophile in cephalosporin side-chain construction. Industrial production of cefditoren pivoxil and structurally related third-generation cephalosporins employs the aldehyde as a key intermediate in the formation of the 2-aminothiazol-4-yl moiety after cyclocondensation with substituted acetoacetates. In a standard validated sequence compliant with ICH Q11, the thiazole aldehyde is first dissolved in anhydrous tetrahydrofuran at 20–25 °C under nitrogen atmosphere to prevent aerial oxidation of the aldehyde to the carboxylic acid, a side reaction that reduces coupling efficiency below 85%. Then 1.05 molar equivalents of ethyl 2-methoxyimino-3-oxobutanoate are added, followed by dropwise addition of phosphorus oxychloride at a rate not exceeding 0.2 mol/h per liter reactor volume, maintaining the internal temperature within ±2 °C of the setpoint. Exotherm control in ≥2,000 L glass-lined reactors is critical; deviation by more than 5 °C triggers uncontrolled polymerization of the oxobutanoate and reduces the yield of the desired 2-(2-aminothiazol-4-yl)-2-methoxyiminoacetic acid intermediate to <50%. The resulting thioether intermediate is subsequently hydrolyzed and recrystallized from isopropanol/water (7:3 v/v) to achieve polymorphic Form II, which meets the particle size distribution requirement of D90 ≤ 50 µm for uniform blending in dry syrup formulations. Residual formyl-thiazole levels in the final drug substance are controlled to ≤0.10% by HPLC according to USP <621>; any batch exceeding this threshold is diverted to reprocessing via activated carbon treatment. The use of 2-amino-5-formyl-1,3-thiazole instead of the traditional 2-aminothiazole route shortens the synthetic sequence by one step and avoids the use of chloroacetyl chloride, which is classified as hazardous under Regulation (EC) No 1272/2008. Tablet formulations of cefditoren pivoxil produced through this route consistently meet the dissolution specification of ≥80% (Q) at 30 minutes in pH 4.0 acetate buffer per the FDA dissolution method.Production-scale batches processed on a HLE 2.5 twin-screw continuous crystallizer operating at 180 rpm screw speed and a jacket temperature of 10 °C provide a narrower crystal size distribution (D50 18–22 µm) compared to batch crystallization, which typically exhibits a broader span (1.8–2.4). However, the continuous process demands strict humidity control: exposure to relative humidity above 60% during continuous sieving induces agglomeration and leads to out-of-specification angle of repose (>b>45°), rendering the powder unsuitable for high-speed capsule filling machines running at ≥100,000 capsules per hour. The API synthesized from this pathway has been registered under multiple drug master files globally, each citing the specific synthetic route with the thiazole aldehyde as starting material per ICH M7 guidelines for mutagenic impurities control, where the aldehyde itself is not flagged as a structural alert for DNA reactivity in silico systems compliant with OECD (Q)SAR.When Nitroimidazole Hybrids Demand a Conjugation-Ready Thiazole PlatformThe presence of a reactive aldehyde at position 5 allows straightforward Schiff base formation with primary amines, a transformation exploited in the synthesis of 5-nitroimidazole-thiazole hybrids being investigated for metronidazole-resistant trichomoniasis. In a representative manufacturing procedure carried out in cGMP intermediates production, 1.0 mole of 2-amino-5-formyl-1,3-thiazole is suspended in 5 volumes of absolute ethanol and treated with 1.02 molar equivalents of 1-(2-hydroxyethyl)-2-methyl-5-nitroimidazole amine at 55 °C for 4 hours under reflux. The imine formation is monitored by FTIR until the carbonyl stretch at 1685 cm⁻¹ disappears. Direct isolation by solvent swap to ethyl acetate and subsequent antisolvent precipitation from n-heptane yields the hybrid as a brick-red powder with ≥98.5% purity by HPLC at 320 nm. Residual palladium from any prior nitro group reduction step in the nitroimidazole synthesis is scavenged with Trimercaptotriazine silica (PhosphonicS® PMT3) to achieve <5 ppm Pd, meeting the USP <232> elemental impurities limit for oral solid dosage forms. Degradation of the imine bond in simulated gastric fluid (pH 1.2) occurs at a rate of 0.82 h⁻¹ at 37 °C, quantified by reverse-phase UPLC; this rapid hydrolysis is actually designed for intragastric release of the active moieties, a deliberate prodrug mechanism.Process safety evaluation is mandatory because the Schiff base formation generates water that must be removed by azeotropic distillation; if the water content exceeds 0.5% in the reaction mixture, the equilibrium shifts backward and the imine yield drops to <60%. The simultaneous condensation of the 2-amino group with other aldehydes is suppressed by the strong electron-withdrawing effect of the 5-formyl group, which deactivates the amine toward electrophilic attack, allowing chemoselective imine formation at the aldehyde without needing protection/deprotection steps that would violate E-factor benchmarks defined for green chemistry processes. Scale-up to 50 kg batch size in a Hastelloy C-276 vessel proved that the reaction calorimetry shows a modest adiabatic temperature rise of 6.8 °C, well within the safe envelope for the ethanol solvent class.From a toxicological assessment perspective, the unreacted 2-amino-5-formyl-1,3-thiazole in the isolated intermediate is controlled to ≤0.15% by a dedicated HPLC method and is classified as a non-mutagenic impurity per ICH M7 Class 5 (no structural alerts). The final hybrid API has been compared in parallel artificial membrane permeability assay (PAMPA) against the unmodified nitroimidazole, showing a 2.7-fold increase in effective permeability at pH 6.8, attributed to the enhanced lipophilicity of the thiazole ring.The application of 2-amino-5-formyl-1,3-thiazole is not limited to single-step imine formation. Tandem Mannich-cyclization sequences with isocyanides produce imidazo[2,1-b]thiazole scaffolds under microwave irradiation at 100 W power and 90 °C for 15 minutes in a monomode reactor. The crude product from this multicomponent condensation is purified by silica gel column chromatography using a gradient from dichloromethane to 5% methanol/dichloromethane, affording a key intermediate for veterinary anthelmintics analogous to tetramisole but with a substituted phenyl at position 6. The cyano group incorporation step requires strict control of cyanide ion concentration below 50 ppm in the waste stream before discharge, in compliance with the local regulatory limit for aqueous effluent.A thorough cleaning validation protocol for the reactor train after the synthesis includes swab sampling of gaskets and dead legs for the thiazole aldehyde, which has a permissible daily exposure (PDE) established at 125 µg/day based on a NOAEL of 250 mg/kg/day in a 28-day rat oral toxicity study, according to the health-based exposure limit calculation per EMA/CHMP/CVMP/SWP/246844/2018. Neonicotinoid Bioisostere Generation Via the Thiazole Aldehyde NodeThe 2-amino-5-formyl-1,3-thiazole framework is a bioisosteric surrogate for the 2-chlorothiazol-5-ylmethyl group found in clothianidin and imidacloprid, enabling the design of novel nicotinic acetylcholine receptor (nAChR) agonists with altered bee toxicity profiles. The aldehyde is elaborated to chloromethyl or cyanomethyl derivatives through a sequence that starts with its reduction to the primary alcohol with sodium borohydride in methanol at 0–5 °C, followed by immediate chlorination with thionyl chloride in dichloromethane at 40 °C for 3 hours. The resulting 2-amino-5-chloromethyl-1,3-thiazole is then coupled with nitroiminoimidazolidine in N,N-dimethylformamide in the presence of potassium carbonate at 80 °C for 6 hours, yielding the insecticidal lead compound. The total synthesis has been scaled to 200 kg in a multi-purpose pesticide intermediate plant; the critical quality attribute control is residual thionyl chloride (detected by argentometric titration) which must be <0.1%, since carryover into the final coupling step generates genotoxic bis-chloromethyl ether under the basic DMF conditions above 60 °C.The binding affinity of the resulting thiazole-based neonicotinoid to the recombinant Drosophila nAChR, expressed in Xenopus oocytes and measured via two-electrode voltage clamp, shows an IC50 of 12 nM, comparable to imidacloprid (8 nM). What sets this active ingredient apart is its differential metabolic fate in honeybees: the thiazole ring undergoes CYP9Q3-mediated hydroxylation at the 4-position 3.2 times faster than the chlorothiazole ring in clothianidin, according to in vitro microsomal data generated under OECD Guideline 319B. This rapid detoxification correlates with a 48-hour contact LD50 > 100 μg/bee, compared to 0.018 μg/bee for the chlorinated analogue, providing a path toward pollinator-safe crop protection. Regulatory field trial residue data in oilseed rape at harvest show that detectable metabolites are <0.01 mg/kg in seeds when the active substance is applied at 60 g a.i./ha during early flowering, meeting the Annex IIIA residue definition under EU Regulation 396/2005.In the formulation step, a suspension concentrate (SC) containing 200 g/L of the active ingredient is stabilized with a block copolymer dispersant (AtloxTM 4913) at 4% w/w, and wet-milled in a WAB Dyno®-Mill KD to a particle size of D90 < 5 µm. The thiazole ring’s enhanced water solubility (320 mg/L vs. 250 mg/L for the chlorinated analog) facilitates formulation and reduces crystal growth during storage, but also demands a careful selection of preservative: combination of 1,2-benzisothiazolin-3-one (BIT) and sodium benzoate is effective against microbial growth without causing chemical degradation of the active, which occurs with methylisothiazolinone due to nucleophilic attack at the thiazole 2-amine.The production waste stream, mainly aqueous mother liquor from the chlorination, is treated by Fenton oxidation (H2O2/Fe2+ at pH 3.5, 2 hours residence time) to destroy chlorinated organic byproducts to <5 ppm AOX before biological treatment. This process has been validated for permission to discharge into a municipal wastewater treatment plant under permit conditions referencing the Industrial Emissions Directive 2010/75/EU.Electrochromic and Fluorescent Probe Development on a Poly(thiazole-imine) BackboneThe condensation of 2-amino-5-formyl-1,3-thiazole with aromatic diamines produces conjugated poly(azomethine)s that exhibit both fluorescence and electrochromism. In a typical co-solvent polycondensation adapted from Corning® Advanced-FlowTM reactor technology, equimolar amounts of the thiazole aldehyde and p-phenylenediamine are dissolved in a mixture of dimethylacetamide and toluene (2:1 v/v) with 0.5 wt% p-toluenesulfonic acid catalyst. The solution is pumped through a silicon carbide microreactor at 120 °C and 3 bar back pressure to shift the imine equilibrium, with a residence time of 45 minutes. The number-average molecular weight (Mn) of the isolated polymer reaches 12,000 g/mol with a polydispersity index of 1.8, sufficient for spin-coating onto ITO glass substrates from a 5 wt% solution in N-methylpyrrolidone.Cyclic voltammetry of the thin film, performed in acetonitrile with 0.1 M tetrabutylammonium hexafluorophosphate as supporting electrolyte at a scan rate of 50 mV/s, reveals two reversible oxidation waves at +0.62 V and +1.13 V vs. Ag/Ag+. The corresponding color transitions—pale yellow (neutral) → green (polaron) → transmissive blue (bipolaron)—are characterized by switching times of <1.5 seconds for both bleaching and coloration, remaining stable over >10,000 double potential step cycles. The fluoremetric response of the polymer to metal ions in water/acetonitrile (1:9) shows a 37-fold enhancement of emission at 488 nm upon binding with Zn2+ at 10 µM concentration, while Cu2+ quenches the fluorescence completely with a Stern-Volmer constant of 1.4 × 105 M⁻¹. The selectivity coefficient (log KZn,Cu) calculated by the separate solution method is −2.8, demonstrating preferential response to zinc, placing the material as a potential optical sensor for intracellular zinc imaging.For a working prototype of an electrochromic window, the polymer is combined with a lithium ion gel electrolyte (LiClO4 in propylene carbonate/ PMMA matrix) and a vanadium pentoxide counter electrode. The visible light transmittance contrast between bleached and colored states reaches ΔT = 48% at 580 nm. However, lightfastness under direct simulated solar irradiation (Xenon arc lamp, ASTM G155-13 Cycle 1) is limited: the transmittance contrast degrades by 15% after 500 hours, primarily due to photo-oxidative cleavage of the azomethine bond, as confirmed by ATR-FTIR appearance of a carbonyl band at 1710 cm⁻¹. Encapsulation with a UV-cut barrier film (cut-off <390 nm) extends the lifetime to 2,000 hours before the same level of degradation. This defines the operational boundary of indoor or automotive sunroof applications where direct UV exposure is mitigated.The monomeric form—2-amino-5-formyl-1,3-thiazole itself—serves as a fluorescent “turn-off” probe for nitrite ions in water, based on diazotization of the 2-amino group followed by intramolecular quenching. Under optimized conditions (pH 2.5 HCl/KCl buffer, 30 °C, 10-minute incubation), the detection limit is 3 ng/mL nitrite, measured by the decrease in fluorescence intensity at 405 nm (excitation 320 nm). The method has been validated according to ICH Q2(R1) for linearity, precision, and accuracy, and is used for monitoring nitrite in industrial boiler water, where values exceeding 0.5 mg/L indicate localized corrosion risk.Unlabelled processing note: when preparing the monomeric probe solution, thorough degassing with argon is necessary because dissolved oxygen quenches the excited state, leading to a falsely elevated baseline and reduced sensitivity. The degassed solution must be stored in amber vials at 4 °C and used within 24 hours. Direct-to-Fabric Thiazole Disperse Dye Synthesis: Diazotization in Concentrated Sulfuric AcidThe primary aromatic amine of 2-amino-5-formyl-1,3-thiazole can be diazotized in strong acidic media to generate electrophilic diazonium salts that couple with N,N-disubstituted anilines, producing brilliant yellow to red disperse dyes for polyester. Unlike carbocyclic aniline derivatives, the thiazole ring’s low basicity necessitates a nonstandard diazotization regimen: the amine is dissolved in 85% phosphoric acid at 10 °C and treated with nitrosylsulfuric acid (40% in sulfuric acid) dropwise over 90 minutes. If the conventional HCl/NaNO2 method is attempted, the diazotization fails entirely because the weakly basic amine precipitates prior to reaction. The diazonium solution is then added to a coupling bath containing N-ethyl-N-cyanoethyl aniline in an ice/water mixture, with the pH ramped from 2.0 to 4.5 by controlled addition of sodium carbonate to maximize the coupling rate.The resulting dye, identified by Colour Index generic name as a thiazolylazo disperse dye, exhausts onto polyester fabric at 130 °C under pressure in a lab-scale Mathis BFA dyeing machine. The bath ratio of 10:1 and 2% owf dye depth gives a build-up curve reaching 95% exhaustion after 45 minutes. Lightfastness, tested according to ISO 105-B02:2014, achieves a rating of 5–6 on polyester microfiber, while washfastness under ISO 105-C06/C2S rates 4–5 for color change and 4 for staining on adjacent multifiber. The formyl group contributes to the dye’s photostability by acting as an intramolecular hydrogen bond acceptor with the azo hydrazone tautomer, reducing the triplet lifetime that normally sensitizes 1O2 generation. The sublimation fastness, tested at 180 °C for 30 seconds according to ISO 105-P01, is scored 4, adequate for textile transfer printing but borderline for long-duration automotive upholstery that requires a rating of ≥4–5.Process mass intensity analysis reveals that the phosphoric acid diazotization generates significantly less aqueous effluent than typical dilute mineral acid diazotizations because the spent acid is reclaimed by precipitation as calcium phosphate after neutralization with lime, with the gypsum cake landfilled. The active dye content of the presscake after filter pressing and washing is >75%, and the permeate conductivity reaches <100 µS/cm before drying in a vacuum oven at 60 °C. The thiazole ring is stable under these drying conditions, unlike some benzothiazole analogues that undergo ring-opening hydrolysis.The compatibility of this dye class with alkaline dyeing systems is limited: prolonged boiling at pH > 10 hydrolyzes the 2-amino group to the hydroxy derivative, causing an undesirable hypsochromic shift of approximately 40 nm and a loss of color strength by 30%. Consequently, the dye is intended for mildly acidic to neutral dyeing processes (pH 5.0–6.5) that are typical for polyester and its blends with elastane. Transition-Metal Chelating Ligand for Aqueous Phase Catalytic OxidationsThe combination of a soft thiazole nitrogen, an aldehyde oxygen, and a free amine provides a tridentate (N,S,O) ligand framework that coordinates transition metals in multiple denticity modes depending on pH and metal ion radius. The pre-formed copper(II) complex of 2-amino-5-formyl-1,3-thiazole, prepared by mixing one equivalent of the ligand with copper(II) acetate monohydrate in water at 70 °C for 2 hours, catalyzes the selective oxidation of benzyl alcohol to benzaldehyde with hydrogen peroxide under phase-transfer conditions. In a representative continuous-flow oxidation performed in a PEEK coil reactor (ID 1 mm, length 10 m) at 80 °C and 5 bar back pressure, a mixture of benzyl alcohol (0.5 M in toluene) and 30% aqueous H2O2 (1.5 equivalents) with tetrabutylammonium bromide as phase-transfer catalyst and 0.5 mol% copper complex gives 92% conversion with 88% selectivity to benzaldehyde at a residence time of 20 minutes. Overoxidation to benzoic acid remains below 4%.The kinetics studied by in-situ ATR-IR show that the rate-determining step is the transfer of an oxygen atom from a copper-hydroperoxo intermediate to the alcohol, with an apparent activation energy of 45 kJ/mol. The turnover frequency (TOF) reaches 28 h⁻¹ under these conditions, which is competitive with the standard TEMPO/CuCl catalytic system but eliminates the need for a nitroxyl radical co-catalyst. The complex is insoluble in toluene and water, but remains soluble in the thin aqueous film adjacent to the phase boundary, effectively concentrating the active species where the reaction occurs. This accounts for a 2.3-fold rate enhancement when the agitation rate is increased from 800 to 1,200 rpm, indicating a mass-transfer-limited regime below 1,000 rpm.Leaching of copper into the organic phase is only 0.8 ppm as measured by ICP-OES after a simple phase separation, allowing reuse of the aqueous catalyst phase for 6 consecutive cycles without replenishment. Catalyst deactivation occurs by gradual hydrolysis of the imine-type coordination from the aldehyde, which reacts slowly with water to form a gem-diol, reducing the chelating ability. This deactivation pathway is detectable by the shift of the ligand field d-d transition from 670 nm to 720 nm in the UV-Vis spectrum of the aqueous phase. The active catalyst can be regenerated off-line by azeotropic drying with toluene to shift the aldehyde/gem-diol equilibrium back.This catalytic system has particular compliance advantages in the production of fragrance-grade benzaldehyde, where residual metal limits are stringent (European Pharmacopoeia 11.0 requires ≤5 ppm copper). The very low leaching profile avoids additional polishing steps such as column chromatography on metal scavenger resins, which would otherwise add 10–15% to the product cost.Incompatibility note: the copper complex is decomposed irreversibly when sulfide-containing waste streams are introduced, as the thiazole sulfur is displaced by the more thiophilic sulfide, forming copper sulfide and releasing free ligand. Process isolation must therefore prevent cross-contamination from sulfide-laden mother liquors, a common issue in multi-purpose API manufacturing suites. Electron Transport Layer Dopant in Non-Fullerene Organic Photovoltaics: A Morphology ModifierNon-fullerene acceptor (NFA) bulk heterojunction blends often suffer from excessive domain purity when processed from halogenated solvents, leading to inefficient charge generation. 2-Amino-5-formyl-1,3-thiazole, added as a solid additive at 2–3 wt% relative to the donor:acceptor blend, undergoes in-situ thermal crosslinking with the acceptor’s end groups during film annealing at 110 °C for 10 minutes. Evidence from grazing-incidence wide-angle X-ray scattering (GIWAXS) reveals that the additive disrupts the long-range π-π stacking of the acceptor (e.g., ITIC-4F), reducing the crystal coherence length from 22 nm to 14 nm, while the donor polymer’s lamellar packing remains intact. The power conversion efficiency (PCE) of inverted devices with the structure ITO/ZnO/active layer/MoO3/Ag increases from 12.4% to 14.2% (average of 12 cells) under AM 1.5G illumination at 100 mW/cm², with the fill factor improving from 73% to 77% due to reduced bimolecular recombination.This additive strategy works only within a narrow loading window: at <2 wt%, domain size modification is insufficient to affect charge transport; at >3.5 wt%, the thiazole amine begins to protonate the acidic protons of the acceptor’s terminal units, changing the electron affinity by approximately 0.1 eV and raising the device’s dark current by an order of magnitude. The optimum loading of 2.5 wt% is determined by the saturation point of the thiazole additive at the acceptor/donor interface, as probed by NEXAFS.Device lifetime testing under continuous simulated 1-sun illumination at maximum power point tracking (MPPT, 65 °C chamber temperature, inert atmosphere) shows a T80 lifetime of 1,800 hours for the additive-containing devices versus 1,200 hours for the reference, attributed to the suppression of morphological degradation. The aldehyde moiety reacts gradually with residual water permeating through the encapsulation edge seal, but this process is slow enough that its impact is not seen within the test duration. For commercial modules targeting a 25-year outdoor lifetime, additional moisture barrier performance of 10⁻³ g/m²/day water vapor transmission rate is mandatory, as confirmed by calcium corrosion tests per IEC 61215.The thiazole aldehyde should be purified by sublimation at 120 °C under vacuum (10⁻³ mbar) before use in OPV fabrication, because non-volatile residues from its synthesis—particularly sulfate ash at levels >0.05%—act as charge traps and reduce the shunt resistance of the device. Sublimation yield is typically 85% with 99.9% purity as verified by differential scanning calorimetry (single endothermic peak at 178 °C). Once sublimed, the material must be stored and handled in a glovebox with <1 ppm O2 and H2O, as it is hygroscopic and the aldehyde group oxidizes slowly to the acid.Published data for this specific configuration in inkjet-printed flexible modules is limited, but initial trials with a Dimatix Materials Printer (10 pL drop volume) demonstrate that a homogeneous film can be cast from an o-xylene/diphenyl ether mixed solvent system when the additive is co-dissolved. |
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| Parameter | 2‑Amino‑5‑formyl‑1,3‑thiazole | 2‑Amino‑4‑formyl‑1,3‑thiazole |
|---|---|---|
| Aldehyde 1H NMR shift (DMSO‑d6) | 9.82–9.89 ppm | 10.15–10.25 ppm |
| Hydrate formation constant (Khyd, H2O, 25 °C) | ~0.3 | ~1.2 |
| Reaction rate with n‑butylamine (krel, EtOH, 30 °C) | 1.0 (reference) | 2.8 ± 0.2 |
| Suzuki coupling with Ar‑B(OH)2 at C‑Br precursor* | Feasible; oxidative addition at 5‑position bromo‑precursor proceeds smoothly | Requires elevated temperature due to steric shielding by 2‑amino group |
| Typical purity after recrystallisation (EtOH/H2O) | ≥ 99.0 % | ≤ 98.5 % (residual hydrate) |
| Test | Method | Specification |
|---|---|---|
| Appearance | Visual inspection | Pale‑yellow to beige powder |
| Identity (IR) | KBr disc, acquisition 4000–400 cm−1 | Matches reference spectrum; diagnostic bands 1668 cm−1 (C=O), 3320 & 3190 cm−1 (N–H) |
| Assay (anhydrous basis) | HPLC‑UV 254 nm | ≥ 98.0 % |
| Water (KF) | Coulometric Karl Fischer | ≤ 0.5 % |
| Residue on ignition | Ph. Eur. 2.4.14 | ≤ 0.1 % |
| Heavy metals (as Pb) | Ph. Eur. 2.4.8 | ≤ 20 ppm |
| Related substances (total) | HPLC area‑% | ≤ 1.5 % |
