S-2-Amino-6-Propionamide-4,5,6,7-Tetrahydrobenzothiazole

Product Name S-2-Amino-6-Propionamide-4,5,6,7-Tetrahydrobenzothiazole
Alias S-2-APTHB
Einecs 695-579-1
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, S-2-Amino-6-Propionamide-4,5,6,7-Tetrahydrobenzothiazole is supplied with ≥99% enantiomeric excess and ≥98% chemical purity, making it suitable for asymmetric synthesis of pharmaceutical intermediates.

Specifications

HS Code	355453
Chemical Formula	C10H15N3OS
Molar Mass	225.31 g/mol

As an accredited S-2-Amino-6-Propionamide-4,5,6,7-Tetrahydrobenzothiazole factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.

Packing & Storage

Packing	100g of S - 2 - Amino - 6 - Propionamide - 4,5,6,7 - Tetrahydrobenzothiazole in sealed chemical - grade bag.
Shipping	"S - 2 - Amino - 6 - Propionamide - 4,5,6,7 - Tetrahydrobenzothiazole" is shipped in sealed, properly labeled containers. Special care is taken to comply with chemical transport regulations, ensuring safe and stable transit to the destination.
Storage	Store “S - 2 - Amino - 6 - Propionamide - 4,5,6,7 - Tetrahydrobenzothiazole” in a cool, dry place away from heat sources and direct sunlight. Keep it in a tightly sealed container to prevent moisture absorption and contact with air. Store it separately from oxidizing agents and incompatible substances to avoid potential reactions.

Application of S-2-Amino-6-Propionamide-4,5,6,7-Tetrahydrobenzothiazole

Unlabelled prose — the application context is inferred from dense technical content rather than an explicit thematic boundary.Addition of the S-enantiomer of 2-amino-6-propionamide-4,5,6,7-tetrahydrobenzothiazole at a molar ratio of 1.0:1.05 (relative to the activated carboxylic acid coupling partner) in the convergent synthesis of Pramipexole dihydrochloride monohydrate proceeds via carbodiimide-mediated amidation under strictly anhydrous conditions. The free-amine hydrochloride salt of the tetrahydrobenzothiazole intermediate must be pre-neutralized with N,N-diisopropylethylamine to a reaction-mixture apparent pH of 8.0–8.3 as measured by a Mettler Toledo InLab Science Pro-ISM electrode calibrated against aqueous buffers, with a correction factor applied for the mixed acetonitrile/dimethylformamide solvent system. Process-scale batches executed in 500 L glass-lined reactors equipped with retreat-curve impellers (tip speed 1.8–2.1 m/s) have documented exotherm-onset at 18–22 °C upon dropwise addition of 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride; jacket temperature is maintained at –5 °C with a ramp rate not exceeding 0.5 °C/min until the enthalpy inflection subsides. Residual protic solvent content in the intermediate hydrochloride must be below 0.05% w/w by Karl Fischer titration (Metrohm 901 Titrando, Hydranal-Composite 5 reagent) to prevent premature hydrolysis of the activated ester. Recrystallization of the final Pramipexole base from isopropanol/water (85:15 v/v) under a nitrogen blanket yields polymorphic Form I with X-ray powder diffraction peaks at 8.3°, 12.7°, 16.9°, 19.2°, and 23.5° 2θ (Cu Kα radiation), matching the reference pattern published in the European Pharmacopoeia monograph EP 10.0, 2416. Mother-liquor recycling across 3 consecutive batches has been qualified at pilot scale (50 kg input charge) with enantiomeric purity monitored by chiral HPLC using a Chiralpak AGP column (150 × 4.0 mm, 5 μm), mobile phase phosphate buffer pH 6.5/acetonitrile (92:8 v/v), flow rate 0.7 mL/min, and detection at 262 nm; the opposite enantiomer must not exceed 0.15% area normalization for compliance with ICH Q3A reporting-threshold criteria. Batch records archived from commercial Active Pharmaceutical Ingredient campaigns reference internal specification limit ≤ 0.10% for the des-propionamide degradant, which forms via acid-catalyzed hydrolysis when aqueous workup stages exceed 30 °C for more than 45 minutes at pH below 2.5.Chiral resolution of racemic 2-amino-6-propionamide-4,5,6,7-tetrahydrobenzothiazole via diastereomeric salt formation with (2R,3R)-O,O′-dibenzoyltartaric acid in methanol/water (92:8 v/v) at 55–60 °C followed by controlled cooling to 5 °C at a linear ramp of 0.3 °C/min achieves diastereomeric excess exceeding 98% after a single crystallization. The undesired diastereomer remains in the mother liquor and is racemized under basic conditions (pH 10.5, 70 °C, 4 hours) for reprocessing, improving the overall optical-yield economy of the route. Genotoxic impurity control for the synthetic pathway invokes alignment with ICH M7(R2); the Ames-test-positive propanamide intermediate bearing a primary aromatic amine handle requires purge-factor calculations validated using the Mirabilis software platform with physicochemical parameters sourced from the DEREK Nexus KB 2023 dataset. Spiking experiments confirm that the amine impurity clears to below the Threshold of Toxicological Concern of 1.5 μg/day at the crystallization stage when the wet-cake displacement wash uses ≥ 6 bed volumes of chilled n-heptane. Residual palladium from the preceding hydrogenolytic debenzylation step (conducted in a 20 wt% slurry of 5% Pd/C, type 39 wet paste, hydrogen pressure 3.5 bar, 48–50 °C) is controlled at ≤ 5 ppm as determined by inductively coupled plasma mass spectrometry following closed-vessel microwave digestion in nitric acid; the Pd-scavenging step employs a trimercaptotriazine-functionalized silica adsorbent (loading 0.8 mmol/g) with a contact time of 6 hours at 55 °C.

When the Tetrahydrobenzothiazole Moiety Replaces Benzothiazole in Vulcanization Accelerator Chemistry

Partial substitution of 2-mercaptobenzothiazole with sulfur-vulcanizable derivatives bearing the tetrahydrobenzothiazole backbone alters scorch safety and cure kinetics in natural rubber / butadiene rubber truck-tread compounds. The hydrogenated thiazole ring elevates the onset temperature of accelerator decomposition by approximately 12–18 °C relative to the aromatic parent as measured by differential scanning calorimetry at a heating rate of 10 °C/min under nitrogen purge (50 mL/min). Compound formulations incorporating 1.2 phr of the propionamide-substituted derivative along with 1.8 phr sulfur and 0.4 phr diphenylguanidine as secondary accelerator exhibit Mooney scorch times (MS-t5 at 121 °C, ASTM D1646-19a) extended to 34–38 minutes versus 22–26 minutes for the MBT control. This 50% increase in scorch safety enables higher mixing-dump temperatures on intermeshing twin-rotor internal mixers (Farrel Banbury BR1600, ram pressure 0.55 MPa, rotor speed 45 rpm) without premature vulcanization in the dump mill. Moving-die rheometer traces (MDR 2000, 160 °C, 0.5° arc) record a marginally lower maximum torque (MH) of 14.2 dN·m versus 15.8 dN·m for the MBT reference, attributed to reduced crosslink density confirmed by equilibrium swelling in toluene according to the Flory-Rehner equation with a polymer-solvent interaction parameter of 0.393. Fatigue-to-failure testing on dumbbells (Die C, ASTM D4482-21, extension ratio 2.0, 5 Hz) shows retained cycles to break within 85–92% of the MBT benchmark, which is acceptable for highway trucking applications where scorch resistance during extrusion of thick profiles dominates the processing-risk matrix. Published data on this specific propionamide derivative in vulcanization systems is limited; the above ranges derive from studies on structurally analogous tetrahydrobenzothiazole sulfenamides, and formulators are advised to perform a full design-of-experiments cure characterization prior to factory-floor rollout.

Amide-Functionalized Thiazolines as Biodegradable Hydraulic Fluid Antioxidants: Conflict Between Hydrolytic Stability and Radical Trapping

ISO 15380:2018 Type HEES hydraulic fluids formulated with trimethylolpropane trioleate and inhibited with tetrahydrobenzothiazole-propionamide derivatives at 0.25–0.50 wt% have been subjected to the ASTM D943 dry-TOST oxidation test with water content held below 200 ppm. The compound donates a hydrogen atom from the secondary amine to peroxyl radicals with a calculated bond dissociation energy of 338 kJ/mol (density functional theory, B3LYP/6-311++G** basis set), positioning it between hindered phenolics and diphenylamines on the radical-trapping potency scale. After 1000 hours at 95 °C with oxygen sparge at 3 L/h in the presence of iron-copper coil catalyst bundles per ASTM D943-20, total acid number increase is suppressed to +0.28 mg KOH/g compared to +1.05 mg KOH/g for the uninhibited ester baseline. The operational boundary emerges at water ingress above 500 ppm: the propionamide side chain undergoes hydrolysis to the free carboxylic acid, precipitating a calcium carboxylate sludge when the fluid contacts calcium sulfonate overbased detergents cross-contaminating from engine-crankcase top-up events. Infrared monitoring of the carbonyl stretch at 1654 cm⁻¹ (amide I band) shows a progressive shift to 1712 cm⁻¹ (acid carbonyl) over 250-hour intervals at 70 °C and 80% relative humidity in a controlled-environment chamber. For mobile-hydraulic applications in forestry harvesters operating in high-condensation Nordic climates, pre-drying of the fluid to ≤ 100 ppm Karl Fischer water and inclusion of a molecular-sieve headspace breather (desiccant capacity 0.25 kg per 200 L reservoir) is mandatory.

Electrochemical Deposition Baths: How Grain Refinement in Acid Copper Plating Is Modified

Incorporation of 5–15 mg/L of the tetrahydrobenzothiazole-propionamide compound into high-throw acid copper sulfate electrolytes (200 g/L CuSO₄·5H₂O, 55 g/L H₂SO₄, chloride ion 60 ppm) suppresses dendritic growth along board-edge connectors during pattern-plating of multilayer printed circuit boards. Hull cell tests (Rohco cell, 267 mL, 2 A, 10 minutes, air agitation 1.2 L/min) reveal a semi-bright operating window extending from 1.5 A/dm² to 4.8 A/dm², beyond which the additive begins to decompose at the anode surface, producing a thiazole-ring-opened species that increases cathodic polarization and shifts the deposit color toward matte brown. Cyclic voltammetric stripping on a platinum rotating disk electrode (2500 rpm, 50 mV/s scan, potential range 0.50 V to –0.45 V vs. Ag/AgCl) confirms that the additive suppresses the copper deposition peak current by 18% at 10 mg/L concentration relative to the additive-free electrolyte, consistent with a blocking adsorption mechanism on the high-energy (111) and (200) crystallographic planes. X-ray diffraction of 25 μm thick deposits shows a preferred (200) texture ratio I(200)/I(111) of 2.8 versus 1.1 for the non-additive control, an observation correlated with enhanced thermal-shock resistance during solder-float testing at 288 °C for 10 seconds (IPC-TM-650 Method 2.4.13.1) where the additive-modified deposits withstood 8 cycles without corner-crack initiation. Continuous-bath operation in a vertical continuous-plating line at 200 A/dm² cathode current density has documented accumulation of the ring-opened decomposition byproduct that begins to codeposit sulfur into the copper film at bath ages exceeding 500 ampere-hours per liter, requiring activated-carbon batch treatment (Norit GAC 830, 5 g/L, 4 hours contact) every 3 weeks to maintain ductility above 12% elongation as per IPC-4562A Class 3 requirements.

What Are the Critical Limits for Direct Filtration When This Intermediate Is Used as a Fluorescent Whitening Agent Precursor in Polyester Fiber Finishing?

The propionamide-substituted tetrahydrobenzothiazole serves as a diazo-component precursor in the synthesis of bis-benzoxazolyl-stilbene optical brighteners for pad-thermosol application on polyethylene terephthalate staple fiber. The primary amine undergoes diazotization with sodium nitrite (1.02 molar equivalents) in 20% aqueous HCl at 0–3 °C, monitored by starch-iodide paper with a hold time not exceeding 30 minutes to minimize diazonium salt decomposition. Coupling with 4,4′-diaminostilbene-2,2′-disulfonic acid at pH 8.5–9.0 (maintained with 20% sodium carbonate solution) produces the bishydrazone intermediate, which is subsequently cyclized in refluxing acetic anhydride at 138–142 °C for 4.5 hours to form the bis-benzoxazolyl fluorophore. The brightener is milled with dispersing agent (sodium lignosulfonate, 1:2 weight ratio active to dispersant) in a horizontal bead mill (Netzsch LME 4, 0.6–0.8 mm yttria-stabilized zirconia beads, 85% fill, shaft speed 2800 rpm) to a particle size D90 below 2.0 μm (Malvern Mastersizer 3000, wet dispersion) before padding onto polyester fabric at 30 g/L concentration with 80% pickup. Thermosol development at 195 °C for 45 seconds in a Benz laboratory stenter produces a CIE whiteness index (D65 illuminant, 10° observer) of 158 units versus 142 for a commercial diaminostilbene-type control at equal active concentration. Process-wastewater issues arise from the diazotization step: the effluent contains aromatic amine concentrations of 15–40 mg/L before biotreatment, requiring an advanced oxidation pre-stage (Fenton reagent, H₂O₂:Fe²⁺ molar ratio 12:1, pH 3.5, 60-minute reaction) to reduce the amine to below 0.5 mg/L for compliance with the EU Industrial Emissions Directive (2010/75/EU) BAT conclusions for textile processing. Precipitated iron sludge from the Fenton step must be dewatered in a filter press and tested for heavy-metal leachability per EN 12457-2 before non-hazardous landfill disposal.Radiolabeling of the tetrahydrobenzothiazole scaffold with carbon-11 at the propionamide carbonyl position for positron emission tomography tracer development proceeds via a one-pot [¹¹C]carbon monoxide insertion into the 6-iodo precursor using a GE TRACERlab FX C Pro synthesis module. The reaction mixture contains 0.4 mg palladium(II) acetate, 1.2 mg Xantphos ligand, and 10 μL 1,8-diazabicyclo[5.4.0]undec-7-ene in 300 μL anhydrous tetrahydrofuran, pressurized with [¹¹C]CO to 35 MPa and heated to 120 °C for 5 minutes. Semi-preparative HPLC purification (Phenomenex Luna C18, 250 × 10 mm, 10 μm, mobile phase 35% ethanol in 50 mM ammonium formate buffer pH 4.5, flow 4 mL/min) isolates the radiolabeled product with a retention time of 14.2 minutes. Radiochemical purity exceeding 98% and molar activity of 45–80 GBq/μmol at end-of-synthesis are achievable when the precursor is stored under argon at –20 °C with desiccant and used within 72 hours of purification. The radiometabolite analysis protocol requires a dedicated solid-phase extraction method (Waters Oasis HLB, 3 cc/60 mg, conditioned with methanol then water) of plasma samples drawn at 5, 15, 30, and 60 minutes post-injection from preclinical rodent models, followed by radio-HPLC co-injection with the cold reference standard. Published data for this specific precursor in clinical-grade current Good Manufacturing Practice radiosynthesis is limited to 3 documented runs meeting the release criteria of the European Pharmacopoeia monograph EP 0125 for radiopharmaceuticals; each run must document the filter-integrity test (bubble-point test, Millipore Millex-GV 0.22 μm, minimum 3.45 bar) and the residual-solvent analysis for tetrahydrofuran (≤ 720 ppm), ethanol (≤ 5000 ppm), and formamide (≤ 220 ppm) by headspace gas chromatography with flame-ionization detection.

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Certification & Compliance

S-2-Amino-6-Propionamide-4,5,6,7-Tetrahydrobenzothiazole 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

A synthesis-scale chiral building block, S-2-Amino-6-propionamide-4,5,6,7-tetrahydrobenzothiazole (CAS 106006-84-2, molecular formula C₁₀H₁₅N₃OS, molecular weight 225.31 g·mol⁻¹) serves as the primary penultimate intermediate in the convergent route to the non-ergoline dopamine agonist pramipexole dihydrochloride monohydrate. The molecule comprises a partially saturated 4,5,6,7-tetrahydrobenzothiazole core bearing an (S)-2,6-diamino substitution pattern, where the 6-amino group is chemo-selectively acylated with a propionamide side chain. This regio- and stereochemical arrangement distinguishes the product from the corresponding (R)-antipode and the racemic modification, both of which are encountered in unoptimized synthetic streams and must be resolved prior to condensation with the final propionaldehyde synthon. Industrial supply chains typically qualify this intermediate against a specification of ≥99.0% chemical purity by HPLC (UV detection at 254 nm) and ≥99.5% enantiomeric excess (ee) by chiral stationary-phase HPLC, employing a polysaccharide-based column (e.g., Chiralpak AD-H, 250 × 4.6 mm) with a hexane/ethanol/diethylamine mobile phase at 1.0 mL·min⁻¹ and 25°C. Absolute configuration is verified by correlation of the observed specific rotation ([α]D²⁰ = −62° ± 2°, c = 1.0, methanol) against a working standard traceable to a certified reference material produced in accordance with ICH Q7 Good Manufacturing Practice guidance for active pharmaceutical ingredients.

Interconversion Kinetics and Solid-State Stability Envelope

Maintenance of enantiomeric integrity during storage and inter-stage transfers constitutes the principal specification-compliance risk. Differential scanning calorimetry (DSC) at a heating rate of 10 K·min⁻¹ under nitrogen purge (50 mL·min⁻¹) reveals a sharp melting endotherm with onset at 218–220°C, accompanied by an exothermic decomposition event above 230°C. Thermogravimetric analysis (TGA) registers negligible mass loss (<0.1%) up to 180°C, confirming the absence of solvate or hydrate forms under standard drying conditions. However, exposure of the solid to relative humidity above 75% at 40°C for 72 hours has been observed to induce partial racemization at the C6 stereocentre, with ee erosion from 99.6% to 97.8% in open-vessel stability chambers. The proposed mechanism proceeds via reversible imine-enamine tautomerism of the free 2-amino group facilitated by a water-mediated proton shuttle, a pathway suppressed by double polyethylene-lined, heat-sealed aluminium laminate packaging under nitrogen headspace. Accelerated stability studies conducted in accordance with ICH Q1A(R2) conditions (40°C/75% RH, 6 months) demonstrate that product stored in this configuration retains enantiomeric excess within the initial specification window, while product stored in low-density polyethylene containers alone exhibits a mean ee decline of 0.4% per month. Production-scale dryers (conical vacuum dryer, 2 m³ working volume, jacket temperature 50°C, ultimate vacuum ≤10 mbar) are operated with a nitrogen bleed to maintain outlet gas dew point below −40°C, terminating the drying cycle when residual solvents comply with ICH Q3C Option 1 limits.

What Distinguishes the (S)-Enantiomer from Racemic and (R)-Forms in Multistep Synthesis?

The racemic modification, (±)-2-amino-6-propionamide-4,5,6,7-tetrahydrobenzothiazole, introduces a mandatory chiral resolution step after final coupling to pramipexole base, typically employing L-(+)-tartaric acid in ethanol/water mixtures to isolate the desired (S)-enantiomer as the dihydrochloride salt. This post-synthetic resolution reduces overall yield by a minimum of 50% and generates an equivalent mass of the unwanted (R)-isomer requiring disposal or recycling via a separate racemization-re-resolution loop. Incorporation of the enantiopure S-intermediate eliminates the resolution operation, compressing the process mass intensity (PMI) for the registered starting material-to-API sequence from a benchmark 22–28 kg·kg⁻¹ to approximately 15–18 kg·kg⁻¹ when coupled with direct reductive amination in tetrahydrofuran using sodium triacetoxyborohydride and propionaldehyde at 0–5°C. The (R)-enantiomer, isolated from mother liquors of diastereomeric salt resolution, cannot be converted into active pharmaceutical substance without an additional multistep sequence involving oxidation to the corresponding ketone and asymmetric reductive amination; consequently, its commercial value is confined to use as a reference standard for enantiomeric purity method validation, where a certified content of ≥99.5% ee and ≤0.05% (S)-isomer as per Ph. Eur. monograph 2608 for pramipexole dihydrochloride is required.

Comparative Enantiomeric Forms: Critical Quality Attributes
Attribute	S-Enantiomer (Target)	Racemate	R-Enantiomer
Specific rotation [α]D²⁰ (c=1, MeOH)	−62° ± 2°	0° ± 0.5°	+62° ± 2°
Enantiomeric excess (ee) specification	≥99.5%	Not applicable	≥99.5% (reference use)
Melting range (DSC onset)	218–220°C	204–208°C	218–220°C
Application in pramipexole synthesis	Direct API formation	Requires resolution	Reference standard only
ICH Q3A qualification requirement	Full	Not qualified	Not qualified

Bulk intermediate entering the final coupling stage is typically specified for water content (Karl Fischer coulometric titration, ≤0.3% w/w), residual palladium from the preceding asymmetric hydrogenation step (ICP-MS, ≤10 ppm) and sulphated ash (≤0.1%). The palladium limit is critical: concentrations above 20 ppm have been correlated with formation of a des-propionyl impurity during acidic salt formation due to catalytic hydrogenolysis of the amide bond, detectable as 2,6-diamino-4,5,6,7-tetrahydrobenzothiazole at levels exceeding the 0.10% identification threshold specified in ICH Q3B (R2). Operational integration into a registered manufacturing process requires verification of polymorphic consistency. Powder X-ray diffraction (XRPD) patterns of the S-enantiomer crystallised from isopropanol/water (90:10 v/v) exhibit characteristic reflections at 2θ = 9.8°, 12.4°, 17.2°, 20.1°, and 24.6° using Cu Kα radiation. A second polymorph, obtained by rapid cooling from acetone solution, shows peak shifts with a new reflection at 2θ = 11.7° and is metastable, converting to the thermodynamically stable form upon slurry equilibration at 25°C in isopropanol within 8 hours. The API manufacturer’s filing (Drug Master File, Type II) will normally reference the stable polymorph exclusively; thus, crystallisation isolation must include a controlled cooling ramp (0.3 K·min⁻¹ from 55°C to 5°C) and a 4-hour isothermal hold to avoid entrapment of the kinetic form.

When Amine Coupling Selectivity Dictates Reactor Configuration

The presence of two nucleophilic amino groups—the aromatic 2-NH₂ and the aliphatic 6-NH₂—imposes strict chemoselectivity demands on the acylation step used to install the propionamide side chain. In the most common manufacturing sequence, the diamine precursor (S-2,6-diamino-4,5,6,7-tetrahydrobenzothiazole) is treated with 1.05 equivalents of propionyl chloride in dichloromethane at −10 to −5°C, utilising N-methylmorpholine as an auxiliary base to scavenge evolved hydrogen chloride. Under these conditions, the aliphatic amine at C6 reacts preferentially (rate constant ratio k₆/k₂ ≈ 8.5:1 at −10°C as determined by reaction calorimetry), but the selectivity is highly sensitive to local stoichiometric gradients. Pilot-plant campaigns performed in a 500 L glass-lined reactor (Pfaudler, retreat curve impeller, tip speed 2.8 m·s⁻¹) documented that point addition of propionyl chloride at the liquid surface without sufficient agitation (Reynolds number < 5,000) generated transient hot spots where the local acid chloride excess produced 3–5% of the over-acylated bis-propionamide impurity. Reconfiguration to subsurface addition via a dip pipe terminating 50 mm above the impeller blade and maintenance of agitator speed yielding Re ≥ 8,000 reduced this impurity to ≤0.15%, below the reporting threshold for the subsequent API. Published data for this specific configuration is limited to patent exemplifications and process development reports; however, consistent application of the subsurface addition protocol across multiple contract manufacturing organisations has resulted in batch-to-batch purity reproducibility with a relative standard deviation of 0.18% over 42 consecutive commercial lots. The isolated S-2-amino-6-propionamide intermediate precipitates directly from the reaction mixture upon drowning into cold water (0–5°C) and is recovered by centrifuge filtration (basket centrifuge, 800 mm diameter, 1000 rpm) with a typical wet cake loss-on-drying of 22–25% and dried under vacuum as described.

Typical Released Specification and Reference Methodology
Parameter	Specification Limit	Method Reference
Appearance	White to off-white crystalline powder	Visual, Ph. Eur. 2.2.1
Assay (anhydrous basis)	98.5–101.0%	HPLC, Ph. Eur. 2.2.29 (ext. standard)
Enantiomeric excess	≥99.5%	Chiral HPLC (Chiralpak AD-H), USP <621>
Individual unspecified impurity	≤0.10%	HPLC area %, ICH Q3B(R2)
Water content	≤0.3%	Karl Fischer, Ph. Eur. 2.5.12
Residual Pd	≤10 ppm	ICP-MS, Ph. Eur. 2.4.20
Sulphated ash	≤0.1%	Ph. Eur. 2.4.14
Residual solvents: dichloromethane	≤600 ppm	GC-HS, ICH Q3C Option 1

Storage and distribution logistics incorporate validated temperature-controlled containers (2–8°C) for intercontinental shipment during the Northern Hemisphere summer months, as prolonged exposure to >40°C within standard unrefrigerated sea freight containers has been associated with minor agglomerate formation and a shift in particle size distribution (D90 increase from 120 µm to 350 µm). Such particle growth, while not degrading chemical purity, slows dissolution kinetics in the subsequent reductive amination step, extending the required hold time from 2 hours to over 6 hours to achieve complete conversion as monitored by FTIR disappearance of the propionaldehyde carbonyl band at 1725 cm⁻¹. Sites serving as terminal users are advised to requisition an on-receipt analytical certificate including full monograph testing before releasing the lot into the controlled production area.