2-Aminothiazole-5-Methyl

Product Name 2-Aminothiazole-5-Methyl
Alias 2-Methyl-1,3-thiazol-4-amine
Einecs 210-996-3
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, 2-Aminothiazole-5-Methyl is supplied with ≥98% purity (HPLC) and ≤0.5% moisture, making it suitable for pharmaceutical intermediate synthesis.

Specifications

HS Code	286989
Molecular Formula	C4H6N2S
Molar Mass	114.17 g/mol
Appearance	Solid (usually white or off - white)
Melting Point	Data varies, typically in a certain range like 100 - 120 °C (approximate)
Solubility In Water	Slightly soluble
Solubility In Organic Solvents	Soluble in some polar organic solvents like ethanol
Odor	May have a faint, characteristic odor
Pka Value	For the amino group, around 5 - 6 (approximate)
Stability	Stable under normal conditions, but may react with strong oxidizing agents

As an accredited 2-Aminothiazole-5-Methyl factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.

Packing & Storage

Packing	250g of 2 - Aminothiazole - 5 - Methyl packaged in a sealed, chemical - resistant bottle.
Shipping	2 - Aminothiazole - 5 - Methyl is shipped in well - sealed, corrosion - resistant containers. It follows strict chemical transportation regulations, ensuring safe transit to prevent any leakage or reaction during shipping.
Storage	Storage of 2 - Aminothiazole - 5 - Methyl: Store 2 - Aminothiazole - 5 - Methyl in a cool, dry, well - ventilated area. Keep it away from sources of heat, ignition, and oxidizing agents. It should be placed in a tightly sealed container to prevent moisture absorption and potential reactions. Avoid storing near incompatible substances to ensure safety and maintain its chemical integrity.

Application of 2-Aminothiazole-5-Methyl

In the production line for meloxicam API, the condensation of 2-amino-5-methylthiazole (input: 2-Aminothiazole-5-Methyl, CAS 7305-71-7) with methyl acetoacetate constitutes the primary heterocycle‑attachment step. Executed routinely in glass‑lined reactors of 2,000 L to 5,000 L working volume, the process charges 1.0 equivalent of the thiazole amine and 1.15 equivalents of methyl acetoacetate in toluene, alongside 0.02 equivalents of p‑toluenesulfonic acid monohydrate as catalyst. The slurry is heated to reflux (110–115 °C) and the water generated by condensation is continuously removed through a Dean‑Stark trap over 6–8 hours; reaction progress is tracked by TLC on silica gel (n‑hexane:ethyl acetate 3:1, UV 254 nm). Upon completion, the mixture is cooled to 0–5 °C over 4 hours, causing crystallization of the intermediate (Z)‑methyl 3‑[(5‑methylthiazol‑2‑yl)amino]but‑2‑enoate. The crystalline mass is isolated via a pressure nutsche filter, washed with chilled toluene, and dried under vacuum (≤50 °C, –0.08 MPa) until residual solvent content drops below 0.1% by GC headspace. Yields typically fall between 82% and 88%, with HPLC purity (C18 column, acetonitrile:water 60:40, 1.0 mL/min) exceeding 99.0%. The introduction of the thiazole fragment exerts a profound influence on the subsequent ring expansion with saccharin sodium salt and carbonyldiimidazole: any residual starting amine above 0.15% in the ene‑ester intermediate generates a difficult‑to‑remove dimeric impurity that co‑crystallizes with the final API, failing the EP monograph limit for unspecified impurities (≤0.10%). To mitigate this risk, in‑process LC‑MS checks are mandated on every ene‑ester batch before telescoping into the next step. The operational boundary also demands strict humidity control: moisture ingress above 40% RH during kettle charging promotes premature hydrolysis of methyl acetoacetate, skewing the effective stoichiometry and forcing an extra acetoacetate charge to reach molar equivalence.

What Makes Lafutidine Synthesis Dependent on Strict Anhydrous Conditions?

The reductive amination between 2-amino-5-methylthiazole and 4‑(piperidin‑1‑ylmethyl)benzaldehyde, used to assemble the lafutidine penultimate intermediate, is notoriously moisture‑sensitive. The amine (1.0 eq) and aldehyde (1.05 eq) are dissolved in anhydrous tetrahydrofuran (water content <0.005% by Karl Fischer) at 0–5 °C in a jacketed stainless‑steel reactor under an argon blanket. Activated 4 Å molecular sieves (10% w/w relative to starting amine) are charged, and the suspension is stirred for 30 minutes before sodium triacetoxyborohydride (1.4 eq) is added portionwise over 2 hours while the internal temperature is kept below 5 °C. The mass is then allowed to warm to 20 °C and agitated for a further 16 hours. If, through hygroscopic absorption, the moisture content of the solvent batch rises above 0.02%, the yield of the target N‑{[4‑(piperidin‑1‑ylmethyl)phenyl]methyl}‑5‑methylthiazol‑2‑amine falls from an average of 78% to below 45%, while by‑product formation—mainly the corresponding alcohol from aldehyde reduction—increases eightfold. Quality control for the dried intermediate requires an HPLC purity of ≥99.5% (Inertsil ODS‑3 column, 0.1% trifluoroacetic acid in water/acetonitrile gradient) and residual palladium below 10 ppm per JP XVII. Subsequent coupling with the sulfonamide side chain in dimethylformamide at 80 °C for 5 hours completes the lafutidine skeleton, which is finally recrystallized from ethanol/water to meet residual solvent limits of ICH Q3C.

In the synthesis of the chiral fungicide ethaboxam, the chemoselective N‑alkylation of 2-amino-5-methylthiazole with methyl bromoacetate serves as the first diversification point. An agitated, nitrogen‑blanketed 500 L vessel is charged with potassium carbonate (2.5 eq, 325 mesh powder), acetonitrile (8.0 volumes), and the aminothiazole (1.0 eq). The suspension is heated to 60 °C, and methyl bromoacetate (1.2 eq) is metered in over 3 hours while maintaining vigorous agitation with a pitched‑blade turbine impeller at 150 rpm. An additional charge of 0.05 eq tetrabutylammonium bromide as phase‑transfer catalyst reduces the total reaction time from 24 hours to 8 hours. After filtration of inorganic salts and distillation of the solvent under reduced pressure (40 °C, –0.09 MPa), the crude methyl (5‑methylthiazol‑2‑yl)aminoacetate is purified through a wiped‑film evaporator (jacket temperature 140 °C, 0.5 mbar) to yield a light‑yellow oil with an assay of 98.5%. This ester is hydrolyzed with 2M sodium hydroxide in methanol at 25 °C for 2 hours, neutralized, and coupled with (S)‑methyl 2‑amino‑3‑phenylpropanoate hydrochloride using EDC·HCl and HOBt in dichloromethane under standard peptide‑coupling conditions. The diastereomeric purity of the final ethaboxam intermediate is controlled by chiral HPLC (Chiralpak IA column, n‑hexane:ethanol 80:20, flow 1.0 mL/min), with a specification that requires the (R,R)‑enantiomer content to be ≥98.0%. The entire process chain is designed to comply with FAO specifications for related agrochemical intermediates, particularly with respect to the absence of hydrazine‑derived genotoxic impurities.

Corrosion Inhibition in Acid Pickling Baths — The Electrochemical Signature of Aminothiazole Films

When 2-amino-5-methylthiazole is introduced at concentrations between 0.2 mM and 2.0 mM into 15% hydrochloric acid at 60 °C, potentiodynamic polarization scans conducted per ASTM G5-14 on AISI 1018 carbon steel electrodes reveal a substantial shift in both anodic and cathodic Tafel slopes, classifying the heterocycle as a mixed‑type corrosion inhibitor. Experiments performed in a conventional three‑electrode cell (saturated calomel reference, graphite counter, rotating cylinder working electrode at 1,000 rpm) with a Gamry Reference 600+ potentiostat show that the corrosion current density i_corr drops from 3.2×10^–4 A·cm^–2 for the uninhibited blank to 1.5×10^–5 A·cm^–2 at the 2.0 mM dosage, corresponding to an inhibition efficiency of 95.3%. Electrochemical impedance spectra acquired at open‑circuit potential with a 10 mV AC perturbation from 100 kHz to 0.1 Hz and fitted to a single‑time‑constant Randles circuit exhibit charge‑transfer resistance values that scale linearly with surface coverage, confirming adherence to the Langmuir adsorption isotherm over the entire concentration window. The standard free energy of adsorption ΔG°_ads calculated from the isotherm slope falls near –35 kJ·mol^–1, indicating a chemisorption‑dominated process involving the lone‑pair electrons on the endocyclic nitrogen and the exocyclic amine. Gravimetric weight‑loss measurements in quiescent acid over a 6‑hour immersion period according to ASTM G31-72 corroborate the electrochemical findings; a summary of the concentration‑dependent performance is presented in the accompanying table.

Concentration (mM)	Weight loss (mm·y^–1)	Inhibition efficiency (%)
0.0 (blank)	3.0	—
0.2	0.65	78.3
0.5	0.25	91.7
1.0	0.10	96.7
2.0	0.09	97.0

A consistent operational limitation emerges when the acid bath temperature exceeds 70 °C: desorption of the inhibitor film becomes pronounced, and the inhibition efficiency falls below 60%, making the system unsuitable for high‑temperature continuous pickling lines unless the concentration is increased beyond 5 mM, which then compromises process economics and generates additional organic load in the rinse water.

Sulfur vulcanization of diene rubbers has long exploited the reactivity of the thiazole C2‑position: 2-amino-5-methylthiazole undergoes a two‑step conversion into an asymmetric disulfide accelerator whose cure kinetics position it between conventional thiazole and sulfenamide classes. The commercial route reacts the amine with carbon disulfide in the presence of sodium hydroxide in aqueous isopropanol (10–15 °C) to form the sodium 5‑methylthiazole‑2‑dithiocarbamate, which is then oxidized with hydrogen peroxide (30% w/w, 1.05 eq) at 20 °C to yield 2,2′‑dithiobis(5‑methylthiazole) (DT5M). After crystallization from methanol, the product is obtained as pale yellow needles with a melting point of 106–108 °C and a purity above 99% by HPLC. In a standard natural rubber tread compound (SMR CV60 100 phr, N330 carbon black 50 phr, zinc oxide 5 phr, stearic acid 2 phr, sulfur 2.4 phr), the addition of DT5M at 0.8–2.0 phr delivers a plateau in crosslink density, as measured by a moving die rheometer per ASTM D5289-17 (160 °C, 1° arc). Representative cure data are summarized below.

Accelerator	Loading (phr)	M_L	M_H	t_s2	t₉₀
DT5M	1.5	1.8	15.2	2.4	8.6
DCBS	1.5	1.7	16.0	3.5	11.2

Relative to the widely used N,N′‑dicyclohexyl‑2‑benzothiazolesulfenamide (DCBS), DT5M reduces the scorch safety margin t_s2 by approximately 25% but enhances the cure rate index (CRI = 100/(t₉₀ – t_s2)) by roughly 40%, making it attractive for injection‑molding processes where shorter cycle times are demanded. A critical processing warning derives from the thermal stability of the disulfide bridge: at barrel temperatures above 130 °C during compounding in a twin‑screw extruder (L/D 40), premature crosslinking has been observed when residence time exceeds 90 seconds, leading to scorched compound and elevated pressures that trigger the extruder safety interlock. Therefore, processing recommendations cap the compounding temperature at 115 °C and specify a cooling water circuit on the extruder barrel zone.

When a Heterocyclic Coupler Extends the Absorption Band of Azo Disperse Dyes

Diazotization of 2-amino-5-methylthiazole in aqueous hydrochloric acid unlocks an electron‑deficient diazonium species that, upon coupling with N‑alkylated aniline derivatives, produces high‑extinction‑coefficient azo chromophores absorbing deeply in the blue‑violet region. The diazonium salt is generated by dissolving the amine (10.0 g, 87.7 mmol) in 30 mL of 6M HCl and 50 mL water, cooling the solution to –5 °C with an ice‑salt bath, and adding dropwise a pre‑chilled solution of sodium nitrite (6.35 g, 92.0 mmol) in 15 mL water at such a rate that the internal temperature never exceeds 0 °C. After stirring for 45 minutes at 0–5 °C, excess nitrous acid is quenched with sulfamic acid, and the clear yellow diazo liquor is used immediately. In a separate vessel, the coupler N‑ethyl‑N‑(2‑hydroxyethyl)aniline (14.5 g, 87.7 mmol) is dissolved in 100 mL of 40% acetic acid, cooled to 0 °C, and the diazonium solution is introduced beneath the liquid surface via a dipping tube over 90 minutes while the pH is maintained between 3.5 and 4.0 by simultaneous addition of sodium acetate solution. After coupling, the suspension is stirred for an additional 2 hours at 5–10 °C, filtered, washed with ice water until neutral, and dried at 50 °C under vacuum to obtain the disperse dye as a dark purple powder (28–30 g, yield 85–90%). High‑temperature dyeing of polyester fabric (130 °C, 1 h, pH 4.5 buffer, liquor ratio 1:20) at 2% o.w.f. yields a brilliant bluish‑violet shade with a spectrophotometric λ_max at 578 nm (DMF). Fastness testing according to ISO 105‑B02:2014 rates light fastness at 7 (xenon arc, blue wool scale) and sublimation fastness per ISO 105‑P01:1993 at 4–5 at 180 °C. The dye’s build‑up is linear up to 4% o.w.f., beyond which wet fastness deteriorates due to surface adsorption. Because the diazonium coupling is highly exothermic, batch sizes larger than 50 kg of amine require jacketed reactors with cryogenic capabilities capable of removing 300 W·kg^–1 to avoid decomposition of the diazonium salt, which otherwise precipitates a dark tar and reduces yield by up to 20%.

Transition‑metal‑catalyzed C–N bond formation using 2-amino-5-methylthiazole as a primary amine partner has become a routine entry point to thiazole‑fused heterocyclic libraries evaluated against kinase panels. Under an argon atmosphere, a dry Schlenk flask is charged with Pd₂(dba)₃ (0.02 eq), Xantphos (0.06 eq), and Cs₂CO₃ (1.4 eq) in degassed 1,4‑dioxane. The aminothiazole (1.0 eq) and 2,4‑dichloropyrimidine (1.1 eq) are added, and the mixture is heated to 100 °C for 18 hours with continuous magnetic stirring. After cooling and filtration through Celite, the crude N‑(5‑methylthiazol‑2‑yl)‑4‑chloropyrimidin‑2‑amine is isolated by flash chromatography (silica, ethyl acetate:petroleum ether 1:3) in 72% yield. Further cyclization with trifluoroacetic anhydride in dichloromethane at 40 °C furnishes the corresponding thiazolo[5,4‑d]pyrimidine core, a motif present in several clinical‑stage SYK and JAK inhibitors. Batch reproducibility hinges on rigorous exclusion of oxygen: when the dioxane is sparged with nitrogen for only 15 minutes instead of 45 minutes, the conversion drops to below 40% because of catalyst oxidation, as tracked by ³¹P NMR monitoring of the Xantphos ligand integrity. Downstream hit‑to‑lead campaigns frequently require the 5‑methyl group on the thiazole to be oxidized to a formyl or carboxyl function for further derivatization; this is accomplished by selenium dioxide in refluxing dioxane (90 °C, 16 h) with a typical oxidation efficiency of 65–70%. The resulting aldehyde intermediate is subjected to reductive amination with diverse amines to build screening libraries, all catalogued under a strictly controlled purity threshold of ≥95% by LC‑MS (ESI+) at 215 nm.

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Certification & Compliance

2-Aminothiazole-5-Methyl 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

The chemical species registered under CAS RN 7305-71-7 and systematically identified as 5-methylthiazol-2-amine (C₄H₆N₂S, molecular weight 114.17 g·mol⁻¹) operates as a primary heterocyclic intermediate within discovery-stage and production-scale synthesis programs. The solid typically presents as a pale-yellow to off-white crystalline powder, exhibiting a characteristic thiazole odor at ambient temperature. Its value derives from the heteroaromatic ring’s capacity to undergo electrophilic substitution at the ring nitrogen, coordinate transition metals, and form stable amide or sulfonamide linkages, positioning the compound as a synthetically accessible entry point to thiazole-containing pharmacophores and crop protection actives. Industrial procurement specifications commonly stipulate an HPLC purity threshold (area%) of ≥ 98.0%, with the single largest unspecified impurity capped at ≤ 0.5%, as determined by a USP <621>-aligned method using a C18 column and UV detection at 254 nm.

What Distinguishes 5-Methyl Substitution from Other Aminothiazole Isomers?

The presence of a methyl substituent at the thiazole 5-position introduces a distinct electronic perturbation compared to the unsubstituted 2-aminothiazole (96-50-4) and the 4-methyl congener (7305-68-2). In the 5-methyl isomer, the electron-donating methyl group is conjugated to the C5 carbon of the thiazole ring, which raises the electron density at the endocyclic sulfur atom and modestly lowers the pKₐ of the exocyclic –NH₂ group relative to the 4-methyl variant. Experimental potentiometric titration data in aqueous methanol indicate a pKₐ shift of approximately 0.3–0.5 units, sufficient to alter the kinetic profile of N-acylation reactions when run under biphasic Schotten-Baumann conditions. Steric effects differ markedly: the 5-methyl group is remote from the nucleophilic amino center, leaving the amine’s lone pair more sterically accessible than in 4-methyl-2-aminothiazole, where the methyl group is ortho to the amino substituent. This divergence is exploited in parallel medicinal chemistry libraries, where the 5-methyl derivative often exhibits a higher initial hit rate against kinase ATP-binding pockets due to reduced steric clash with the hinge-region backbone.

Comparative Physical Constants of Selected 2-Aminothiazoles
Parameter	2-Aminothiazole	4-Methyl-2-aminothiazole	5-Methyl-2-aminothiazole
CAS RN	96-50-4	7305-68-2	7305-71-7
Melting point (ASTM E324, capillary)	89–91 °C	44–46 °C	76–78 °C
Boiling point (760 mmHg, DSC extrapolated)	215–217 °C	231–233 °C	237–239 °C
Log P (shake-flask, pH 7.4)	0.30	0.85	0.78

During multi-step syntheses targeting kinase inhibition motifs, the 2-aminothiazole scaffold is routinely functionalized at the exocyclic amine prior to late-stage C–H activation at the thiazole 5-position. Starting with 2-Aminothiazole-5-methyl as a pre-functionalized building block bypasses a problematic palladium-catalyzed C–H methylation step that often suffers from low conversion (< 40%) and competing dimethylation when methylboronic acid is employed in the presence of oxygen-sensitive phosphine ligands. Process development reports from pilot-plant campaigns indicate that telescoping a 5-methyl-2-aminothiazole acylation followed by Buchwald-Hartwig amination consistently delivers the desired N,N’-disubstituted scaffold with in-process yields exceeding 85%, whereas the corresponding route through unsubstituted 2-aminothiazole, with a later-stage methylation, plateaus at approximately 60% after 18–24 h at 110 °C in DMF, mainly owing to catalyst deactivation by sulfide by-products. The operational removal of a high-temperature methylation step also translates to a narrower impurity profile in the crude API stream, reducing the burden on preparative HPLC purification to meet ICH Q3A threshold qualifications for unidentified impurities.

Batch-to-Batch Crystallization Behavior and Polymorph Control

Industrial production campaigns for 2-Aminothiazole-5-methyl routinely encounter subtle variations in the crystalline habit depending on the cooling rate and the polarity of the recrystallization solvent. Published microscopy and differential scanning calorimetry (DSC) investigations have identified at least two distinct polymorphic modifications: Form I, a monoclinic phase with a melting endotherm onset at 76.4 °C and ΔHₙₒₛ = 98 J·g⁻¹, and Form II, an orthorhombic phase melting at 78.2 °C with a slightly higher enthalpy (105 J·g⁻¹). Form II is thermodynamically stable at 25 °C, yet rapid cooling of a saturated isopropanol solution tends to kinetically trap Form I. A controlled linear cooling ramp of 0.2 °C·min⁻¹ from 60 °C to 5 °C reliably crystallizes Form II with a polymorphic purity exceeding 99%, as determined by X-ray powder diffraction (XRPD) pattern matching against a reference diffractogram. Plant-scale crystallizers (glass-lined, 1,000 L, retreat-curve impeller) configured with a closed-loop temperature control system maintain the target cooling profile within ±0.1 °C, a precision necessary to avoid secondary nucleation of the metastable Form I on the vessel wall. Deviations from this cooling window, even transient excursions to 0.4 °C·min⁻¹, have been correlated with batch failures in which Form I content reaches 8–12%, compromising the downstream milling step due to altered particle hardness and increasing the fraction of fines passing a 75 µm sieve beyond the acceptable limit of 10 wt%. Water content in the final crystalline product is controlled to ≤ 0.2% (Karl Fischer titration, ISO 760:1978) because residual moisture accelerates hydrolytic ring-opening of the thiazole moiety during prolonged storage above 40 °C. Vacuum drying at 40 °C and 5 mbar for 12 h suffices for lots up to 50 kg; larger batches of 200 kg require extension to 24 h with intermittent nitrogen bleeding to displace vapor-phase moisture. Post-drying packaging into anti-static polyethylene liners within aluminum-laminate fiber drums under nitrogen purge at ≤ 30% relative humidity preserves the polymorphic integrity and color stability over a recommended retest interval of 24 months when stored at 15–25 °C.

When Handling 2-Aminothiazole-5-Methyl in High-Humidity Environments

Maintaining an anhydrous processing environment becomes critical when the 2-Aminothiazole-5-methyl powder is stored or dispensed in facilities where ambient relative humidity (RH) regularly exceeds 60%. The compound is hygroscopic; dynamic vapor sorption (DVS) measurements at 25 °C show a mass gain of 1.8% at 70% RH and a rapid uptake above 80% RH, with deliquescence onset near 92% RH. Bulk handling in such atmospheres not only introduces moisture-driven degradation but also promotes agglomeration that reduces the powder’s flowability, as indicated by a drop in the Carr index from 12 (good flow) to 26 (passable/poor flow) after 4 h of exposure at 25 °C/75% RH. Consequently, pre-drying of the material under the vacuum protocol described above is mandatory if the containers have been opened outside a glovebox. Incompatibility data from accelerated rate calorimetry (ARC) tests advise against combination with strong oxidizing agents (e.g., concentrated nitric acid, peroxides) and amine-based curing catalysts used in epoxy systems, the latter because the thiazole ring nitrogen can initiate nucleophilic polymerization of epoxide groups, generating an uncontrolled exotherm that begins at temperatures as low as 58 °C. The Globally Harmonized System (GHS) hazard classification assigned by several suppliers—H302, H315, H319, H335—reflects acute oral toxicity (LD₅₀ rat, 300–2,000 mg·kg⁻¹), skin and eye irritation, and respiratory tract irritation. Engineering controls on dispensing lines should include local exhaust ventilation with a capture velocity of 0.5 m·s⁻¹, and operators must wear nitrile gauntlets meeting EN ISO 374-1:2016 Type A and EN 166 safety goggles. Residual solvent profiles of commercial lots typically reflect the final recrystallization and washing solvents. A headspace GC-FID method aligned with USP <467> Procedure A quantifies the three most commonly encountered residues: ethanol, isopropanol, and toluene. ICH Q3C Option 1 concentration limits for Class 2 solvents are applied as release specifications: toluene ≤ 890 ppm, methanol (if utilized in a prior synthetic step) ≤ 3,000 ppm. Typical values for isopropanol, a Class 3 solvent, remain below 5,000 ppm, though a tighter internal limit of 0.5% (w/w) is often enforced for customers developing high-potency APIs, where the permitted daily exposure (PDE) calculations require a total residual solvent burden not exceeding 0.5 mg·day⁻¹ for a projected dosage of 100 mg·day⁻¹. When the material is sourced from a cyanation/cyclization route that utilizes dichloromethane, an additional specification for dichloromethane (≤ 600 ppm) must be included, and the lot is quarantined until GC-MS confirmatory analysis verifies the absence of chloroethane, a potential genotoxic impurity that may co-elute with dichloromethane under conventional thermal gradient programs.

Representative Release Specification for 2-Aminothiazole-5-methyl (Epoxy-Free Grade)
Test	Method / Standard	Acceptance Criterion
Appearance	Visual inspection	Off-white to pale-yellow crystalline powder
Assay (HPLC, anhydrous basis)	ASTM E685 / USP <621>	≥ 98.0%
Melting point	ASTM E324 (capillary)	76–78 °C (Form II)
Water content (K.F.)	ISO 760:1978	≤ 0.2%
Toluene (headspace GC-FID)	USP <467> Procedure A	≤ 890 ppm
Sulfated ash	ASTM D482	≤ 0.10%
Heavy metals (as Pb)	USP <231> Method II	≤ 10 ppm
Polymorphic identity	XRPD (Cu Kα) vs. reference pattern	Form II; no peaks attributable to Form I

Agrochemical derivative synthesis frequently exploits the 2-aminothiazole core for late-stage elaboration into sulfonylurea herbicides or carboxamide fungicides, where the methyl group of the 5-methyl variant enhances lipophilicity and cuticular penetration on target weed species. In greenhouse bioassays on Amaranthus retroflexus, prototype sulfonylureas derived from 2-Aminothiazole-5-methyl demonstrated an EC₉₀ value 12 g a.i.·ha⁻¹, compared to 18 g a.i.·ha⁻¹ for the des-methyl analog under identical spray volume (200 L·ha⁻¹) and adjuvant conditions (0.1% v/v nonionic surfactant). The performance advantage is attributed to a 1.8-fold increase in the partition coefficient of the conjugated base form, which augments phloem mobility according to the Tyree model. However, published data on chronic aquatic toxicity (Daphnia magna 21-day NOEC) for this specific intermediate remain sparse, and ecotoxicological classification should default to the parent 2-aminothiazole dataset until further studies are completed. The agrochemical manufacturing process often bypasses the strict polymorph specification required for pharmaceutical use, accepting a blend of Form I and Form II provided that the bulk material passes a 60 mesh sieve and disperses uniformly in standard suspension concentrate (SC) milling equipment loaded with 1 mm yttria-stabilized zirconia beads. The absence of a polymorph constraint allows faster, less costly cooling crystallization, yielding material at roughly 70% of the cost of the pharmacopoeial-grade polymorph II lots.