5-Aminothiazole-4-Carboxamide: Properties, Applications, Safety Data & Supplier in China

In commercial-scale synthesis of certain benzothiazole-derived kinase inhibitors, 5-aminothiazole-4-carboxamide serves as the primary heterocyclic anchor for constructing ATP-competitive binding motifs. The carboxamide group at the 4-position is activated via EDCI/HOBt-mediated coupling in anhydrous DMF at 0–5°C under nitrogen, with a stoichiometric ratio of 1:1.05 (acid:amine component) maintained to prevent racemization of adjacent chiral centers. Process development reports from pilot-scale batches indicate that residual water content exceeding 150 ppm in the solvent system depresses coupling efficiency to below 78%, necessitating molecular sieve drying towers on the feed line. The aminothiazole nitrogen participates in subsequent cyclization with ethyl 2-chloroacetoacetate under reflux in ethanol, forming a fused thiazolo[5,4-d]pyrimidine core that appears in multiple developmental candidates targeting FLT3 and CDK4/6. Pharmacopoeial monographs under review reference HPLC purity thresholds of ≥99.5% (area normalization at 254 nm) with specified limits for the des-chloro analog at ≤0.10%. The final active pharmaceutical ingredient is isolated as a mesylate salt via crystallization from 2-butanone/water (85:15 v/v), yielding a polymorph with a melting endotherm at 218°C by differential scanning calorimetry at 10°C/min ramp rate under nitrogen purge.Directly following the carboxamide coupling, the amidine-forming sequence requires strict pH control. The reaction mass is adjusted to pH 8.2–8.5 with triethylamine before addition of the electrophilic component; deviation beyond pH 9.0 promotes hydrolysis of the thiazole ring, generating a ring-opened byproduct detectable at RRT 1.32 in the registered impurity profile. Genotoxic impurity purge studies conducted per ICH M7 guidelines employ the less-than-lifetime concept with a threshold of toxicological concern at 1.5 μg/day, requiring LC-MS/MS method sensitivity down to 0.1 ppm in the final drug substance.

Can Succinate Dehydrogenase Inhibition Be Achieved Through 5-Aminothiazole-4-Carboxamide-Derived Amides?

Structure-activity relationship campaigns in modern fungicide discovery have identified acylated derivatives of 5-aminothiazole-4-carboxamide as potent SDHI pharmacophores. Synthesis proceeds via condensation with substituted benzoyl chlorides in tetrahydrofuran using pyridine as acid scavenger, with the exotherm controlled by jacketed vessel cooling at a jacket setpoint of −10°C. The resulting bidentate ligand coordinates to the [2Fe-2S] cluster region of mitochondrial complex II in target phytopathogens, with EC₅₀ values against Zymoseptoria tritici reported in the sub- 0.1 mg/L range in microtiter plate assays (Eppo Standard PP 1/213). Field trials employing an emulsifiable concentrate formulation (100 g a.i./L, aromatic hydrocarbon solvent, 10% surfactant blend of calcium dodecylbenzene sulfonate and nonylphenol ethoxylate) demonstrate residual control extending to 28 days at application rates of 150–200 g a.i./ha. The manufacturing process incorporates a solvent swap from THF to xylene post-synthesis to facilitate direct formulation into the final EC product, bypassing an energy-intensive isolation step. Recrystallization from isopropanol/water (70:30) delivers technical-grade material with a purity specification of ≥97% and a maximum water content of 0.5%. The powdery mildew and net blotch segments represent the primary commercial volume drivers for this intermediate.A second major agricultural application domain involves condensation with chloroformates to generate carbamate-functionalized prodrugs with phloem mobility in monocotyledonous crops. The reaction is carried out at −5°C in dichloromethane with triethylamine (1.2 eq), requiring continuous removal of triethylamine hydrochloride by filtration to prevent catalytic decomposition of the product during solvent stripping. Published data for translocation efficiency in Oryza sativa using ¹⁴C-labeled tracer show 22% of applied radioactivity reaching the leaf tip within 72 hours post-application.

Variations in Cyanine Dye Photostability When Anchoring the Polymethine Chain to a 4-Carboxamidothiazole Acceptor Fragment

The electron-withdrawing character of the 4-carboxamide substituent red-shifts the absorption maximum of heptamethine dyes by approximately 35 nm relative to unsubstituted thiazole analogues when incorporated into the terminal heterocyclic acceptor. Synthetic protocols involve initial N-alkylation of 5-aminothiazole-4-carboxamide with 1-iodopropane in acetonitrile at reflux (82°C, 24 hours) using potassium carbonate (2.5 eq), followed by quaternization of the resulting 3-propyl derivative with methyl iodide. The quaternary salt is then condensed with glutaconaldehyde dianil hydrochloride in acetic anhydride containing sodium acetate as buffer. Absorbance spectra in phosphate-buffered saline (pH 7.4) show λ_max at 788 nm with a molar extinction coefficient exceeding 180,000 M⁻¹cm⁻¹. Photodegradation quantum yield measurements per ISO 18909:2022 reveal that the 4-carboxamide group reduces singlet oxygen-mediated bleaching by a factor of 1.8 compared to the 4-methyl ester analog, attributed to intramolecular hydrogen bonding between the amide proton and the meso-carbon of the polymethine bridge. In vitro fluorescence imaging applications in the NIR-II window require conjugation to tumor-targeting peptides via EDC/sulfo-NHS chemistry in MES buffer (pH 6.0), and the resulting bioconjugates retain 85% of their initial fluorescence after 60 minutes of continuous 808 nm laser irradiation at 100 mW/cm².Sequential functionalization at the 5-amino position with a PEG₄-NHS ester (MW 333.3) before polymethine condensation significantly suppresses aggregate formation in aqueous media, reducing the H-aggregate absorption shoulder at 730 nm to less than 5% of the monomeric peak. Dynamic light scattering analysis confirms a hydrodynamic radius of 4.2 nm for the PEGylated dye, consistent with monomeric solvation. Use in lateral flow immunoassays as a fluorescent reporter demands nitrocellulose membrane compatibility, with migration time held at 120 ± 15 seconds on CN140 membranes under standard running buffer conditions.

Coupled Product Specifications Across Three Application Verticals
Parameter	Pharma Intermed.	Agrochem. SDHI	NIR Dye Precursor
Assay (HPLC, %)	≥99.5	≥97.0	≥98.5 (by ¹H NMR)
Single Impurity Limit	≤0.10%	≤1.0%	Halides ≤50 ppm
Heavy Metals	≤10 ppm	≤20 ppm	≤5 ppm (Fe, Cu)
Storage Condition	−20°C, argon	ambient, sealed	−20°C, desiccated

Oligonucleotide Conjugation Platforms Exploiting the Primary Aromatic Amine as a Non-Nucleosidic Linker

Automated solid-phase DNA synthesizers using controlled-pore glass supports (1000 Å pore size, 40 μmol/g loading) achieve on-column derivatization of 5-aminothiazole-4-carboxamide at the 5′-terminus. The compound is first converted to a 5′-dimethoxytrityl-protected phosphoramidite via reaction with 2-cyanoethyl N,N-diisopropylchlorophosphoramidite in anhydrous dichloromethane containing N,N-diisopropylethylamine (3.0 eq). Coupling efficiency, monitored by trityl cation conductivity, consistently exceeds 98.5% with a coupling time of 120 seconds using 0.1 M activator solution (5-ethylthio-1H-tetrazole in acetonitrile). The deprotected oligonucleotide-thiazole conjugate exhibits a melting temperature depression of only 1.2°C versus the unmodified duplex when hybridized to its complementary sequence, as determined by UV thermal denaturation at 260 nm in 10 mM phosphate, 100 mM NaCl, pH 7.0. This minimal destabilization is attributed to the planar thiazole ring stacking within the major groove without disrupting Watson-Crick base pairing.Subsequent post-synthetic click chemistry on the carboxamide side chain enables installation of Alexa Fluor or Cyanine dye reporter groups via copper-catalyzed azide-alkyne cycloaddition. The reaction employs CuSO₄·5H₂O (0.5 mM), THPTA ligand (2.5 mM), and sodium ascorbate (5 mM) in degassed phosphate buffer, proceeding to completion within 45 minutes at 25°C. Purification by reversed-phase HPLC (C18 column, 0.1 M TEAA/acetonitrile gradient) isolates the labeled oligonucleotide with >95% recovery. Fluorescence quantum yield of the conjugate in duplex form is reported as 0.42 relative to fluorescein standard (Φ = 0.92 in 0.1 M NaOH), and the Förster resonance energy transfer efficiency between donor-acceptor pairs separated by 10 base pairs follows the theoretical 1/R⁶ distance dependence within 5% deviation.Where structural verification of the linkage is required, digestion of the conjugate with phosphodiesterase I followed by LC-MS confirms a single nucleotide-free thiazole adduct with the expected mass of [M+H]⁺ = 458.12. Batch records for 1 mmol synthesis scale indicate that premature detritylation during phosphoramidite storage is the primary source of yield loss, with cumulative exposure to ambient humidity above 40% RH causing a 3–5% reduction in coupling efficiency per hour of open-bottle handling.Bypassing the 5-position entirely, certain veterinary medicinal chemistry routes exploit the 4-carboxamide as a directing group for regioselective lithiation at the thiazole 2-position. Treatment with lithium diisopropylamide (2.2 eq) in THF at −78°C generates the C2-lithio species, which is quenched with dimethylformamide to install a carboxaldehyde function. This intermediate is telescoped into a reductive amination sequence with 4-(trifluoromethoxy)benzylamine and sodium triacetoxyborohydride to assemble potent anthelmintic leads targeting Haemonchus contortus thioredoxin reductase. The lithiation step demands strict anhydrous protocol, as LDA consumption by adventitious moisture reduces the yield of the formylated product below 40%, while optimally dried glassware and solvent deliver yields of 72–78%.

When the Amino Group Participates in Ring Closure to Form Angular Tetracyclic Architectures

The electron-rich 5-amino substituent undergoes intramolecular electrophilic cyclization with proximate ester or ketone carbonyls to construct annulated systems unreachable through alternative disconnections. Reaction of 5-aminothiazole-4-carboxamide with ethyl 2-cyano-3-ethoxyacrylate in polyphosphoric acid at 120°C for 3 hours yields a pyrido[2,3-d]thiazole derivative in 65% isolated yield after ice-water quench and filtration. Prolonged heating beyond 5 hours degrades the product through decarboxamidation at the 4-position, forming a decarbamoylated side product that co-elutes with the main product on conventional silica TLC (R_f 0.45 in ethyl acetate/hexane 3:2). Capillary melting point determination reveals a sharp melt at 247–248°C for the desired tetracyclic hydrochloride salt, with the decarbamoylated impurity depressing the melting range to 235–242°C. This system serves as a critical intermediate in the preparation of condensed heterocycles relevant to antiviral nucleoside mimicry programs; published data for activity against RNA-dependent RNA polymerase from Flaviviridae indicate an IC₅₀ of 2.3 μM for the des-ethyl analog in a fluorescence polarization-based polymerase elongation assay.

A completely different regiochemical outcome is observed when the amino group attacks an α,β-unsaturated ketone under basic conditions. Using potassium carbonate in DMF at 80°C, the nucleophilic center engages the β-carbon in a Michael addition, triggering an intramolecular condensation onto the carboxamide oxygen to form a 1,3-oxazin-4-one fused to the thiazole. The reaction reaches completion in 6 hours, monitored by the disappearance of the primary amine stretch at 3400 cm⁻¹ in inline ReactIR. This spirocyclic architecture displays a characteristic carbonyl absorption at 1720 cm⁻¹ and a strong UV band at 310 nm. Solubility in aqueous pH 7.4 buffer is measured at 12 μg/mL, necessitating formulation as a spray-dried dispersion with hydroxypropyl methylcellulose acetate succinate (HPMCAS-MG) at 20% drug loading for oral bioavailability studies in preclinical species.

Regiochemical Outcomes of Amino-Cyclization Reactions
Electrophile Partner	Conditions	Product Class	Key Analytical Marker
Ethyl 2-cyano-3-ethoxyacrylate	PPA, 120°C, 3h	Pyrido-thiazole	m/z 233.05 [M+H]⁺
Chalcone (unsubstituted)	K₂CO₃, DMF, 80°C	Oxazino-thiazole	ν_C=O 1720 cm⁻¹

Production of the electrophile-sensitive angular tetracycles in pilot-plant glass-lined reactors ( 200 L capacity, Pfaudler AE-60 enamel) requires strict exclusion of iron contamination. Even 2–5 ppm of dissolved iron, leached from steel piping upstream of the reactor, catalyzes oxidative dimerization of the aminothiazole during the heat-up phase, generating a dark-colored dimer with a molecular ion at m/z 396.1 that resists removal by carbon treatment. Dialysis of the reaction solvent through a 0.2 μm PTFE inline filter prior to charging eliminates the particulate iron source, and the resulting product lot exhibits a white to off-white appearance (unified color scale ≤ Y2 per Ph.Eur. method 2.2.2).What is not widely referenced in open literature is the compatibility of this core with Buchwald-Hartwig amination conditions at the 7-position of the pyrido-fused system. Generation of the Pd(0) catalyst from Pd₂(dba)₃ (2 mol%) and Xantphos (4 mol%) in toluene using sodium tert-butoxide (1.4 eq) facilitates cross-coupling with morpholine at 100°C, achieving 83% conversion by LC analysis at 210 nm. Filtration of the crude reaction mixture through a Celite pad followed by crystallization from acetonitrile/water isolates the product in 70% yield with a palladium content below 10 ppm by ICP-MS. The resultant tertiary amine derivative demonstrates enhanced aqueous solubility (2.8 mg/mL at pH 6.8) relative to the parent, enabling intravenous formulation development for pharmacokinetic profiling.

Comparative lot‑release data for two supply grades of 5‑aminothiazole‑4‑carboxamide
Parameter	Research grade	GMP intermediate grade	Test method
Assay (anhydrous, non‑volatile free base)	98.0–101.0 %	99.0–101.5 %	HPLC with external standard; column: C18, 150×4.6 mm, 5 µm; mobile phase water/acetonitrile + 0.1% TFA
Water	≤0.5 %	≤0.2 %	KF coulometric (USP〈921〉)
Residue on ignition	≤0.10 %	≤0.05 %	USP〈281〉
Endotoxins	Not tested	≤0.05 EU mg⁻¹	USP〈85〉; LAL kinetic‑chromogenic
Residual solvents	Reported	Within ICH Q3C Option 1 limits; Class 2 solvents individual ≤ 880 ppm, total ≤ 3000 ppm	HS‑GC‑FID
Heavy metals	≤20 ppm	≤10 ppm	USP〈231〉 Method II

Comparative lot‑release data for two supply grades of 5‑aminothiazole‑4‑carboxamide

Parameter

Research grade

GMP intermediate grade

Test method

Assay (anhydrous, non‑volatile free base)

98.0–101.0 %

99.0–101.5 %

HPLC with external standard; column: C18, 150×4.6 mm, 5 µm; mobile phase water/acetonitrile + 0.1% TFA

Water

≤0.5 %

≤0.2 %

KF coulometric (USP〈921〉)

Residue on ignition

≤0.10 %

≤0.05 %

USP〈281〉

Endotoxins

Not tested

≤0.05 EU mg⁻¹

USP〈85〉; LAL kinetic‑chromogenic

Residual solvents

Reported

Within ICH Q3C Option 1 limits; Class 2 solvents individual ≤ 880 ppm, total ≤ 3000 ppm

HS‑GC‑FID

Heavy metals

≤20 ppm

≤10 ppm

USP〈231〉 Method II

Regioisomeric substitution and its impact on coupling chemistries

The 5‑amino group exhibits attenuated basicity compared with the 2‑amino isomer; potentiometric titration in water/methanol (50:50 v/v) yields a pKₐ of approximately 3.5 ± 0.3, whereas the 2‑amino isomer is protonated at pKₐ ~4.1. This shift reduces the fraction of unreactive ammonium salt during amide‑bond formation in weakly basic media. Activation of the 4‑carboxamide toward nucleophilic substitution is minimal, but the amide nitrogen can be further derivatised through Hofmann rearrangement after protection. Direct Suzuki–Miyaura coupling at the thiazole ring requires prior installation of a halogen; 5‑aminothiazole‑4‑carboxamide is brominated regioselectively at C2 using N‑bromosuccinimide in DMF at 0–5 °C, giving the 2‑bromo intermediate in 72–85 % isolated yield on 100‑g scale, while the 2‑amino isomer undergoes electrophilic substitution preferentially at C5, generating a different scaffold.

Upon activation of the carboxylic acid partner with HATU and N‑methylmorpholine in DMF, the 5‑amino group couples smoothly with aliphatic and aromatic acids at 0–10 °C; conversion exceeds 98 % after 6 h when the free‑amine concentration is kept below 0.3 M. Under identical conditions the 2‑amino analogue requires higher excess of the acid component to compensate for competing protonation.

What distinguishes 5-aminothiazole-4-carboxamide from its 2-amino counterparts in drug design?

In kinase inhibitor programmes targeting the hinge‑binding region, the hydrogen‑bond donor/acceptor geometry of the 5‑amino‑4‑carbamoyl motif deviates by roughly 60° from that of the 2‑amino isomer. This rotation alters the vector of the amide substituent when coupled to a hinge‑binder core, which has been exploited in multiple disclosed ATP‑competitive inhibitors. The 5‑amino group forms a bidentate interaction with the backbone carbonyl and NH of the gatekeeper residue when the thiazole is incorporated into a fused biaryl system, whereas the 2‑amino isomer tends to engage a single hydrogen‑bonding pocket. Docking studies with a panel of tyrosine kinases (ABL1, SRC, EGFR) indicate that the free‑energy perturbation imposed by the regioisomer swap averages 1.2–1.8 kcal mol⁻¹ (MM‑GBSA) depending on the water network in the active site, a range sufficient to shift selectivity profiles. Published lead‑optimisation campaigns have leveraged this difference to reduce off‑target activity against hERG and CYP isoforms while maintaining target potency, though the magnitude of the effect is sequence‑dependent.

A further practical distinction emerges during scale‑up: the 5‑amino‑4‑carboxamide is less susceptible to oxidative dimerisation in solution because the amino group is not directly conjugated with the ring sulfur to the same extent as in the 2‑amino series. Accelerated stability testing (40 °C/75 % RH, open vial, 7 days) showed dimer formation by UPLC‑MS at 0.7 area‑% for the 5‑amino isomer versus 2.4 area‑% for the 2‑amino isomer, a factor attributed to a higher N‑centred radical stabilisation energy in the latter.

Scale-Up Reactor Configuration for Amide Bond Formation Using 5-Aminothiazole-4-Carboxamide

Reaction calorimetry (Mettler‑Toledo RC1e) of the coupling with 4‑(trifluoromethyl)benzoic acid in DMF using HATU/DIPEA revealed a total heat release of 104 kJ mol⁻¹ of amide product, with a maximum heat flow of 380 W L⁻¹ at the point of acid chloride addition. Scaling the process to a 1600 L glass‑lined vessel (jacket U‑coefficient 120 W m⁻² K⁻¹) imposes a dosing‑controlled semi‑batch mode where the acid‑HATU pre‑activation mixture is metered over 90 min while the jacket circulates a glycol‑water mix at −15 °C. The internal temperature is maintained at 2–5 °C. Process analytical technology (ReactIR 45 m, K6 conduit) monitors the disappearance of the isourea‑ester intermediate (peak 1725 cm⁻¹); a hold step is triggered when the signal falls below 5 % of the initial absorbance. Deviation of the internal temperature above 8 °C during the dosing phase results in a bis‑acylated by‑product (confirmed by HRMS) that reaches 2.8 area‑% and cannot be adequately purged by slurry washing with MTBE alone, requiring a hot‑filtration through a 0.2 µm cartridge at 50 °C to drop below the 0.15 area‑% specification for the crude intermediate. After 12 h age‑time the batch is quenched with 5 vol of water, the slurry filtered on a Nutsche filter‑dryer, washed with water and heptane, and dried under vacuum (50 °C, 10 mbar) to constant loss on drying (≤0.3 %, ASTM E1868). The isolated yield spans 80–88 %, with the bottleneck being the water‑wet cake handling time, which if extended beyond 8 h at ambient temperature promotes amide hydrolysis to the acid (0.6 % h⁻¹ rate constant observed at 22 °C).

During the route scouting for a CRTh2 antagonist candidate, the research group encountered a processing window of ±3 °C for the Boc protection of 5‑aminothiazole‑4‑carboxamide using di‑tert‑butyl dicarbonate in THF/water. At temperatures below 0 °C the reaction stalled at 70 % conversion after 20 h, while above 8 °C rapid decomposition of the Boc‑anhydride generated isobutylene and CO₂, pressurising the reactor to 0.5 bar gauge and causing foaming that overran the 2000 L vessel’s vapour‑disengagement volume. The resolved protocol used a jacketed temperature control with tolerance ±1 °C, and the feed of Boc₂O was split into six equal portions dosed at 15‑min intervals, each followed by a pH adjustment to 8.5–9.0 with 2 N NaOH to scavenge the liberated t‑butanol‑derived acidity.

Moisture Uptake and Packaging Requirements for Long-Term Stability

Dynamic vapour sorption analysis (DVS Intrinsic, SMS Ltd) over a 0–90 % RH cycle at 25 °C shows a 1.8 wt% mass increase at 60 % RH and 4.2 wt% at 80 % RH. The sorption isotherm exhibits hysteresis, indicating formation of a meta‑stable monohydrate that reverts slowly upon desiccation. Material processed in an ISO 14644‑1 Class 8 cleanroom must therefore be dried immediately under nitrogen flow before packaging. The specified packaging configuration, qualified following ASTM D4169‑16 distribution cycle testing, employs a double‑polyethylene liner inside a fibreboard drum, with a molecular sieve desiccant (4A, 100 g per 10 kg of product) and an oxygen absorber sachet. Container closure integrity is verified by helium leak detection (detection limit 6×10⁻⁸ Pa m³ s⁻¹).

Quality control retains samples undergo an annual check for appearance, HPLC purity, and water content; data from 18 batches stored over 36 months at 2–8 °C show no significant linear degradation trend (ANOVA p‑value 0.42 for purity endpoint), confirming the assigned retest period.

When 5-Aminothiazole-4-Carboxamide is Used as a Key Intermediate in Continuous Flow Processes

The moderate solubility of the free amine in non‑protic solvents (approx. 12 g L⁻¹ in DMF, 8 g L⁻¹ in acetonitrile at 25 °C) becomes a limitation in a continuous plug‑flow reactor. To achieve a 0.25 M feed concentration for a subsequent SNAr step, a slurry‑to‑solution system was implemented where the solid is pre‑dissolved in a 50 °C DMF stream using a jacketed, magnetically driven agitated vessel, filtered in‑line through a 60 µm sintered‑metal frit, and fed into a Corning Advanced‑Flow G1 reactor. Below 40 °C the solution is metastable; precipitation of the amine‑HCl salt occurs within the residence‑time module when the chloride counter‑ion is introduced, causing a rapid increase in pressure drop from 0.8 bar to 2.4 bar within 20 min of operation. Mitigation is achieved by incorporating a 10 mol% excess of a hindered organic base (2,6‑lutidine) relative to the amine and installing an ultrasonic probe on the first reactor plate, which reduces particle size to ≤15 µm and prevents channel blockage for runs exceeding 8 h. The productivity achieved, 1.8 kg h⁻¹ of isolated Intermediate‑X, represents a four‑fold improvement over a batch process with identical volumetric productivity per reactor footprint.

During a routine analysis of an R&D batch, an unknown impurity eluting at relative retention time 1.32 (HPLC Method AT‑4‑A) reached 0.21 area‑% after stress at 60 °C in 1 N HCl for 4 h. HRMS and ¹³C NMR identified the species as the ring‑opened thiazoline derivative; its formation indicated that strong acid conditions should be avoided in work‑up and that the pH of aqueous quenches during amide coupling must be maintained above 3.0. This observation was subsequently incorporated into the Process Development Report and triggered the addition of an IPC limit of NMT 0.10 area‑% for this degradant before the crystallisation step.

Key property comparison of three aminothiazole carboxamide regioisomers
Property	5‑Aminothiazole‑4‑carboxamide	2‑Aminothiazole‑4‑carboxamide	2‑Aminothiazole‑5‑carboxamide
CAS RN	454‑91‑1	2153‑18‑0	2153‑19‑1
Melting range (DSC onset, decomp.)	208–212 °C	198–203 °C	210–215 °C
Solubility in DMSO (25 °C, g L⁻¹)	~40	~55	~35
Observed pKₐ (NH₂)	~3.5	~4.1	~3.8
Predominant electrophilic substitution site	C2	C5	C4 (when free); mostly inert
Rate of oxidative dimerisation (AOM, 40 °C/75 % RH, 7 d)	0.7 area‑%	2.4 area‑%	1.9 area‑%
Typical residual solvent after tray drying	DMF < 500 ppm	Ethanol < 200 ppm	Methanol < 300 ppm

Key property comparison of three aminothiazole carboxamide regioisomers

Property

5‑Aminothiazole‑4‑carboxamide

2‑Aminothiazole‑4‑carboxamide

2‑Aminothiazole‑5‑carboxamide

CAS RN

454‑91‑1

2153‑18‑0

2153‑19‑1

Melting range (DSC onset, decomp.)

208–212 °C

198–203 °C

210–215 °C

Solubility in DMSO (25 °C, g L⁻¹)

~40

~55

~35

Observed pKₐ (NH₂)

~3.5

~4.1

~3.8

Predominant electrophilic substitution site

C4 (when free); mostly inert

Rate of oxidative dimerisation (AOM, 40 °C/75 % RH, 7 d)

0.7 area‑%

2.4 area‑%

1.9 area‑%

Typical residual solvent after tray drying

DMF < 500 ppm

Ethanol < 200 ppm

Methanol < 300 ppm

HS Code	578180
Chemical Formula	C4H5N3OS
Molecular Weight	143.167 g/mol
Appearance	Solid
Melting Point	~200 - 205 °C
Solubility In Water	Slightly soluble
Solubility In Organic Solvents	Soluble in some polar organic solvents like DMSO
Stability	Stable under normal conditions, may decompose on heating

Packing	5 - Aminothiazole - 4 - Carboxamide: Packed in 100 - gram bags for secure storage and handling.
Shipping	5 - Aminothiazole - 4 - Carboxamide is shipped with strict adherence to chemical transportation regulations. It's carefully packaged to prevent spills and damage, and transported in containers suitable for its chemical nature, ensuring safe transit.
Storage	5 - Aminothiazole - 4 - Carboxamide should be stored in a cool, dry place. Keep it away from heat sources and direct sunlight, as these can potentially degrade the chemical. Store it in a well - sealed container to prevent moisture absorption and contact with air, which might lead to chemical reactions. Ensure proper labeling for easy identification and to follow safety protocols.

5-Aminothiazole-4-Carboxamide