1,3-Thiazole-2-Carbonitrile

In the synthesis of 2-cyano-N-(2,4-dichlorophenyl)thiazole-5-carboxamide, an active ingredient deployed against Botrytis cinerea at field rates of 150–300 g a.i./ha, 1,3-thiazole-2-carbonitrile is introduced as the core heterocycle that supplies both the nitrile and the carboxylic acid precursor. The operation begins by charging 1.0 eq. of the nitrile (assay ≥99.0%, moisture ≤0.3%) into a glass-lined reactor equipped with a retreat-blade impeller and a jacket fed with brine at −5 °C. Deionized water equal to 8.0 vol per weight of substrate is added, followed by slow dosing of aqueous sodium hydroxide (30% w/w, 1.2 eq.) over 45–60 min. The hydrolysis exotherm must be clamped below 25 °C; a spike above 30 °C cleaves the thiazole ring, generating mercaptoacetamide impurities that elute at 4.2 min on a C18 column (150×4.6 mm, 5 μm) with UV detection at 254 nm. After hydrolysis, the resulting sodium 2-cyanothiazole-5-carboxylate is acidified with 37% HCl to pH 2.0–2.5, filtered, and washed to conductivity <50 μS/cm. The wet cake is taken up in toluene, azeotropically dried to a Karl Fischer endpoint of <0.1% water, and then treated with thionyl chloride (1.15 eq.) under catalytic DMF (0.5 mol%) at reflux until gas evolution ceases. The resulting acyl chloride is coupled in the same vessel with 2,4-dichloroaniline (1.03 eq.) in the presence of triethylamine (1.2 eq.) at 0–5 °C, yielding the target carboxamide after solvent swap to methanol and crystallization. The crude product is recrystallized from isopropanol/water (7:3 v/v) to achieve a purity of >98.5% with individual unspecified impurities capped at 0.15% as per a monograph modeled on CIPAC MT 46.3. Downstream, the technical material is micronized in a spiral jet mill to a particle size D₅₀ of 3–5 μm and formulated as a 500 g/L suspension concentrate. The SC must pass a wet sieve retention test (CIPAC MT 185, 75 μm sieve, residue ≤0.5%) and a pourability test (CIPAC MT 148) to qualify for tank-mix compatibility. For exporters, the substance is registered under REACH as a non-isolated intermediate transported under strictly controlled conditions per Article 18(4), with a recommended tonnage band of 10–100 t/a triggering a full chemical safety report. Storage in the original PE-lined fibre drum at ≤30 °C and relative humidity <55% is mandatory to prevent ring-opening hydrolysis; opened containers must be re-blanketed with nitrogen and consumed within 14 days.

What quality-by-design parameters are critical when integrating the nitrile into an EGFR T790M inhibitor scaffold?

For a clinical-stage irreversible inhibitor targeting the T790M gatekeeper mutation in non-small cell lung cancer, 1,3-thiazole-2-carbonitrile is elaborated into a 2-cyano-4-methylthiazole-5-carboxylate intermediate that places the nitrile at a precise distance from the Michael acceptor warhead. The route employs a Hantzsch-type cyclocondensation between thiourea and ethyl 2-chloroacetoacetate to build the thiazole ring, followed by regiospecific cyanation at the 2-position using zinc cyanide (0.55 eq.), zinc powder (0.06 eq.), and PdCl₂(dppf)·CH₂Cl₂ (0.5 mol%) in a degassed mixture of N,N-dimethylacetamide and water (9:1 v/v) heated to 85 °C for 6 h. The process is designed within an ICH Q8(R2) quality-by-design framework using three-factor DoE: reaction temperature (80–90 °C), stoichiometric excess of Zn(CN)₂ (0.50–0.60 eq.), and agitation rate (300–500 rpm). The proven acceptable range confirms that temperatures exceeding 92 °C promote des-cyano protodeiodination, raising the level of the 2-H des-cyano impurity above the limit of 0.10%, while falling below 78 °C stalls conversion at an unacceptable 82%. The crude cyano ester is hydrolyzed with lithium hydroxide (2.0 eq.) in THF/water (3:1) at 22–25 °C for 16 h, giving the free acid which is isolated by pH adjustment to 5.5 with aqueous citric acid and extracted into ethyl acetate. All unit operations from the amide coupling step onward are conducted in an ISO 8 cleanroom with HEPA-filtered air and on equipment fabricated from 316L stainless steel passivated per ASTM A967/A967M-17 nitric acid treatment. The final API batch must satisfy ICH Q3D(R2) elemental impurity thresholds: Pd ≤10 μg/g, Zn ≤1300 μg/g (oral PDE), and Ni ≤60 μg/g. Residual solvents are controlled to ICH Q3C(R8) class 2 limits, with DMAc specified at ≤1090 ppm and THF at ≤720 ppm. The drug substance is micronized using a pin mill under liquid nitrogen cooling to achieve a particle size D₉₀ of ≤10 μm for direct compression into tablets; blend uniformity is verified by near-infrared spectroscopy against a validated model built with the pure API spectrum. Manufacturing logistics require shipment of the thiazole-2-carbonitrile in UN-approved 4G fibreboard boxes with inner PTFE liners, labelled with GHS hazard code H302+H312+H332, and a documented shelf life of 24 months from the date of analysis when stored at 2–8 °C under argon.

A range of heterocyclic azo disperse dyes suitable for high-temperature exhaust dyeing of polyester and its blends with elastane is constructed using 1,3-thiazole-2-carbonitrile as the electron-deficient diazo component. In a typical preparation of C.I. Disperse Red 338-type chromophores, a diazonium salt is generated by suspending 1.0 eq. of the thiazole nitrile in a mixture of phosphoric acid (85%), acetic acid, and propionic acid at 0–5 °C, then adding nitrosylsulfuric acid (40% w/w in sulfuric acid, 1.05 eq.) dropwise while maintaining the temperature below 8 °C. The diazo solution is coupled into a chilled slurry of N-ethyl-N-(2-cyanoethyl)aniline (1.02 eq.) dispersed in water with a nonionic surfactant (fatty alcohol ethoxylate, HLB 14) at pH 3.0–3.5 and 0–3 °C. After coupling, the pH is raised to 5.5 with sodium acetate, the slurry is heated to 85 °C, and the crystalline dye is isolated on a filter press, washed until the conductivity of the filtrate drops below 200 μS/cm, and dried in a vacuum double-cone dryer at 80 °C and 20 mbar to a residual moisture of ≤0.5%. The dye exhibits λ_max at 510 nm in acetone with a molar extinction coefficient of 4.8×10⁴ L·mol⁻¹·cm⁻¹. For commercial delivery, the presscake is standardised with a lignosulfonate dispersant to a strength of 200% versus a reference standard and assessed for dispersion stability according to AATCC 146, filtration value (≤2.0 s/100 mL) as per EN ISO 787-7, and high-temperature dispersion stability at 130 °C for 60 min. Shade reproducibility on polyester is confirmed by CIELAB colour difference ΔE_CMC ≤0.5 units against a certified reference under D65 illuminant. The finished dye must comply with the restricted substance list of OEKO-TEX^® Standard 100 Annex 6 for aromatic amines derived from reductive cleavage, ensuring the 2-cyanothiazole moiety does not release any listed carcinogenic amine. Packaging in 25 kg fibre drums with an inner EVA liner is standard; the product is classified as non-dangerous under IMDG Code but requires a safety data sheet aligned with Regulation (EC) No 1907/2006.

Acidizing Corrosion Inhibitor Packages for High-Sour Gas Wells

Condensation of 1,3-thiazole-2-carbonitrile with diethylenetriamine at a molar ratio of 1.0:1.8 in the presence of p-toluenesulfonic acid (0.5 wt% relative to total charge) at 140–145 °C for 8 h yields an aminoethylimidazoline-thiazole hybrid that functions as a high-temperature filming inhibitor in stimulating dolomite and sandstone formations with 15% HCl. The reaction is conducted in a Hastelloy C-276 reactor under a slow nitrogen sweep to remove evolved ammonia; the progress is tracked by monitoring the nitrile absorbance at 2230 cm⁻¹ via inline ATR-FTIR. When the residual nitrile content drops below 0.5 wt%, the melt is cooled to 80 °C and formulated by adding propargyl alcohol (8.0 wt%), cinnamaldehyde (5.0 wt%), and isopropanol to yield a concentrate with an activity of 65%. For qualification of the inhibitor, weight-loss coupons of N-80 carbon steel (API 5CT grade, surface finish 600 grit) are immersed in 15% HCl containing the inhibitor at 0.2 vol%, 0.5 vol%, and 1.0 vol% at 90 °C for 6 h under a simulated bottomhole pressure of 10.3 MPa with H₂S partial pressure at 0.5 MPa, following NACE Standard TM0196-2016. Corrosion rates determined by mass loss are tabulated as a function of inhibitor loading, and the protection efficiency must exceed 99.0% at 1.0 vol% and 98.5% at 0.5 vol% to meet operator specifications. Pitting tendency is evaluated by scanning electron microscopy; no pit deeper than 20 μm is permissible on any coupon. Field blending units meter the concentrate into the acid pump truck at a ratio of 3–5 L/m³ of live acid, and the blended fluid is sheared through a jet mixer before entering the coiled tubing. The inhibitor carries a Globally Harmonized System classification of Skin Corrosion Category 1B and Aquatic Chronic 3, necessitating UN 3265 packaging in 200 L epoxy-phenolic-lined steel drums. A certificate of analysis for each batch must report the thiazole-2-carbonitrile content of the raw material (GC purity ≥99.0%), amine value of the imidazoline intermediate (420–450 mg KOH/g), and the inhibitor’s performance in the NACE static autoclave test against the specified threshold.

A table summarising the weight-loss corrosion rates measured at three inhibitor dose levels against the untreated blank is provided for technical reference.

When high-temperature nylon requires a thiazole-dicarboxylic acid monomer

1,3-Thiazole-2-carbonitrile is converted to thiazole-2,5-dicarboxylic acid through a two-step sequence beginning with alkaline hydrolysis to the 2-carboxylic acid, followed by cobalt/manganese-catalysed aerobic oxidation of the methyl substituent at the 5-position (when starting from the 5-methyl analogue) or direct ammoxidation of a 5-methyl precursor. The resulting diacid, after purification by re-slurry in boiling water to remove residual metal ions to below 50 ppm total heavy metals, is polymerised with hexamethylenediamine in water as solvent, forming a nylon salt at pH 7.6–7.8. The salt is concentrated to 65% solids and fed into a continuous polycondensation reactor consisting of a pre-polymeriser at 240 °C/1.7 MPa followed by a finisher operating at 280 °C under vacuum of 0.5 kPa. The polymer exhibits a glass transition temperature elevated by 14 °C relative to PA6T/66 copolyamide of equivalent aliphatic content, as measured by DSC per ISO 11357-2:2020 at a scan rate of 20 K/min. Tensile test bars injection-moulded in a 100-ton clamp-force machine with a melt temperature of 305 °C and mould temperature of 130 °C yield a tensile strength of 92 MPa (ISO 527-2, type 1A specimen, 5 mm/min) and a notched Izod impact of 6.8 kJ/m² (ISO 180/A). The material passes a UL 94 vertical burn test at 0.8 mm thickness with a V-0 rating, making it suitable for insulating components in e-mobility traction battery modules. The nitrile monomer must be stored under nitrogen with a moisture content below 200 ppm, as water ingress above 500 ppm initiates partial hydrolysis that shifts the stoichiometry of the salt and drops the inherent viscosity below the target of 0.85 dL/g. Shipping in 500 kg supersacks with an aluminium barrier layer is standard for export.

The nitrile functionality opens routes to parallel library synthesis of privileged fragments

In early-stage drug discovery, 1,3-thiazole-2-carbonitrile is routinely used as a synthetic handle in the construction of fused [1,3]thiazolo[4,5-d]pyrimidine and thiazole-triazole fragment libraries via copper-catalysed azide-alkyne cycloaddition and nucleophilic displacement of the nitrile with hydrazine or hydroxylamine. A representative parallel synthesis protocol performed on a 24-position MiniBlock^® synthesizer charges each reactor with 0.20 mmol of the nitrile, sodium azide (0.24 mmol), copper(I) iodide (0.02 mmol), and zinc powder (0.06 mmol) in a mixed solvent of DMF/n-butanol (1:1). The array is sealed and heated to 120 °C under microwave irradiation for 20 min with a maximum power of 150 W, achieving conversion of >>95% to the corresponding tetrazole as monitored by LCMS at 215 nm. After filtration through a Celite pad and solvent evaporation in a Genevac HT-24, the crude tetrazoles are subjected to a second diversification step with a set of alkyl halides (each 0.22 mmol) and potassium carbonate (0.30 mmol) in DMF at 60 °C for 4 h. The products are purified by mass-directed preparative HPLC using an acidic modifier (formic acid 0.1%), and the purity of each target compound is verified to be ≥95% by ELSD and UV. For commercial supply to CRO laboratories, the chemical is offered in vials pre-weighed to exact amounts (e.g., 100 mg, 250 mg, 1 g) under an argon atmosphere with a septum cap, accompanied by a certificate of analysis reporting 1H NMR (Bruker 400 MHz, DMSO-d6, δ values assigned for H-4, H-5), FTIR (KBr disc, ν_C≡N at 2232±2 cm⁻¹), and HPLC purity (99.5% at 210 nm). The material is classed as non-GHS for research quantities below 2 kg per shipment but must be accompanied by a safety data sheet highlighting that the nitrile can release hydrogen cyanide upon combustion in an open flame, requiring storage in a flammables cabinet rated per NFPA 30 Class 3B. Order codes typically reference the CAS number 4100-12-3 and batch-specific retest date set at 18 months from packaging when kept at −20 °C in a moisture-free environment.