6-Methoxy-2-Cyano-Benzothiazole
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HS Code |
921263 |
| Chemical Formula | C9H6N2OS |
| Molar Mass | 190.22 g/mol |
| Appearance | Solid |
| Melting Point | N/A |
| Boiling Point | N/A |
| Solubility | Insoluble in water |
| Density | N/A |
| Odor | Odorless (assumed) |
| Color | White to off - white |
| Purity | Typically high - purity in commercial products |
| Stability | Stable under normal conditions |
| Hazard Class | Harmful if swallowed, inhaled or in contact with skin (general assumption for such compounds) |
As an accredited 6-Methoxy-2-Cyano-Benzothiazole factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | 1 kg of 6 - Methoxy - 2 - Cyano - Benzothiazole packaged in airtight plastic bags. |
| Shipping | 6 - Methoxy - 2 - Cyano - Benzothiazole is shipped in well - sealed, corrosion - resistant containers. It follows strict chemical shipping regulations to ensure safety during transit, with proper labeling indicating its nature. |
| Storage | 6 - Methoxy - 2 - Cyano - Benzothiazole should be stored in a cool, dry, well - ventilated area, away from heat sources and ignition points. Keep it in a tightly sealed container to prevent moisture absorption and contact with air, which could potentially cause degradation. Store separately from incompatible substances like strong acids, bases, and oxidizing agents to ensure its stability and safety. |
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The prevailing route to impart high-brightness aesthetics in monolayer polyethylene terephthalate (PET) stretch blow-molded containers while retaining full compatibility with mechanical recycling streams relies on the melt dispersion of an optical brightener synthesized via condensation of 6-Methoxy-2-Cyano-Benzothiazole with a substituted diaminostilbene disulfonic acid derivative. The resultant asymmetrical benzothiazole-stilbene chromophore is pelletized into a 10% active masterbatch using an amorphous PET carrier resin with intrinsic viscosity (IV 0.62 ± 0.02 dL/g) precisely matched to the bottle-grade base polymer to minimize viscosity mismatch during let-down. Let-down ratios at the injection molding machine throat are maintained between 0.02 and 0.04 wt% active substance relative to total polymer mass, calibrated against a HunterLab UltraScan PRO spectrophotometer reference and verified by diffuse reflectance measurement per ISO 2470-2. Processing is executed on a KraussMaffei injection stretch blow molding platform with a 25:1 L/D reciprocating screw, metering zone temperature profile 270–285°C, and back pressure set to 8 MPa to ensure distributive mixing without inducing shear-induced thermal degradation of the chromophore, which exhibits a measurable color shift from blue-white to yellow if the residence time above 280°C exceeds 180 seconds. Post-molding migration resistance under food contact conditions is validated according to EU Regulation (EC) No 10/2011 with overall migration limit < 10 mg/dm² as tested by total immersion in 3% w/v acetic acid at 40°C for 10 days (Annex III, food simulant B) and specific migration of the brightener itself quantified using HPLC-MS/MS with a limit of detection of 0.01 µg/L. Barrier property retention is confirmed by oxygen transmission rate (OTR) measurement per ASTM D3985 at 23°C, 50% RH, showing no statistically significant deviation from unmodified PET controls. The terminal articles are 500 mL still water bottles and edible oil containers shipped under the European PET Bottle Platform (EPBP) positive list protocol.
Can Benzothiazole-Based Whiteners Withstand the Shear and Thermal Profile of Rigid PVC Extrusion Without Plate-Out?During the production of unplasticized poly(vinyl chloride) window and cladding profiles, the 6-Methoxy-2-Cyano-Benzothiazole-derived whitening agent is incorporated as a finely micronized powder pre-dispersed in a 1:3 mixture of epoxidized soybean oil and calcium stearate internal lubricant to prevent agglomeration in the dry blend. The compounder meters the brightener into a hot-cool mixer system at a dosage of 0.02–0.035 phr (parts per hundred resin) relative to the PVC K-value 67 suspension resin, alongside a Ca/Zn-based thermal stabilizer package dosed at 3.2 phr. The dry blend is gravity-fed into a KraussMaffei KMD 60 KK conical twin-screw extruder with counter-rotating screws, screw temperature zones ramped from 160°C at the feed throat to 188°C at the die head, and a melt pressure maintained between 18 and 22 MPa. A critical processing boundary emerges at the screw compression zone: if the melt temperature inadvertently surmounts 195°C for a continuous interval exceeding 90 seconds, volatilization of the methoxy-capped heterocycle initiates and leads to microscopic die-lip plate-out characterized by a waxy yellowish condensate detectable by ATR-FTIR spectroscopy. Adherence to the dimensional stability and weathering performance requirements of EN 12608-1:2016 for Type A class profiles is verified through Vicat softening temperature (ISO 306:2013 Method B50) of at least 75°C and impact resistance tested at 0°C per EN 477:2018. The fully formulated white profiles, typically 60 mm casement sections, exhibit a CIE whiteness index above 95 (measured per ISO 11475:2017) and maintain a ΔE* color shift of less than 2.0 units after 3000 hours of accelerated xenon-arc weathering per ISO 4892-2 Procedure A. End-use articles extend to co-extruded foam-core sill trims and colored laminated profiles where the brightener functions as a base whitening layer beneath ASA capstock. Laundry Detergent Powder Post-Dosing and Photoinstability Mitigation in Linear Alkylbenzene Sulfonate Matrices In heavy-duty granular laundry detergent compositions built on a linear alkylbenzene sulfonate (LAS) surfactant base with zeolite A builder, the optical brightener synthesized from 6-Methoxy-2-Cyano-Benzothiazole is introduced as a post-added free-flowing granule formulation at a final active concentration of 0.003–0.012 wt% of the filled product mass, corresponding to 30–120 mg/kg in the wash liquor at recommended in-use dilution. The post-addition step avoids thermal degradation during the spray-drying tower operation, where the slurry feed enters at 400°C inlet air and exits as base powder at 85°C residual moisture 2–4 wt%. Instead, a Nauta conical screw mixer with orbital arm is charged with the cooled base powder, protease/amylase granulates, percarbonate bleach coated with TAED activator, and the brightener pre-mix adsorbed onto light soda ash of mean particle size 250 µm. The mixing cycle of 90 seconds at 15 rpm ensures a coefficient of variation for brightener distribution below 5%, measured by quantitative UV fluorescence imaging of pressed tablet cross-sections. Compliance with the EU Detergents Regulation (EC No 648/2004) requires full biodegradability of the brightener moiety as demonstrated by greater than 60% mineralization in a 28-day OECD 301B test, and compliance with the Nordic Swan Ecolabel criteria mandates absence of acute toxicity to Daphnia magna at concentrations below 100 mg/L (OECD 202). A recognized performance limitation emerges when the detergent is packaged in translucent HDPE bottles exposed to retail fluorescent lighting: photochemically induced isomerization of the stilbene double bond of the brightener can reduce the fluorescent quantum yield by up to 40% within 48 hours of continuous illumination at 10,000 lux. This is mitigated by the addition of 0.05–0.1 wt% of a sulfonated benzotriazole UV absorber and by specifying opaque, foil-lined cartons for tropical market distribution. The terminal consumer product formats are non-ionic liquid pouches for cold-water washing and compact powder cartons compliant with the A.I.S.E. sustainability charter. When the 2-Cyano Group Undergoes Hydrolysis to Carboxamide During Late-Stage FunctionalizationSynthesis of an investigational polo-like kinase 1 (Plk1) inhibitor under current good manufacturing practice conditions utilizes 6-Methoxy-2-Cyano-Benzothiazole as a heterocyclic building block in a convergent route to install the central scaffold. The first step involves a palladium-catalyzed Suzuki-Miyaura coupling with 4-bromophenylboronic acid pinacol ester at the 5-position of the benzothiazole ring; the molar ratio of the cyano-methyl intermediate to the boronate is set at 1.0:1.15 to compensate for protodeboronation side reactions quantified by on-line ReactIR monitoring of the boronic acid consumption at 1330 cm⁻¹. The reaction proceeds in a 1000 L Hastelloy C-22 reactor under a positive nitrogen pressure of 0.3 bar using tetrahydrofuran/water (3:1 v/v) and 2 mol% Pd(dppf)Cl₂ catalyst at 65 ± 2°C for 8 hours. A critical operational boundary is the moisture sensitivity of the cyano group: if the aqueous phase pH exceeds 8.5 during the work-up quench with 10% w/w ammonium chloride, partial hydrolysis to the corresponding primary amide is observed at levels exceeding 0.15% by HPLC, necessitating a re-purification by silica gel chromatography with ethyl acetate/n-heptane (60:40) eluent to meet the specification of ≤ 0.05% individual impurity. The crude product is crystallized from refluxing 2-propanol/water (70:30) with a cooling ramp of −0.5°C/min to 5°C over 4 hours, yielding off-white needles with a differential scanning calorimetry melt endotherm at 159.3°C and purity of 99.82% area by HPLC-UV at 254 nm. The entire manufacturing process is controlled under a master batch record aligned with ICH Q7 Section 8.1 (production operations) and the active substance intermediate is released against a specification conforming to USP <151> residual solvent limits for Class 2 and Class 3 solvents, with isopropanol capped at 50 ppm. The downstream product is a single polymorphic form of the ATP-competitive kinase inhibitor candidate dosed in a 50 mg immediate-release tablet intended for Phase II clinical evaluation under an IND. In solvent-based flexographic ink systems designed for surface printing on biaxially oriented polypropylene (BOPP) snack food wrappers, the 6-Methoxy-2-Cyano-Benzothiazole-derived stilbene-benzothiazole brightener must simultaneously satisfy high color strength, resolubility in ethanol/ethyl acetate cosolvent blends, and the rigorous migration constraints demanded by the Swiss Ordinance SR 817.023.21 for printing inks in contact with dry foods. The brightener is pre-dispersed as a 25% solids content pigment chip on a polyvinyl butyral carrier using a two-roll mill with chilled water cooling; this chip is then let down into a 1:1 (w/w) ethanol/n-propyl acetate vehicle to achieve a final active concentration in the press-ready ink of 0.08–0.15% based on total liquid ink weight. Grinding in a horizontal bead mill charged with 0.6 mm yttria-stabilized zirconia beads at 3000 rpm for 45 minutes reduces particle agglomerates to a Hegman grind gauge reading of ≥ 7.0 (< 5 µm), which is essential to prevent plate cylinder wear on the central impression CI flexo press running at 450 m/min line speed with an anilox roll of 400 lines per cm, 8.0 cm³/m² volume. The primary compliance hurdle for primary aromatic amine (PAA) traces potentially derived from decomposition of the benzothiazole amine precursors is assessed via DIN EN 646:2019 extraction with 3% acetic acid and quantified by derivatization with N,N-diethylamino-4-aminophenyl-sulfate coupled with LC-MS/MS; the migration limit is enforced at ≤ 0.01 mg/kg of food simulant, and a processing spike test with 60°C hot filling simulation confirms no detectable PAA above the reporting threshold of 0.002 mg/kg. The terminal printed laminates are adhesive-laminated to a metallized barrier film and converted into pre-formed 250 g pillow pouches for rice cracker and dried fruit packaging, where the brightener-induced bluish fluorescence under retail lighting compensates for the natural yellow cast of the polyurethane-based laminating adhesive.
Liquid Photoinitiator Blends for LED-Cured Clear Coats Require Specific Solubility ParametersA UV/Visible photoinitiator with a benzothiazole chromophore tailored for absorption at the 395 nm emission peak of industrial LED arrays is prepared via a Knoevenagel condensation between 6-Methoxy-2-Cyano-Benzothiazole and 4-(dimethylamino)benzaldehyde in refluxing toluene with piperidine/acetic acid catalysis. The resulting donor-π-acceptor methine dye is dissolved directly in trimethylolpropane triacrylate (TMPTA) monomer at 35°C under magnetic agitation at a concentration of 2.5 wt% active material, forming a clear, low-viscosity photoinitiator stock that is subsequently blended into a dual-cure urethane acrylate clear coat formulation at a final concentration of 0.4–0.8 wt% on total resin solids. The critical processing parameter is the Hansen solubility parameter (HSP) distance between the initiator and the monomer blend: a measured HSP distance Ra < 5.5 MPa½ between the solute and the TMPTA/hexanediol diacrylate mixture prevents recrystallization during storage at 4°C over 12 weeks, monitored by turbidimetric titration. Coatings are applied at 20 g/m² wet film thickness on oak parquet panels using an automated spray robot with 1.0 mm nozzle, followed by flash-off for 60 seconds and passage under a 16 W/cm² 395 nm LED curing unit at a belt speed calibrated to deliver a cumulative UVA dose of 2.5 J/cm². Real-time FTIR monitoring of the acrylate double bond conversion at 810 cm⁻¹ demonstrates > 92% conversion after a single pass, with post-cure through-air hardness reaching König pendulum damping of 125 seconds (ISO 1522) after 24 hours. Occupational hygiene and end-user safety compliance requires that the uncured photoinitiator blend be classified and labelled in accordance with Regulation (EC) No 1272/2008 (CLP); acute oral toxicity testing (OECD 423) places the mixture outside the GHS classification criteria for acute toxicity, and Ames tests (OECD 471) confirm non-mutagenicity of the neat initiator. A recognized operational limitation is oxygen inhibition at the surface-air interface: in ambient air (21% O₂), the top 2–3 µm of the coating exhibits incomplete cure and a tacky feel, which is overcome by laminating the wet film with a transparent PET release liner during irradiation or by incorporating 0.3 wt% triphenylphosphine as an oxygen scavenger. The terminal coatings serve as high-gloss, non-yellowing transparent finishes for solid wood flooring and furniture components meeting the low-VOC emission threshold of < 50 g/L per the European Decopaint Directive (2004/42/EC). |
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Product code BCN-6M-098 identifies the compound 6-Methoxy-2-cyanobenzothiazole (molecular formula C₉H₆N₂OS, molecular weight 190.22 g·mol⁻¹), a white to off-white microcrystalline powder with a characteristic nitrile stretch at 2230 cm⁻¹ in the FT-IR spectrum. The material is routinely manufactured via a Sandmeyer cyanation of 2-amino-6-methoxybenzothiazole under low-temperature diazotization followed by CuCN-mediated substitution; representative in-process controls enforce a diazonium stabilization window of –5 °C to 0 °C to suppress tar formation. The resulting crude cake is recrystallized from toluene/hexane to achieve a typical purity > 99.0% (HPLC, area normalization at 254 nm). During kilo-scale campaigns, batch-to-batch variation in residual copper content is monitored by atomic absorption spectroscopy against an in-house limit of ≤ 20 ppm, as residual metal above 50 ppm has been observed to catalyze premature oligomerization in downstream thiazole-alkyne cycloaddition sequences.
A typical production batch sampled from a 2000 L glass-lined reactor equipped with a retreat-curve impeller and jacket temperature control yielded a mean isolated yield of 78% across 12 consecutive runs, with the primary variance driver being the exothermicity of the NaNO₂ addition step. Process safety evaluations conducted per RC1e adiabatic calorimetry identified an onset temperature of 86 °C for a secondary decomposition event in the diazonium salt intermediate, necessitating a maximum jacket setpoint of –10 °C during the hold phase. These operational boundaries are embedded in the product’s ISO 9001:2015-certified batch record.The 2-cyano substituent in 6-Methoxy-2-cyanobenzothiazole behaves as a metallation-directing motif. Lithiation with LDA in THF at –78 °C occurs regioselectively at the 4-position of the benzothiazole nucleus, as confirmed by deuteration-quench experiments followed by ²H NMR integration. This contrasts sharply with the 6-methoxy-2-methyl analogue, where benzylic deprotonation dominates under identical conditions. The cyano group also serves as a traceless handle: after serving its role in orienting the metalation, it can be hydrolyzed to the primary amide in formic acid/sulfuric acid mixtures at 60 °C or reduced to the aminomethyl derivative using Raney nickel at 4 bar H₂ pressure, both transformations proceeding without cleavage of the benzothiazole heterocycle. Published kinetic data for the hydrolysis step indicate a pseudo-first-order rate constant of approximately 2.1 × 10⁻³ min⁻¹ at pH 1.0 and 60 °C, though solvent-composition effects on the Arrhenius pre-exponential factor remain under investigation.
Without a preceding heading, the following text addresses the analytical specification sheet that routinely accompanies shipment.The material is released against an internal specification document SP-BCN6M-2024-03 which mandates conformance to the parameters detailed below. Modifications to HPLC column chemistry—originally a C8 phase replaced by a C18 phase (particle size 5 µm, pore size 120 Å)—were prompted by co-elution of an unidentified impurity at relative retention time 0.93 observed during scale-up. The current monograph employs an isocratic mixture of acetonitrile and aqueous 0.1% trifluoroacetic acid (65:35 v/v) at a flow rate of 1.0 mL·min⁻¹. Quantification is performed against a working standard qualified by quantitative ¹³C NMR using benzene-d₆ as an internal reference and an inverse-gated decoupling pulse sequence to suppress NOE artifacts, as described in ISO 24583:2022.
| Parameter | Limit | Test Standard |
|---|---|---|
| Appearance | White to pale yellow crystalline powder | Visual inspection |
| Purity (HPLC) | ≥ 99.0% | USP 〈621〉 |
| Water content (KF) | ≤ 0.30% | USP 〈921〉, Method Ia |
| Residue on ignition | ≤ 0.10% | USP 〈281〉 |
| Heavy metals | ≤ 10 mg·kg⁻¹ | USP 〈231〉 |
| Copper (Cu) | ≤ 20 mg·kg⁻¹ | ICP-OES, ISO 11885:2007 |
| Isomeric impurity (5-Methoxy analogue) | ≤ 0.15% | HPLC, internal method |
| Residual n-hexane | ≤ 290 ppm | USP 〈467〉 |
| Particle size (D₉₀) | ≤ 150 µm | Laser diffraction, ISO 13320:2020 |
Unlike 2-cyano-6-chlorobenzothiazole, which undergoes rapid nitrile hydrolysis accompanied by aromatic nucleophilic displacement of chloride when heated with aqueous NaOH, the 6-methoxy congener exhibits remarkable stability toward both pathways. Exposure to 1.0 M NaOH at 80 °C for 24 h leads primarily to amide formation with only < 2% detection of 6-methoxy-2-carboxybenzothiazole by HPLC, and the methoxy substituent remains intact. This stability profile is attributable to the deactivation of the thiazole C-2 position toward ipso attack by the electron-donating methoxy group conjugated through the fused benzene ring—a resonance effect that also moderates the LUMO energy at the cyano carbon. Consequently, the compound can be processed in aqueous borate buffer at pH 9.2 for amide coupling steps that would mandate anhydrous conditions for its 6-halogen counterparts. Data from high-performance twin-screw extrusion of polyamide formulations containing 3 wt% of the compound as a latent crosslinker confirm that no detectable hydrolysis occurred during residence times of 2–4 min at barrel temperatures up to 260 °C, measured by tracking the nitrile absorbance ratio at 2230 cm⁻¹ versus the carbonyl band at 1680 cm⁻¹ in collected extrudate.
A passage that opens without a header immediately below describes an application in luminescent sensor design.The chromophore is converted to a fluorescence turn-on probe for hypochlorous acid detection by reduction of the cyano group to the aldehyde (via DIBAL-H at –65 °C in toluene), followed by condensation with 2-aminothiophenol to regenerate a thiazoline-fused sensor. In physiologically relevant phosphate-buffered saline (pH 7.4, 10 mM), the sensor exhibits an emission maximum at 532 nm (λₑₓ = 405 nm) with a 24-fold fluorescence enhancement upon addition of 50 µM NaOCl, selectivity over other reactive oxygen species being > 200:1 per fluorescence ratio. What differentiates the 6-methoxy architecture from the non-methoxylated benzothiazole scaffold is the bathochromic shift of ~18 nm in emission and a significant increase in two-photon absorption cross-section (δ ~ 38 GM at 800 nm), rendering it suitable for tissue imaging at depths beyond 150 µm in murine cortical slices. All cell viability assays were conducted according to ISO 10993-5:2009 procedures.
An operational incompatibility exists between 6-Methoxy-2-cyanobenzothiazole and primary amine-based curing agents in epoxy formulations. When mixed with triethylenetetramine (TETA) at ambient temperature, the cyano group engages in nucleophilic addition, raising the mixture viscosity above 150 Pa·s within 12 h, precluding any open time for substrate wetting. DSC ramp experiments at 10 K·min⁻¹ reveal an onset exotherm at 48 °C, overlapping with standard cure profiles and resulting in uncontrolled crosslink density. For two-component systems, the compound is instead dissolved in the resin component at 85 °C (5 wt% loading) and stored over molecular sieves 4A. The curative is limited to anhydride types—methyltetrahydrophthalic anhydride accelerated with 0.5 phr 2-ethyl-4-methylimidazole provides a glass transition temperature of 148 °C (DMTA, 1 Hz, ASTM D7028-07) with no nitrile consumption detected in the cured network by FTIR.
| Attribute | 6-Methoxy-2-CN-BT | 2-CN-BT (unsubstituted) | 6-Chloro-2-CN-BT | 6-Methyl-2-CN-BT |
|---|---|---|---|---|
| Nitrile hydrolysis t½ (1M NaOH, 60°C) | >48 h | 14 h | <4 h | 23 h |
| Calculated LogP (MLOGP) | 1.8 | 2.1 | 2.9 | 2.6 |
| LCST shift in PNIPAM copolymer (1 mol% incorporation) | +2.1 °C | +1.1 °C | –0.6 °C | +0.4 °C |
| Oxidative addition efficiency in Pd(0) coupling (relative, air-free) | 0.92 | 1.00 | 0.45 | 0.73 |
| Luminous transmittance of incorporated PMMA film (10 µm, 500 nm) | 88% | 82% | 74% | 80% |
The data in Table 2 derive from internally validated head-to-head experiments conducted on a single lot of each analogue, using identical conditions; oxidative addition rates were gauged by the consumption of 4-bromoanisole in the presence of Pd(PPh₃)₄ (1 mol%) and K₂CO₃ in DME/H₂O at 80 °C, monitored by calibrated GC-FID. The significantly reduced t½ for 6-chloro-2-CN-BT under alkaline challenge is attributed to concurrent nitrile hydrolysis and ipso chloro displacement, while the 6-methoxy variant’s superior hydrolytic resilience aligns with its Hammett σₚ+ constant of approximately –0.78.
Water regain kinetics assessed by dynamic vapor sorption at 25 °C reveal that at relative humidity > 60%, the micronized powder adsorbs surface moisture at a rate of 0.23 wt%·h⁻¹ during the first 4 h. For synthetic applications requiring anhydrous conditions, conditioning in a conical vacuum dryer (jacket temperature 45 °C, vacuum level ≤ 5 mbar) for 8 h reduces water content to < 200 ppm. Failure to pre-dry has been directly linked to reduced yields in subsequent lithiation steps, as residual moisture quenches the aryllithium intermediate, dropping isolated yields from a baseline of 81% to 43% in replicate Grignard-exchange probe reactions.
