4,5-Dimethylthiazole
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HS Code |
807600 |
| Chemical Formula | C5H7NS |
| Molar Mass | 113.18 g/mol |
As an accredited 4,5-Dimethylthiazole factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | 500g of 4,5 - Dimethylthiazole packaged in a sealed, chemical - resistant bottle. |
| Shipping | 4,5 - Dimethylthiazole is shipped in sealed, corrosion - resistant containers. It's handled with care to prevent spills, following strict regulations due to its chemical nature, and transported via approved carriers. |
| Storage | 4,5 - Dimethylthiazole should be stored in a cool, dry, well - ventilated area away from sources of ignition and heat. Keep it in a tightly - sealed container to prevent vapor leakage. Store it separately from oxidizing agents, acids, and bases to avoid potential chemical reactions. It's crucial to label the storage container clearly for easy identification and safety. |
In roasted coffee flavor architecture, 4,5-dimethylthiazole operates as a critical bridge between the caramelized sugar backbone and the smoky-sulfurous top notes generated during first-crack roasting. The compound’s odor threshold in water is reported at approximately 0.5–2 ppb, which places it among the most sensorially potent thiazoles used in beverage flavorings. In commercial soluble coffee powder manufacturing, the compound is introduced as part of a compounded liquid flavor at a concentration of 0.05–0.2% (w/w) in the flavor base, which is then dosed into the dry coffee solids at a rate that yields a final cup-level concentration of 0.1–0.5 ppm in the reconstituted beverage. Compliance with FDA 21 CFR 172.515 (synthetic flavoring substances and adjuvants) and FEMA GRAS 3274 is mandatory, with the European Flavourings Regulation EC 1334/2008 and its Union List entry FL 15.075 additionally defining purity parameters of not less than 97% assay by GC. The processing pathway during instant coffee manufacture involves plating the thermally sensitive flavor emulsion onto partially cooled, drum-dried coffee solids at a surface temperature not exceeding 35°C to minimize volatilization losses; facilities equipped with sealed, low-shear ribbon blenders operating at 20–30 rpm report batch-to-batch aroma retention variability below ±5% relative standard deviation. Terminal products include single-serve instant coffee sticks, ready-to-drink canned coffee, and coffee-flavored milk powders, all of which demand the distinctive roasted-nutty and slightly earthy character that 4,5-dimethylthiazole sustains through retorting or UHT processing.What accounts for the lingering roast note in cocoa-based confectionery subjected to prolonged conching?The persistence of roasted character in dark chocolate and cocoa-derived compound coatings is frequently attributable to the non-volatile yet thermally regenerative behavior of 4,5-dimethylthiazole when bound within the cocoa butter continuous phase. During standard roller refining at 40–55°C and subsequent conching cycles lasting 24–72 hours, many pyrazine-based roast markers dissipate, yet this thiazole demonstrates a retention coefficient exceeding 0.85 in mass balance trials conducted on pilot-scale longitudinal conches equipped with in-line SPME-GC monitoring. In molded chocolate bars and enrobed nut clusters, the recommended addition level of the neat compound into the flavor premix is 0.01–0.05% relative to the total fat phase, which translates to a finished product concentration of approximately 2–8 ppm. The applicable regulatory framework encompasses JECFA 1055 (with an ADI of 0–0.5 mg/kg bw) and the IOFI Global Reference List, while halal and kosher certification for the carrier solvents is verified against MUI HAS 23000 and OU standards respectively. Manufacturing integration proceeds via a multi-step dispersion protocol: the crystalline thiazole is first dissolved in propylene glycol at 50°C under nitrogen blanketing to suppress oxidative dimerization, then metered into the liquid chocolate mass at the thin-film disperser inlet immediately upstream of the two-stage scraped-surface tempering unit. Finished formats include 70% cocoa single-origin bars, praline fillings with extended shelf-life stability at 18–22°C, and cocoa-dusted truffle shells, where the compound masks the waxy mouthfeel of cocoa butter substitutes without contributing bitterness at the upper use limit.The application of 4,5-dimethylthiazole in dry-roasted and oil-roasted nut processing leverages its capacity to amplify the Maillard-derived pyrazine matrix without introducing the burnt-phenol off-notes associated with excessive 2-acetylthiazole. Typical roasting regimes for peanut, hazelnut, and almond varieties employ drum roasters with inlet air temperatures of 160–190°C and residence times of 8–15 minutes, during which endogenous thiazoles are generated at levels often insufficient to meet the desired flavor intensity after salt-coating and lipid oxidation masking. Supplementation is accomplished via a powdered encapsulated flavor added at 0.2–0.5% by weight of the seasoned nut mass in a rotating coating pan, corresponding to an active 4,5-dimethylthiazole concentration of 5–15 ppm in the final snack product. The flavor carrier matrix — typically a blend of maltodextrin DE 10–15, gum arabic, and silicon dioxide at <1% — is spray-dried using a co-current tower configuration with an inlet temperature of 180±5°C and outlet of 85±3°C, parameters proven to retain over 92% of the core aroma volatiles in glassy-state encapsulates with a Tg above 45°C. Regulatory adherence mandates compliance with EC 1334/2008 Annex II and 21 CFR 182.60 for the finished snack category, alongside allergen cross-contact verification per FALCPA when processing on shared lines. Downstream products span honey-roasted peanuts, sriracha-coated almonds, and southern-style fried peanut snacks where the thiazole bridges the gap between roast nuttiness and the savory seasoning top-note.When decoupled from trimethylthiazole, how does the dimethyl homologue sharpen savory meat bouillon profiles?In thermally processed meat flavorings such as bouillon cubes, retort-stable broths, and extrusion-cooked pet food palatants, 4,5-dimethylthiazole delivers a well-defined roasted-meat, slightly nutty character that resists degradation during extended holding at 90–121°C in aqueous media. The compound proves particularly effective in formulations where 2,4,5-trimethylthiazole concentrations exceed 3 ppm and begin to impart an undesirable boiled-liver note; partial replacement with 4,5-dimethylthiazole at a 1:1 to 1:1.5 ratio suppresses the organoleptic defect without reducing the total thiazole MUNs (measurement of umami-enhancing nuance). Addition levels in compound savory flavors range from 0.05–0.3% in the liquid seasoning base, yielding a ready-to-consume broth concentration of 0.5–2.0 ppm. Compliance obligations extend to 21 CFR 172.515 and the FEMA GRAS 3274 listing, with EFSA FEEDAP evaluation data required for pet food applications destined for EU markets where the additive is registered under functional group 2b (sensory additives). Production-line integration typically involves pre-emulsifying the thiazole in a heated suspension of mono- and diglycerides (E471) at 60°C, followed by homogenization at 150–200 bar in a two-stage high-pressure homogenizer prior to blending into the hot-process liquid stock base. In extruded pet treat manufacture, the emulsion is injected at the preconditioner inlet of a twin-screw extruder with an L/D ratio of 40:1, wherein the barrel temperature profile rises from 40°C at the feed zone to 135°C at the die plate; post-extrusion loss of the aroma compound remains below 8% when the specific mechanical energy input is constrained to 120–140 Wh/kg. End categories include chicken-flavored instant noodle sachets, beef consommé tablets, and air-dried dog kibble toppers, where the 4,5-dimethylthiazole signature persists through rehydration or microwave finishing.Caramelized Sugar Matrix Interactions and Toasted Bread Crust ApplicationsWithin the heterogeneous structure of baked cereal goods, 4,5-dimethylthiazole interacts synergistically with 2-acetyl-1-pyrroline and 4-hydroxy-2,5-dimethyl-3(2H)-furanone, forming a tri-component roast complex that remains recognizable even after six-month ambient storage at 25°C/60% RH in metallized multi-layer film packaging. In sliced white pan bread and whole-grain artisan loaves manufactured via the sponge-and-dough process, the flavor premix containing the thiazole at 0.1–0.5% in ethanol is sprayed onto the hot crust surface within 60 seconds of oven exit, when the crust temperature is still above 80°C, exploiting rapid evaporative cooling to fix the aroma without thermal destruction. The active compound level in the finished bread is maintained at 1–4 ppm on a dry-weight basis, well below the sensory saturation point. Governing standards include FDA 21 CFR 170.3(o)(28) for bread and cereal products, the GRAS Notification requirements under 21 CFR 170 Subpart E, and Australian NZ Code Standard 1.3.4 for processing aid residues. In high-speed commercial bakeries equipped with tunnel ovens and integrated spray booths, a closed-loop atomization system using twin-fluid nozzles with droplet Sauter mean diameter 35–50 µm delivers uniform deposition at line speeds up to 30 m/min. The process window is narrow: below 70°C crust surface temperature, ethanol evaporation is too slow and causes starch surface solubilization that leads to pale, sticky patches; above 95°C, the aroma compound loss exceeds 15% due to steam stripping. Finished goods carrying the compound include brioche rolls with a butter-roasted character, corn tortilla chips with toasted-corn intensity, and extruded breakfast cereals with a browned grain note that survives the coating drum’s hot syrup application.
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4,5-Dimethylthiazole (CAS 3581-89-3, FEMA 3274, JECFA 1033) is a heterocyclic aroma compound belonging to the thiazole class. Its molecular formula is C5H7NS, with a molar mass of 113.18 g/mol. Commercial availability spans food-grade material (minimum purity 98.0% by GC) and a pharmaceutical intermediate grade exceeding 99.0%. Product codes such as 4,5-DMT-98FG denote the food-compliant grade; custom specifications are supplied under agreed quality agreements. Table 1 lists the standard release parameters for the food-grade product.
| Parameter | Specification | Test Method |
|---|---|---|
| Assay (anhydrous basis) | ≥98.0% | GC-FID, FCC Method |
| Water content | ≤0.1% | Karl Fischer, ISO 760:1978 |
| Refractive index nD20 | 1.510–1.514 | ASTM D1218-21 |
| Density at 20°C | 1.065–1.075 g/mL | ASTM D4052-22 |
| Appearance | Colorless to pale yellow liquid | Visual, APHA ≤50 |
| Heavy metals (as Pb) | ≤5 mg/kg | ICP-MS, USP <233> |
Industrial synthesis of 4,5-dimethylthiazole via Hantzsch cyclization of 3-chloro-2-butanone with thioformamide, generated in situ from formamide and phosphorus pentasulfide, demands rigorous thermal management. In a 5,000 L glass-lined batch reactor (height‑to‑diameter ratio 1.6:1), the addition of 3-chloro-2-butanone to a thioformamide slurry maintained at −5 to 0°C suppresses isomerization pathways that would produce 2,4-dimethylthiazole. The reaction exotherm, measured by differential scanning calorimetry at approximately −110 J/g, requires a jacket cooling capacity of 300 kW instantaneous heat removal. Agitation with a pitched-blade turbine at 85 rpm disperses the P2S5 particulates, while the pH is held at 4.5–5.0 through a buffered thioformamide slurry. Liberated H2S is directed to a scrubber charged with 15% NaOH solution; electrochemical sensors at the vent maintain free H2S concentration at ≤1 ppm. Thermal hazard evaluation by accelerating rate calorimetry (ARC) identifies a self‑heating onset at 85°C for the crude mass post‑solvent strip, imposing a mandatory distillation bottoms temperature ceiling of 70°C with immediate water quench. Distillation under 50 mbar using a structured packing column of 15 theoretical plates (overhead temperature 82°C) isolates 4,5-dimethylthiazole with a purity of 98.5% (GC) and a typical overall yield of 68–72% relative to 3-chloro-2-butanone. Batch‑to‑batch chromaticity variation is controlled within 10 Hazen units (APHA) through post‑distillation treatment with activated carbon.
The three dimethylthiazole isomers share a C5H7NS core but differ in methyl group placement, resulting in distinct organoleptic profiles. 4,5-Dimethylthiazole delivers a nutty, roasted‑cereal character with an odor detection threshold of 2.5 μg/L in water. The 2,4-isomer imparts a green, nutty nuance at a lower threshold of 1 μg/L, while the 2,5-isomer is responsible for a meaty, sulfurous impact with a threshold of approximately 5 μg/L. These differences govern application strategy in compounded flavors. Table 2 summarizes key physical and sensory properties.
| Isomer | CAS Number | FEMA | Boiling Point (°C) | Odor Description | Odor Threshold (μg/L, water) |
|---|---|---|---|---|---|
| 2,4-Dimethylthiazole | 541-58-2 | 3272 | 144–145 | Green, nutty | 1 |
| 2,5-Dimethylthiazole | 4544-92-5 | 3273 | 150–151 | Meaty, roasted | 5 |
| 4,5-Dimethylthiazole | 3581-89-3 | 3274 | 158 | Nutty, roasted | 2.5 |
When 4,5-dimethylthiazole serves as a pharmaceutical intermediate, acylation and metalation at the 2-position exploit the absence of a blocking methyl substituent, and continuous-flow microreactors shift the selectivity beyond batch capabilities. Regioselective lithiation with n-butyllithium in tetrahydrofuran at −78°C yields the 2-lithio derivative, which reacts with dimethylformamide to give 4,5-dimethylthiazole-2-carboxaldehyde. In a Corning Advanced-Flow reactor with heart‑shaped mixing cells, a residence time of 2.3 s at −78°C generates the intermediate, and immediate inline quenching with DMF achieves an isolated yield of 95% after recrystallization from n‑heptane. The corresponding batch process in a jacketed vessel with a 4 h addition period typically yields 82%. The microreactor system’s enhanced heat-transfer efficiency suppresses dimerization and 5‑ring opening, shortcomings that limit batch scale‑up. For the synthesis of 2‑bromo‑4,5‑dimethylthiazole, bromination of the lithio intermediate with 1,2‑dibromotetrafluoroethane under identical flow conditions delivers 93% purity crude, upgraded to 99.5% by vacuum distillation. This unsubstituted 2‑position chemistry contrasts with 2‑methylthiazoles, where deprotonation competes with ring‑opening and electrophilic substitution is sluggish due to steric hindrance, making 4,5‑dimethylthiazole a preferred scaffold for late‑stage diversification in medicinal chemistry campaigns.
Release testing in accordance with the Food Chemicals Codex (FCC, 12th edition) relies on capillary gas chromatography with a polyethylene glycol stationary phase (DB‑WAX, 30 m × 0.32 mm ID, 0.25 µm film). The principal peak exhibits a retention index of 1145 under a temperature program from 60°C to 230°C at 5°C/min. Impurity profiling by GC‑MS in selected ion monitoring mode confirms residual 3‑chloro‑2‑butanone at ≤50 ppm and thioacetamide at ≤10 ppm. Water content determined by coulometric Karl Fischer titration (ISO 760) remains at ≤0.1%. Relative density measured by oscillating U‑tube densitometer per ASTM D4052-22 yields a typical value of 1.070 g/mL (range 1.065–1.075). Residual solvents—ethanol and ethyl acetate—are controlled individually below 100 ppm by static headspace GC. Elemental impurities, including lead (≤5 mg/kg) and arsenic (≤1 mg/kg), comply with ICH Q3D guidelines when tested by microwave‑assisted digestion followed by ICP‑MS.
The material is flushed with nitrogen and filled into epoxy‑lined steel drums. Storage at 2–8°C in sealed containers maintains specification compliance over a retest period of 24 months, with intermediate periodic testing at 12‑month intervals.
