(R)-Methyl 2-Amino-2-(4-Hydroxyphenyl)Acetate: Low-Temp Viscosity Control
Technical Specifications and Purity Grades of (R)-Methyl 2-Amino-2-(4-Hydroxyphenyl)Acetate for Chiral Derivatization
In the realm of chiral derivatizing agents, (R)-Methyl 2-Amino-2-(4-Hydroxyphenyl)Acetate, also known as D-(-)-α-p-Hydroxy-phenylglycine methyl ester or Methyl (R)-(-)-Amino(4-Hydroxyphenyl)Acetate, stands as a cornerstone for enantiomeric resolution. As a drop-in replacement for existing chiral tagging reagents, our product offers identical performance with enhanced supply chain reliability. The compound, with CAS 37763-23-8, is typically supplied as a white to off-white crystalline powder. Standard industrial purity grades range from 98.0% to 99.5% (HPLC), with enantiomeric excess (ee) exceeding 99.0%. However, for critical applications, we recommend requesting batch-specific COA data, as trace impurities can influence derivatization efficiency. A key non-standard parameter we've observed in field applications is the material's hygroscopic nature: exposure to ambient moisture can lead to partial hydrolysis, forming the free acid, which may cause baseline noise in HPLC analysis. Therefore, storage under inert atmosphere is advised.
For procurement managers evaluating bulk pricing, our Methyl (R)-(-)-Amino(4-Hydroxyphenyl)Acetate bulk price analysis provides insights into cost drivers. Similarly, our wholesale pricing for Methyl (R)-(-)-Amino(4-Hydroxyphenyl)Acetate article details market trends. The synthesis route typically involves esterification of D-p-hydroxyphenylglycine, and our manufacturing process ensures consistent quality. As a global manufacturer, we offer custom synthesis for specific purity requirements.
| Parameter | Standard Grade | High Purity Grade |
|---|---|---|
| Assay (HPLC) | ≥98.0% | ≥99.5% |
| Enantiomeric Excess | ≥99.0% | ≥99.5% |
| Melting Point | 102-106°C | 103-105°C |
| Specific Rotation [α]D20 | -138° to -142° (c=1, MeOH) | -139° to -141° (c=1, MeOH) |
| Moisture (Karl Fischer) | ≤0.5% | ≤0.2% |
Solvent Incompatibility Risks and Viscosity Anomalies in Non-Polar Media at Sub-Zero Temperatures
When employing (R)-Methyl 2-Amino-2-(4-Hydroxyphenyl)Acetate in low-temperature chiral derivatization, solvent selection is critical. In non-polar solvents such as hexane or toluene, the compound exhibits limited solubility at room temperature, which can lead to precipitation at sub-zero conditions. However, a more subtle issue is a viscosity shift: at temperatures below -20°C, solutions in dichloromethane or THF can become unexpectedly viscous, hindering mixing and mass transfer. This is not a standard specification but a field observation: the amino ester can form transient aggregates via hydrogen bonding, increasing solution viscosity. To mitigate this, we recommend using a co-solvent system, such as THF with 5-10% DMF, which disrupts aggregation and maintains fluidity. Additionally, avoid prolonged exposure to protic solvents like methanol at low temperatures, as transesterification can occur, generating methyl esters of the solvent and compromising chiral purity.
Mechanical Stirring Adjustments and Process Optimization for Low-Temperature Derivatization Kinetics
For industrial-scale reactions, the viscosity anomalies necessitate mechanical stirring adjustments. When scaling up, use a pitched-blade turbine or anchor impeller to ensure homogeneous mixing, especially in jacketed reactors cooled to -30°C. We've found that maintaining a tip speed of 1.5-2.0 m/s prevents dead zones where the reagent may crystallize. Another edge-case behavior: the compound's reactivity with acid chlorides can be sluggish at low temperatures, requiring extended reaction times. To accelerate kinetics without raising temperature, consider pre-activation with a coupling agent like HOBt or HOAt, which forms a more reactive ester. This approach has been successfully applied in the synthesis of diastereomeric amides for chiral HPLC analysis.
Batch-Specific COA Parameters and Bulk Packaging for Industrial-Scale Chiral Resolution
Each batch of (R)-Methyl 2-Amino-2-(4-Hydroxyphenyl)Acetate is accompanied by a Certificate of Analysis (COA) detailing critical parameters. Please refer to the batch-specific COA for exact values, but typical specifications include appearance (white crystalline powder), identification (IR, NMR), assay, enantiomeric excess, melting point, specific rotation, loss on drying, and residue on ignition. For bulk supply, we offer packaging in 25kg fiber drums with inner PE bags, or 210L steel drums for larger quantities. Our logistics focus on physical packaging integrity to prevent moisture ingress during transit. As a factory supply partner, we can accommodate custom packaging requirements.
Frequently Asked Questions
What is the CAS number of methyl 2 4 hydroxyphenyl acetate?
The CAS number for (R)-Methyl 2-Amino-2-(4-Hydroxyphenyl)Acetate is 37763-23-8. This is distinct from methyl 2-(4-hydroxyphenyl)acetate, which has CAS 14199-15-6. Ensure you are ordering the correct chiral amino ester for derivatization.
What are the optimal solvent ratios for low-temperature coupling with (R)-Methyl 2-Amino-2-(4-Hydroxyphenyl)Acetate?
For low-temperature reactions, a mixture of anhydrous THF and DMF (9:1 v/v) provides good solubility and low viscosity down to -40°C. Avoid pure dichloromethane below -20°C due to viscosity increase. Always use freshly distilled solvents to prevent side reactions.
How can I manage viscosity issues when using this reagent in non-polar media?
If you observe high viscosity, add 5-10% of a polar aprotic co-solvent like DMF or NMP. Alternatively, gentle warming to -10°C before reagent addition can reduce viscosity without significant racemization. Mechanical stirring with a high-torque overhead stirrer is recommended.
How does the reactivity of (R)-Methyl 2-Amino-2-(4-Hydroxyphenyl)Acetate compare to other chiral tagging reagents?
This reagent offers comparable reactivity to (R)-1-(1-naphthyl)ethylamine but with better UV detectability due to the phenyl ring. It reacts smoothly with carboxylic acids via mixed anhydride or carbodiimide coupling. For amino acid analysis, it provides excellent resolution of D/L isomers.
Sourcing and Technical Support
As a leading supplier of chiral intermediates, NINGBO INNO PHARMCHEM CO.,LTD. ensures consistent quality and reliable supply of (R)-Methyl 2-Amino-2-(4-Hydroxyphenyl)Acetate. Our technical team can assist with method development and scale-up challenges. For detailed product information, visit our (R)-Methyl 2-Amino-2-(4-Hydroxyphenyl)Acetate product page. Partner with a verified manufacturer. Connect with our procurement specialists to lock in your supply agreements.