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What Is Boc2O (Di-tert-butyl Dicarbonate)?
Boc2O (Di-tert-butyl Dicarbonate) (CAS 24424-99-5) is a amino protecting group reagent with the molecular formula C10H18O5 and molecular weight 218.25 g/mol. [001]
Physical and Chemical Properties
| Property | Value | Source |
|---|---|---|
| CAS Number | 24424-99-5 | |
| Molecular Formula | C10H18O5 | |
| Molecular Weight | 218.25 g/mol |
Key Applications
- Boc Protection of Amines (The Universal Method): Boc2O is the standard reagent for introducing the tert-butoxycarbonyl (Boc) amino protecting group. RNH2 + Boc2O -> RNBoc + CO2 + tBuOH. Conditions: aq. NaOH or NaHCO3, dioxane/H2O, 0C to rt, 2-12 h. The Boc group is the cornerstone of solid-phase peptide synthesis (Boc-SPPS) and solution-phase amino acid protection. [004]
- Boc Protection of Amino Acids: Boc2O + amino acid (NaOH, dioxane/H2O) -> Boc-AA-OH in quantitative yield. Boc-protected amino acids are less expensive than Fmoc equivalents — preferred for large-scale peptide manufacturing where cost is critical. Boc group cleaved with TFA/CH2Cl2 (1:1, 30 min) or HCl/dioxane (4 M, 1 h). [004]
- Boc Protection of Guanidines & Heterocycles: Boc2O reacts with arginine guanidine (4 eq, NaOH, H2O/dioxane) to give Boc-Arg(Boc)2-OH — the standard protected arginine for SPPS. Boc2O protects imidazole (histidine), indole (tryptophan), and sulfonamide nitrogens. The di-Boc protection strategy enables selective mono-deprotection by controlling TFA concentration. [005]
- In-Situ Boc Anhydride Generation: Boc2O + NaN3 generates Boc-azide for amine protection in non-aqueous media. Boc2O + NH4HCO3/DMAP generates Boc-NH2 (tert-butyl carbamate) — a stable ammonia equivalent for Gabriel-like amine synthesis. These in-situ activation methods expand Boc chemistry beyond simple amine protection. [005]
- Boc Protection of Amines (The Universal Method): Boc2O is the standard reagent for introducing the tert-butoxycarbonyl (Boc) amino protecting group. RNH2 + Boc2O -> RNBoc + CO2 + tBuOH. Conditions: aq. NaOH or NaHCO3, dioxane/H2O, 0C to rt, 2-12 h. The Boc group is the cornerstone of solid-phase peptide synthesis (Boc-SPPS) and solution-phase amino acid protection. [004]
- Boc Protection of Amino Acids: Boc2O + amino acid (NaOH, dioxane/H2O) -> Boc-AA-OH in quantitative yield. Boc-protected amino acids are less expensive than Fmoc equivalents — preferred for large-scale peptide manufacturing where cost is critical. Boc group cleaved with TFA/CH2Cl2 (1:1, 30 min) or HCl/dioxane (4 M, 1 h). [004]
- Boc Protection of Guanidines & Heterocycles: Boc2O reacts with arginine guanidine (4 eq, NaOH, H2O/dioxane) to give Boc-Arg(Boc)2-OH — the standard protected arginine for SPPS. Boc2O protects imidazole (histidine), indole (tryptophan), and sulfonamide nitrogens. The di-Boc protection strategy enables selective mono-deprotection by controlling TFA concentration. [005]
- In-Situ Boc Anhydride Generation: Boc2O + NaN3 generates Boc-azide for amine protection in non-aqueous media. Boc2O + NH4HCO3/DMAP generates Boc-NH2 (tert-butyl carbamate) — a stable ammonia equivalent for Gabriel-like amine synthesis. These in-situ activation methods expand Boc chemistry beyond simple amine protection. [005]
Additional Applications
Key Applications
Representative Protocol
Application: Boc Protection of Amines (The Universal Method)
Typical Scale: Laboratory scale (1-100 mmol). For industrial scale, consult process chemistry references.
General Procedure: For boc protection of amines (the universal method), follow established protocols from the chemical literature and supplier technical documentation. Key parameters: use anhydrous solvents and reagents where moisture sensitivity is indicated; monitor reaction progress by TLC, HPLC, or GC-MS; standard aqueous workup (extraction with appropriate organic solvent, washing with brine, drying over Na2SO4 or MgSO4); purify by column chromatography, recrystallization, or distillation as appropriate for the product. For specific substrate combinations and optimized conditions, consult the referenced SOURCE materials in this article.
Quality Control: Confirm product identity by 1H/13C NMR, HRMS or LC-MS, and compare to literature data. For chiral products, determine enantiomeric excess by chiral HPLC or NMR with chiral shift reagents.
Safety Note: Conduct all operations in a properly functioning fume hood with appropriate PPE. Quench reactive intermediates/excess reagents according to established protocols before workup. Dispose of chemical waste in accordance with institutional and local regulations.
Troubleshooting:
- Low conversion: Check reagent purity (especially moisture-sensitive reagents). Ensure anhydrous conditions. Increase catalyst loading or reaction temperature. Verify substrate quality by NMR.
- Side product formation: Lower reaction temperature. Use more selective reagents or catalysts. Consider protecting group strategy for sensitive functional groups.
- Product decomposition during workup: Neutralize acids/bases before extraction. Use mild drying agents. Avoid prolonged exposure to silica gel if the product is acid-sensitive.
Handling and Storage
- GHS Hazard: H317: May cause an allergic skin reaction, H319: Causes serious eye irritation, H334: May cause allergy or asthma symptoms or breathing difficulties if inhaled
- Signal Word: Danger
- Pictograms: GHS05, GHS06, GHS07
- Storage: Store at 2-8 °C or as recommended. Keep container tightly closed in a cool, dry, well-ventilated area. Protect from moisture, heat, and direct sunlight. For compounds used in pharmaceutical or GMP applications, store in a dedicated area with controlled access and environmental monitoring. Always consult the supplier's SDS for lot-specific requirements.
- PPE: Nitrile gloves, safety goggles with side shields, lab coat, and closed-toe shoes. Work in a well-ventilated fume hood. Use respiratory protection (NIOSH-approved N95 or better) if handling large quantities or if the SDS indicates inhalation hazard. [002]
Always consult the Safety Data Sheet (SDS) from your supplier before handling. SDS documents are lot-specific — different purity grades and formulations may have different hazard classifications. For bulk handling, consult your institution's chemical hygiene plan and perform a job hazard analysis (JHA) before beginning work. Emergency procedures: in case of skin contact, wash immediately with soap and water for at least 15 minutes. For eye contact, rinse cautiously with water for several minutes and remove contact lenses if present. If inhaled, move to fresh air. Seek medical attention if symptoms persist.
Regulatory & Compliance
Chemical Inventories: Boc2O (Di-tert-butyl Dicarbonate) (CAS 24424-99-5) is listed on major chemical inventories including the TSCA (Toxic Substances Control Act) inventory in the United States, EINECS (European Inventory of Existing Commercial Chemical Substances) in the EU, and similar inventories in Japan (ENCS), China (IECSC), Korea (KECL), and Australia (AICS). The specific regulatory status of CAS 24424-99-5 should be verified with the appropriate national authority before importing into any jurisdiction, as inventory listing status can change with regulatory updates and new chemical assessments.
GHS Classification: Refer to the Handling and Storage section above for the Globally Harmonized System hazard classification. The GHS classification is harmonized across most jurisdictions, but specific national implementations (EU CLP Regulation, US OSHA HazCom 2012, China GB 30000 series) may have additional requirements.
Transport Information: Verify the proper shipping name, UN number, hazard class, and packing group with your supplier before shipping. Transport regulations (IATA/ICAO for air, IMDG for sea, ADR/RID for road/rail in Europe, 49 CFR for US ground) may impose quantity limits, packaging requirements, and documentation obligations. Some compounds may be classified as dangerous goods requiring specialized handling and certified packaging.
Export Control: Boc2O (Di-tert-butyl Dicarbonate) is a standard research and industrial chemical. However, always verify that no specific export control regulations apply to your destination country. Certain chemical categories (precursors, dual-use chemicals) may require export licenses under the Chemical Weapons Convention (CWC), Australia Group guidelines, or national export control laws. Contact your local trade compliance office for the most current regulatory guidance.
[004] [002]
Frequently Asked Questions
What is the CAS number of Boc2O (Di-tert-butyl Dicarbonate)?
The CAS Registry Number is 24424-99-5. Always specify the CAS number when ordering to ensure correct compound identification regardless of naming conventions. [001]
What is the molecular weight of Boc2O (Di-tert-butyl Dicarbonate)?
The molecular weight is 218.25 g/mol based on the molecular formula C10H18O5. Use this value to calculate molar equivalents, determine reaction stoichiometry, and prepare solutions of known concentration. [001]
What is Boc2O (Di-tert-butyl Dicarbonate) used for?
Boc2O (Di-tert-butyl Dicarbonate) is used for: Boc Protection of Amines (The Universal Method) (Boc2O is the standard reagent for introducing the tert-butoxycarbonyl (Boc) amin...); Boc Protection of Amino Acids (Boc2O + amino acid (NaOH, dioxane/H2O) -> Boc-AA-OH in quantitative yield. Boc-p...); Boc Protection of Guanidines & Heterocycles (Boc2O reacts with arginine guanidine (4 eq, NaOH, H2O/dioxane) to give Boc-Arg(B...). For detailed protocols, see the Key Applications section above. [002]
How should Boc2O (Di-tert-butyl Dicarbonate) be stored?
Store at 2-8 °C or as recommended. Keep container tightly closed in a cool, dry, well-ventilated area. Protect from moisture, heat, and direct sunlight. For compounds used in pharmaceutical or GMP applications, store in a dedicated area with controlled access and environmental monitoring. Always consult the supplier's SDS for lot-specific requirements.. Always consult the Safety Data Sheet (SDS) from your specific supplier for the most accurate storage recommendations. [002]
Where can I buy Boc2O (Di-tert-butyl Dicarbonate)?
Boc2O (Di-tert-butyl Dicarbonate) (CAS 24424-99-5) may be sourced through CoreyChem. For bulk pricing, custom packaging, and a certificate of analysis, submit an inquiry to our sales team with your CAS number, required quantity, and desired purity. [002]
Where to Buy
Boc2O (Di-tert-butyl Dicarbonate) (CAS 24424-99-5) is not currently listed in the CoreyChem catalog. Contact [email protected] for sourcing assistance. [003]
Our sourcing team can assist with procurement from qualified manufacturers worldwide. Please provide the CAS number, required quantity, and desired purity when submitting your inquiry for the fastest response.
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References & Sources
https://www.tcichemicals.com/US/en/search/?text=24424-99-5
https://pubchem.ncbi.nlm.nih.gov/compound/24424-99-5
https://pubchem.ncbi.nlm.nih.gov/compound/24424-99-5#section=Use-and-Manufacturing
