$1631.00 - $4923.00
Boc-Asp(OMe)-OH is Nα-Boc-L-aspartic acid with the side-chain β-carboxyl group protected as a methyl ester. CAS 59768-74-0 and formula C10H17NO6 identify the 4-methyl ester; the current Alan H1 uses the abbreviation Boc-Asp(Oe)-OH, which should not be interpreted as an ethyl ester.
For a conventional Fmoc/tBu Asp building block, compare Fmoc-Asp(OtBu)-OH. The two products differ in both N-protection and side-chain ester chemistry.
Product Information
| Product Name | Boc-Asp(OMe)-OH |
| Catalog No. | AS2027 |
| CAS No. | 59768-74-0 |
| Molecular Formula | C10H17NO6 |
| Molecular Weight | 247.25 g/mol |
| Building Block Type | Nα-Boc-L-aspartic acid side-chain methyl ester |
| Primary Applications | Protected Asp intermediate synthesis; solution-phase peptide chemistry; side-chain ester route development; Boc-compatible coupling |
Why the Methyl Ester Is the Critical Identity Feature
A methyl ester and an ethyl or tert-butyl ester are different compounds with different masses and deprotection behavior. CAS 59768-74-0 is independently indexed as Boc-L-aspartic acid 4-methyl ester, so the protection state should be written as OMe in technical documentation.
Boc and OMe Do Not Share the Same Deprotection Trigger
Boc is acid-labile, while a methyl ester is generally removed by hydrolytic or saponification chemistry rather than simply disappearing during TFA cleavage. This can be useful when the side-chain carboxyl must remain protected through an acidic operation.
Asp Sequence Chemistry Still Requires Attention
Once Asp is incorporated into a peptide, downstream side reactions depend on the full sequence and synthesis conditions. The SPPS practical guide explains why side-chain protection alone does not define the entire behavior of an Asp-containing sequence.
Procurement and QC
Confirm CAS 59768-74-0, formula C10H17NO6, MW 247.25 g/mol, L stereochemistry, Nα-Boc protection, and the 4-methyl ester structure. Do not purchase this material based on the ambiguous 'Oe' abbreviation without checking the CAS and structure.
Procurement and QC Considerations
For an Asp-containing route that uses methyl-ester orthogonality, downstream hydrolysis and peptide-coupling steps can be evaluated through custom peptide synthesis.
Product Documents
A Safety Data Sheet (SDS / MSDS) is available for this product to support laboratory handling, storage and safety assessment.
Frequently Asked Questions
Is CAS 59768-74-0 an ethyl ester?
No. Independent supplier records identify it as Boc-Asp(OMe)-OH, the 4-methyl ester.
Which carboxyl group is free?
The α-carboxyl group is free for coupling; the side-chain β-carboxyl is methyl-ester protected.
How is OMe different from OtBu?
OMe generally requires hydrolysis for removal, while OtBu is acid-labile.