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(S)-2-Methylpyrrolidine-2-Carboxylic Acid Hydrochloride is the hydrochloride salt of 2-methyl-L-proline, an α-methylated proline analog. The methyl substituent is located at the same carbon that bears the carboxyl group, increasing substitution around the proline backbone.
This compound is not preprotected for routine Fmoc-SPPS. Its main value is as a stereodefined noncanonical amino-acid intermediate that can be converted into an appropriate protected derivative before peptide incorporation. The broader design role of such residues is discussed in noncanonical amino acids in peptide discovery.
Product Information
| Product Name | (S)-2-Methylpyrrolidine-2-Carboxylic Acid Hydrochloride |
| Catalog No. | AS2065 |
| CAS No. | 1508261-86-6 |
| Molecular Formula | C6H12ClNO2 |
| Molecular Weight | 165.62 g/mol |
| Building Block Type | Free 2-methyl-L-proline hydrochloride |
| Primary Applications | Noncanonical amino-acid derivatization; conformational peptide SAR; protected building-block preparation; constrained scaffold research |
Why α-Methylproline Is More Constrained Than Proline
Proline already restricts backbone geometry because its nitrogen is part of the pyrrolidine ring. Adding an α-methyl group further increases substitution around the backbone center and can change local conformational preferences. The effect on activity or protease stability must be measured in the completed peptide.
The Hydrochloride Salt Matters
The product is supplied as a 1:1 hydrochloride salt, so the formula and molecular weight include HCl. Salt state should be confirmed when calculating equivalents or converting the material into another protected derivative.
Protection Is Required Before Routine SPPS
The ring nitrogen is not Fmoc- or Boc-protected. Direct use in a standard automated Fmoc cycle would therefore be inappropriate without prior derivatization. We recommend defining the desired temporary N-protecting group and any downstream deprotection requirements before converting the free amino acid.
Procurement and QC
Confirm CAS 1508261-86-6, C6H12ClNO2, MW 165.62 g/mol, S configuration, and hydrochloride salt state. Enantiomeric identity cannot be established by routine mass spectrometry alone.
For a sequence using 2-methylproline as a conformational probe, Alan Scientific can evaluate protected-building-block preparation and incorporation through custom peptide synthesis with noncanonical residues.
Product Documents
A Safety Data Sheet (SDS / MSDS) is available for this product to support laboratory handling, storage and safety assessment.
(S)-2-Methylpyrrolidine-2-Carboxylic Acid Hydrochloride MSDS
Certificates of Analysis (COAs) are batch-specific. Please contact us to request the COA for your product, and we will provide it by email.
Frequently Asked Questions
What is this compound commonly called?
It is commonly described as (S)-2-methylproline hydrochloride or 2-methyl-L-proline HCl.
Can it be used directly in standard Fmoc-SPPS?
Not as supplied. The ring nitrogen first requires an appropriate protection strategy.
Why use 2-methylproline?
It provides a more substituted, conformationally constrained proline analog for peptide SAR.
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