Certain features of will be down for maintenance the evening of Friday August 18th starting at 8:00 pm CDT until Saturday August 19th at 12:01 pm CDT.   Please note that you still have telephone and email access to our local offices. We apologize for any inconvenience.

Vol 2 No 4

Vol . 2, No. 4
Unnatural Amino Acids II
The latest Update on New Tools for Drug Discovery
Click here to download PDF version. (688 KB)


What is new?

Sigma-Aldrich is very pleased to highlight in this ChemFiles issue a completely new overview of our fast-growing product range of unnatural amino acids. If you would like to receive a hard copy of our first brochure featuring these innovative tools for drug discovery research (ChemFile Vol. 1 No. 5), please contact your local Sigma-Aldrich office. Alternatively, you may download an electronic copy by clicking the link above (PDF, 670 KB).

One-stop shopping

Sigma-Aldrich offers you all the tools you need for synthesizing peptides, from basics such as coupling reagents expanding to a range of around 600 unnatural amino acids. In this brochure you will find an overview of more than 90 New and unique building blocks for peptide-analogues and peptidomimetics research.

Contents of this ChemFile

Sigma-Aldrich is pleased to discuss in this ChemFile the following topics:

  • Cyclic Amino Acids
  • Diamino Acids
  • ß-Amino Acids and Homo Amino Acids
  • Alanine Derivatives
  • Phenylalanine Boronic Acids
  • Proline and Pyroglutamine Derivatives

New offerings in this rapidly expanding field are added monthly!

At Sigma-Aldrich we are committed to supplying you with reliable products, new technologies and unsurpassed service. A strong example of this commitment is the introduction of several thousands of new products every year. When you cannot find the amino acid you are looking for, we welcome your input and will use it to broaden our product range even further. Please contact us at with new suggestions!

ChemFiles on the web

Please take a look at the whole range of our ChemFiles brochures at When you prefer to obtain a paper copy of these brochures, please contact your local Sigma-Aldrich Office.

Are you interested in synthesizing FUNCTION?

The essential step in combinatorial chemistry is not the synthesis; rather it is finding a target, based on specific properties. Combinatorial synthetic research is an adaption to what nature has been doing all the time: synthesis followed by selection, as opposed to synthesis by design. The aim of combinatorial chemistry is primarily discovering a molecule, whereas that of chemical synthesis is constructing a molecule.

REFERENCES: Albert Eschenmoser, Chem. Intell. 2000, 6, 6.

Unnatural amino acids, utilized as building blocks, conformational constraints, molecular scaffolds or pharmacologically active products, represent a nearly infinite array of diverse structural elements for the development of new leads in peptidic and non-peptidic compounds. Small-molecule combinatorial libraries containing unnatural amino acid residues already show remarkable impact on drug discovery processes.1-5 Novel short-chain peptide ligand mimetics with both enhanced biological activity and proteolytic resistence are drug candidates in todays R&D pipelines of many pharmaceutical companies. Optimized and fine-tuned analogues of peptidic substrates, inhibitors or effectors are also excellent analytical tools for investigating signal transduction pathways or gene regulation.



  1. Bunin, B.A. et al., Annu. Rep. Med. Chem. 1999, 34, 267.
  2. Floyd, C. D. et al., Prog. Med. Chem. 1999, 36, 91.
  3. Borman, S. Chem. Eng. News 1999, 77, 33.
  4. Brown, R. K. Modern Drug Discovery 1999, 2, 63.
  5. Borman, S. Chem. Eng. News 2000, 78, 53.