r Fluorous Technologies Technical Bulletin May 2005

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Bye Bye Biotin :  Fluorous Affinity Tags for Proteomics

Fluorous tags are used in many synthetic applications such as scavenging where the undesired components can be easily removed from a homogenous solution or as protecting groups where desired components can be easily isolated using fluorous purification techniques.  A new application recently reported at the 229th ACS National Meeting in San Diego and in the April 2005 issue of Nature Biotechnology involves specific peptide subsets being coupled with a fluorous affinity tag to aid in the characterization of these peptides.  Dr. Eric Peters and colleagues at the Genomics Institute of the Novartis Research Foundation have developed a technique for the enrichment and characterization of peptide subsets from a complex mixture using fluorous affinity tags.[1]  Several different classes of fluorous tags were used to selectively tag particular residues and post-translational modifications.  The tagged peptides can be readily isolated from the untagged peptides using a fluorous solid phase extraction, and the approach is highly compatible with MALDI/MS strategies.  By employing this novel technique, many of the limitations seen in traditional peptide enrichment such as high reagent cost and lower selectively have been overcome.

Fluorous Technologies has introduced a series of fluorous affinity tags for use in the proteomics area.  The fluorous iodoacetamide (for tagging thiol residues) and fluorous NHS ester (for tagging amines) are two of the compounds recently commercialized and are available in a range of fluorine contents.  Be sure to visit our "Fluorous Proteomics" webpage to learn more about this exciting new area and to place an order.

Join the Fluorous Technologies Team

FTI is actively looking for candidates to fill positions which are immediately available for work in cutting-edge aspects of fluorous chemistry.

POST-DOCTORAL RESEARCHER --  Qualified candidate will conduct postdoctoral research within currently funded NIH grants. Appropriate candidates will possess a Ph.D. in organic chemistry or separations sciences, a track record of research accomplishments, and excellent communication skills. Responsibilities include the design and execution of research within the goals of the grant, mentoring of junior lab personnel, and publication of research results. Areas of research include chiral separations, design and synthesis of new fluorous reagents and tags, and application of fluorous techniques to parallel synthesis.  Position could become permanent by mutual agreement.

SENIOR SCIENTIST -- Appropriate candidates will possess a Ph.D. in organic chemistry or separations sciences, 2-5 years relevant experience, a proven track record of research accomplishments, and excellent written and oral communication skills. Responsibilities include the design and administration of research, submission and procurement of grants, supervision of laboratory scientists, and publication of research results. Expertise in high-throughput synthesis, peptide or oligo chemistry is a plus.

Because of the urgent nature of the work, FTI is asking that all candidates be authorized for immediate employment in the United States.  If you are a chemist that has proven you can excel in a small, highly motivated team environment, this could be an excellent opportunity for you.  Please send resumes to Human Resources Director, Fluorous Technologies, Inc., 970 William Pitt Way, Pittsburgh, PA 15238 or email it to resumes-cen@fluorous.com

 

Recent Developments in Fluorous Chemistry

 

  FLUOROUS SYNTHESIS OF BIARYL-SUBSTITUTED PROLINE ANALOGS  A two-step protocol for parallel synthesis of biaryl-substituted proline analogs has been developed by Zhang, et al. at Fluorous Technologies, Inc.[2]  A perfluoroalkylsulfonyl-protected hydroxybenzaldehyde was used as the starting material.  In this multi-step synthesis that demonstrates the broad utility of fluorous chemistry, the fluorous sulfonyl group was used as  a phase tag, a protecting group and as a triflate equivalent to promote cross-coupling reactions.  This step was followed by a Pd-catalyzed Suzuki coupling reaction of the fluorous sulfonate with a boronic acid.  Both the reaction and separation processes for the synthesis of the bicyclic proline analogs were enhanced through the combined use of microwave technology and fluorous synthesis.

 


CHOICE OF FLUOROUS TAG DOES NOT AFFECT REACTIVITY   Recently the Curran group at the University of Pittsburgh completed a study of the relative reactivities of triphenylphosphine and light, medium and heavy fluorous triarylphosphines.[3] The four phosphines exhibited comparable performance in oxidation, alkylation and Staudinger reactions, and comparable yields were obtained in preparative Mitsunobu reactions.  These experiments showed that the phosphines can each be used interchangeably with a deciding factor on which phosphine to use determined by the method of separation.  Fluorous SPE can be used when working with the light fluorous triarylphosphine whereas liquid-liquid extraction works better for the medium and heavy fluorous phosphines.  Each of the phosphines is expected to outperform typical resin bound reagents when used at comparable level.



FLUOROUS MITSUNOBU APPLICATION NOTE -- UPDATED!  In an effort to provide the best possible resources for our customers we have begun the process of updating our Fluorous Application Notes.  The first Application Note to complete this process is for Fluorous Mitsunobu Chemistry - one of the most popular applications of fluorous chemistry to date.  Fluorous Mitsunobu chemistry uses the reagents Fluorous Triphenylphosphine (F17-TPP) and Fluorous Diazodicarboxylate (F-DIAD).  The application note will explain the benefits of using these reagents in your reaction as well as giving example reactions, including quantities of reagents and a stepwise procedure.  Our goal is to provide a general and robust protocol, so that our users can successfully complete the reaction and see for themselves the benefit of using fluorous chemistry in their research.  Purification chromatograms obtained from the cited reaction and "Insider tips" from our scientists are included for additional reference.  As always, please contact FTI for any questions or if you need any additional information.


Reprints of FTI-authored papers are available on request from FTI


References:

[1] Brittain, S.; Ficarro, S.; Brock, A.; Peters, E."Enrichment and analysis of peptide subsets using fluorous affinity tags and mass spectrometry" Nature Biotechnology 2005. 23(4), 463-468.

[2] Chen, C.; Zhang, W. "Fluorous synthesis of biaryl-substituted proline analogs by 1,3-dipolar cycloaddition and Suzuki coupling reactions" Tetrahedron Letters 2005, 46, 1807-1810.

[3] Wang, X.; Zhang, Q.; Curran, D. P. "Light, Medium and Heavy Fluorous Triarylphosphines Exhibit Comparable Reactivities to Triphenylphosphine in Typical Reactions of Triarylphosphines " J. Org. Chem. 2005. 70(9), 3716-3719.