HCTU: A New Aminium Based Coupling Reagents Useful for Peptide Synthesis available from Peptides International

HCTU: A New Aminium Based Coupling Reagents
Useful for Peptide Synthesis

Made by Luxembourg Industries and available from Peptides International

A critical factor in the successful amide bond formation step during peptide synthesis is the selection of an appropriate activating or condensing reagent. We are pleased to report that a new coupling reagent with improved properties over traditional condensing agents is now available from Peptides International. This new reagent was developed by Luxembourg Industries in Israel (1) and performs as good or better than traditional reagents such as HBTU and PyBOP™. Reports indicate that HCTU shows improved peptide purity in the trial synthesis of Lys₁₀-Phe₃-Amide [K₁₀-F₃-Amide]. The synthesis utilized Rink Amide resin with standard Fmoc coupling protocols using 4 fold excess of amino acids and 8 fold excess of NMM in DMF. The crude peptide obtained after cleavage with Reagent K [TFA: H₂O: thioanisole: ethanedithiol; phenol 85:5:5:2.5:2.5] yielded higher purity with HCTU (97%) when compared to PyBOP (85%). Also stability studies have shown that HCTU remained colorless throughout typical and long peptide synthesis times therefore the reagent is considered to be quite stable. In addition HCTU reagent is reported to be non-poisonous, non-corrosive and is not a dermal irritant.

HCTU Structure as revealed by X-ray Crystal Analysis (1)

• Compatible with typical batch and automated
Fmoc synthesis strategies Performed better than PyBOP™

• Low extent of racemization

• Cost Effective

• Soluble in DMF and NMP

• Non-toxic, Non-irritant, Non-corrosive

• Stable solid, Solution stable for long synthesis times

A key element for developing a new condensing agent is the resulting stereochemistry of the amino acid; it is critical to maintain chiral integrity during chain elongation. Incorporation of a better leaving group during amide bond formation can lead to racemization of the alpha-carbon due to its increased acidity which promotes enolization and oxazolone formation during the activation step (2). Recently at the European Peptide Symposium Di Fenza and Rovero reported reduced rates of racemization when HCTU was used as the coupling reagent as compared to BOP. Overall, HCTU is an excellent, new coupling reagent that offers high yields and low levels of racemization. Please contact our technical specialist to discuss your specific project needs. Order your reagent today.

1. O. Marder, Y. Shvo, and F. Albericio HCTU and TCTU: New Coupling Reagents: Development and Industrial Applications Poster Presentation Gordon Conference February 2002.
2. A. Di Fenza and P. Rovero Racemization Studies on novel Cl-HOBt-based coupling reagents. Presented at the European Peptide Symposium, August 2002.
3. F. Albericio and S. A. Kates. Coupling methods: solid-phase formation of amide and ester bonds. In "Solid-Phase Peptide Synthesis, a Practical Guide", S. A. Kates and F. Albericio (Eds.), Marcel Dekker, New York, (2000) p. 275.

HCTU Product Brochure (PDF)

CODE	PRODUCT DESCRIPTION	QTY	USD
KHC-1018-PI NEW!	HCTU Reagent 1H-Benzotriazolium 1-[bis(dimethylamino)methylene] -5chloro-,hexafluorophosphate (1-),3-oxide (M.W. 413.69) C₁₁H₁₅CIF₆N₅OP [330645-87-9]	25 g 100 g	55 125
Bulk quantities available please contact our technical sales specialists to discuss your project needs..
Please contact Peptides International for ordering information. Peptides International, Inc. PO Box 24658 Louisville, Kentucky 40224 USA Phone: 502-266-8787 or 800-777-4779 Fax: 502-267-1FAX (1329) Email: peptides@pepnet.com
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