Cleavage and deprotection of peptides on MBHA-resin with hydrogen bromide.
Wang. S S SS; Wang. B S BS; Hughes. J L JL; Leopold. E J EJ; Wu. C R CR; Tam. J P JP
Key Findings
- Dilute HBr in TFA with pentamethylbenzene and thioanisole efficiently cleaves and deprotects peptides on MBHA‑resin.
- The method can be scaled up to kilogram‑level production of thymosin‑alpha‑1.
- Isopropanol can replace acetonitrile in HPLC purification, lowering toxicity and cost.
Practical Outcomes
- For advanced DIY chemists, this protocol offers a greener, potentially cheaper way to finish and purify peptides like thymosin‑alpha‑1. It highlights safer solvent choices for HPLC, though handling HBr/TFA still requires proper lab safety measures.
Summary
The paper describes a new recipe for cutting and cleaning peptides off a solid support using a mix of hydrogen bromide and trifluoroacetic acid, which works well for making large amounts of thymosin‑alpha‑1, and shows that you can swap the usual toxic acetonitrile in HPLC purification for cheaper, safer isopropanol.
Abstract
Dilute hydrogen bromide in trifluoroacetic acid containing pentamethylbenzene and thioanisole was used in the cleavage and deprotection of peptides on MBHA-resin. Particular attention was paid to potential applicability of the method to kilogram scale synthesis of thymosin alpha 1. In the HPLC purification of the peptides, acetonitrile was replaced by relatively nontoxic isopropanol. The change should be economically and environmentally very attractive.
Study Information
pubmed
1992
10.1111/j.1399-3011.1992.tb00310.x