1. Trityl isothiocyanate support for solid-phase synthesis
M C Pirrung, S V Pansare J Comb Chem. 2001 Jan-Feb;3(1):90-6. doi: 10.1021/cc000072m.
Trityl isothiocyanate resin [1], prepared from commercially available trityl chloride resin, is a useful precursor of the trityl thiosemicarbazide resin [2]. This resin can be employed in the solid-phase synthesis of a variety of supported isatin beta-thiosemicarbazones [4] and their Mannich derivatives [6]. A variety of thioureas [7] can be easily prepared by the reaction of [1] with amines. The supported thioureas are directly and efficiently converted to 2-aminothiazole-5-carboxylates [8] by reaction with methyl 2-chloroacetoacetate.
2. A Shelf Stable Fmoc Hydrazine Resin for the Synthesis of Peptide Hydrazides
Michael J Bird, Philip E Dawson Pept Sci (Hoboken). 2022 Sep;114(5):e24268. doi: 10.1002/pep2.24268. Epub 2022 Apr 16.
C-terminal hydrazides are an important class of synthetic peptides with an ever expanding scope of applications, but their widespread application for chemical protein synthesis has been hampered due to the lack of stable resin linkers for synthesis of longer and more challenging peptide hydrazide fragments. We present a practical method for the regeneration, loading, and storage of trityl-chloride resins for the production of hydrazide containing peptides, leveraging 9-fluorenylmethyl carbazate. We show that these resins are extremely stable under several common resin storage conditions. The application of these resins to solid phase peptide synthesis (SPPS) is demonstrated through the synthesis of the 40-mer GLP-1R agonist peptide "P5". These studies support the broad utility of Fmoc-NHNH-Trt resins for SPPS of C-terminal hydrazide peptides.
3. Method for activation and recycling of trityl resins
Itedale Namro Redwan, Morten Grøtli J Org Chem. 2012 Aug 17;77(16):7071-5. doi: 10.1021/jo300598d. Epub 2012 Aug 6.
This note describes a rapid and mild strategy for the loading of alcohols and anilines onto a polystyrene triphenylmethyl (trityl) resin. High loadings were obtained in a matter of minutes by treating resin-bound trityl chloride with triethyloxonium tetrafluoroborate followed by alcohols or anilines. Yields were comparable or better than known literature methods. Recycling of the recovered resin was also possible using the developed method.
