1. Honeycomb membranes prepared from 3-O-amino acid functionalized cellulose derivatives
William Z Xu, Batia Ben-Aroya Bar-Nir, John F Kadla Carbohydr Polym. 2014 Jan 16;100:126-34. doi: 10.1016/j.carbpol.2012.12.076. Epub 2013 Jan 18.
The development of value-added wood-derived polymer products is of significant importance. Of particular interest is the synthesis of advanced bioactive cellulosic materials. In the present research, novel cellulosic honeycomb films are reported. Cellulose was reacted with dimethylthexylsilyl chloride to form regioselective 2,6-di-O-thexyldimethylsilyl cellulose followed by substitution of the C3 with functionalized poly(ethylene glycol) (PEG). The free end of the PEG side chains of the regioselective 3-O-poly(ethylene glycol)-2,6-di-O-thexyldimethylsilyl cellulose served as an attachment point for bioactive molecules. As an example, Fmoc-Gly-OH was linked to the free end of PEG to produce 3-O-Fmoc-Gly-poly(ethylene glycol)-2,6-di-O-thexyldimethylsilyl cellulose. Honeycomb films were produced through film casting under a humid airflow. AFM analysis revealed the directed self-assembly of the 3-O-Fmoc-Gly-poly(ethylene glycol)-2,6-di-O-thexyldimethylsilyl cellulose wherein the pendent 3-O-Fmoc-Gly-poly(ethylene glycol) groups allocated preferentially around the edges of the honeycomb pores.
2. Efficient Method for the Concentration Determination of Fmoc Groups Incorporated in the Core-Shell Materials by Fmoc-Glycine
Elżbieta Szczepańska, Beata Grobelna, Jacek Ryl, Amanda Kulpa, Tadeusz Ossowski, Paweł Niedziałkowski Molecules. 2020 Sep 1;25(17):3983. doi: 10.3390/molecules25173983.
In this paper, we described the synthesis procedure of TiO2@SiO2 core-shell modified with 3-(aminopropyl)trimethoxysilane (APTMS). The chemical attachment of Fmoc-glycine (Fmoc-Gly-OH) at the surface of the core-shell structure was performed to determine the amount of active amino groups on the basis of the amount of Fmoc group calculation. We characterized nanostructures using various methods: transmission electron microscope (TEM), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) to confirm the modification effectiveness. The ultraviolet-visible spectroscopy (UV-vis) measurement was adopted for the quantitative determination of amino groups present on the TiO2@SiO2 core-shell surface by determination of Fmoc substitution. The nanomaterials were functionalized by Fmoc-Gly-OH and then the fluorenylmethyloxycarbonyl (Fmoc) group was cleaved using 20% (v/v) solution of piperidine in DMF. This reaction led to the formation of a dibenzofulvene-piperidine adduct enabling the estimation of free Fmoc groups by measurement the maximum absorption at 289 and 301 nm using UV-vis spectroscopy. The calculations of Fmoc loading on core-shell materials was performed using different molar absorption coefficient: 5800 and 6089 dm3 × mol-1 × cm-1 for λ = 289 nm and both 7800 and 8021 dm3 × mol-1 × cm-1 for λ = 301 nm. The obtained results indicate that amount of Fmoc groups present on TiO2@SiO2-(CH2)3-NH2 was calculated at 6 to 9 µmol/g. Furthermore, all measurements were compared with Fmoc-Gly-OH used as the model sample.
3. Dicyclopropylmethyl peptide backbone protectant
Louis A Carpino, et al. Org Lett. 2009 Aug 20;11(16):3718-21. doi: 10.1021/ol901310q.
The N-dicyclopropylmethyl (Dcpm) residue, introduced into amino acids via reaction of dicyclopropylmethanimine hydrochloride with an amino acid ester followed by sodium cyanoborohydride or triacetoxyborohydride reduction, can be used as an amide bond protectant for peptide synthesis. Examples which demonstrate the amelioration of aggregation effects include syntheses of the alanine decapeptide and the prion peptide (106-126). Avoidance of cyclization to the aminosuccinimide followed substitution of Fmoc-(Dcpm)Gly-OH for Fmoc-Gly-OH in the assembly of sequences containing the sensitive Asp-Gly unit.