## 3 Results and Discussion
### Preparation of Ligands  
Concerning the synthesis of compound **2** (i.e., the C-glucose **1** bearing a suitable sulfur-ending linker), the following synthetic steps were carried out (see Scheme 2 which also includes the reaction conditions and yields of each step). Commercially available \(O\)-Me-\(\alpha\)-d-glucopyranoside was subjected to a chemoselective protecting-group-free C-allylation according to the procedure described in [60] (compound **6**). After perbenzylation (compound **7**), a successive electrolysis reaction, using a mixture of trifluoroacetic acid and acetic anhydride, allowed for the regioselective replacement of the benzyl protecting group on the C-6 position with an acetyl ester (compound **8**). The allyl handle was then manipulated by firstly oxidizing it into aldehyde **9**, then reducing it to alcohol **10**, and finally converting it into azidoethyl derivative **11** through a Mitsunobu-like reaction. The acetyl group was successively removed from the C6-OH position (compound **12**), which was in turn alkylated with the electrophilic TEG-C5 chain bearing a \(p\)-toluensulphonate function as leaving group (compound **14**). The tosylate linker **14** spacer was synthesized starting from triethyleneglycol, then monoalkylated with a 4-pentenyl chain (compound **13**) and finally reacted with tosyl chloride. In our first planned synthesis, we subjected compound **15** to \(\mathrm{BCl}_{3}\)-promoted benzyl ether deprotection, but we observed the simultaneous cleavage of the polyethyleneglycol chain. Hence, we decided firstly to subject the TEGylated sugar derivative to a radical-mediated reaction. Upon UV exposure at 365 nm and adding DPAP, a radical photoinitiator, the allyl group was converted into thioester **16**. Successively, we attempted to use both catalytic hydrogenolysis and Birch conditions for the azide reduction and benzyl group cleavage, but surprisingly, in both cases, complete removal of the thioester group, generating a pentyl-ending chain, occurred. Indeed, the desulfurization of thioester by SET (single electron transfer) processes is described and rationalized in the literature [72]. Therefore, a change in strategy was needed, so we proceeded with deprotecting the thioester group and promoting its transformation into a disulfide bond to obtain a kind of \"protected\" thiol derivative (compound **17**). Birch reduction of this compound led to the desired fully deprotected dimer **18**, the two amine functionalities of which were transformed into dansyl-sulfonamides, affording the final dimer **2**. This compound was used directly for the generation of the nanoparticles; it is possible to use both thiol-free and disulfide-bearing molecules, since the addition of an excess of NaBH\({}_{4}\) leads to the disulfide bridge reduction. The synthesis of the l-glutamine derivatives **4** and **5** proceeded with the following steps (Scheme 3). The tosyl group on the C5-TEG chain of compound **14** was converted into the azide functionality (compound **19**), which was reduced to amine derivative **20**. A condensation between this compound and Fmoc-l-Gln-Trt-OH afforded the TEGylated derivative **21**, which was subjected to protecting-group cleavage both in basic and acid conditions, affording the deprotected amino acid derivative **22**. The thiol-ene coupling (TEC) with thioacetic acid gave thioester **23**, which was then converted into the respective dimer **4** (the results was obtained from NMR analysis). The obtained disulfide was directly used for nanoparticle preparation. The condensation of amine **20** with Boc-l-Glu-O-tBu (Boc-l-glutamic acid 1-tert-butyl ester) gave intermediate **24**, which was deprotected by acidic conditions. The successive TEC with thioacetic acid afforded thioester **26**.