A new generation of triazine-based coupling reagents (TBCRs), designed according to the concept of "superactive esters", was obtained by treatment of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium (DMTMM) chloride with lithium or silver tetrafluoroborate. The structure of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium tetrafluoroborate was confirmed by X-ray diffraction. Activation of carboxylic acids by using this reagent proceeds via triazine "superactive ester". The coupling reagent was successfully used for the synthesis of Z-, Boc-, and Fmoc-protected dipeptides derived from natural and unnatural sterically hindered amino acids and for fragment condensation, in 80-100% yield and with high enantiomeric purity. The manual SPPS of the ACP(65-74) peptide fragment (H-Val-Gln-Ala-Ala-Ile-Asp-Tyr-Ile-Asn-Gly-OH) proceeded significantly faster than with TBTU or HATU, as well as the automated SPPS of the same fragment gave a purer product than by using TBTU or PyBOP. The reagent was also demonstrated to be efficient in on-resin head-to-tail cyclization of constrained cyclopeptides, in SPPS synthesis of Aib peptides, and in the synthesis of esters from appropriate acids, alcohols, and phenols. The high efficiency and versatility of this new generation of TBCRs confirm, for the first time, the usefulness of the concept of "superactive esters" in rational design of the structure of coupling reagents.

Synthesis of organic/inorganic hybrid materials is an area of growing interest as advantageous properties of disparate components can be combined into singular materials. In this study, nanosized silica gel hybrids were obtained by reaction between silanol groups of silica and 2,4-dichloro-6-methoxy-1,3,5-triazine (DCMT), which then reacted with p-phenylenediamine. Acylation of amine by 10-undecanoic acid, N-Fmoc-Lys(Boc)OH, and N-Boc-Ser(OH)OH was the final step. Friction performance of silicatriazine hybrids, evaluated with a microtribometer, can be ranked in the following order: 10-undecanoic acid >N-FmocLys(Boc)OH>p-phenylenediamine>N-Boc-Ser(OH)OH. It is inferred that all the hybrids are effective in reducing friction, in comparison to pure silica materials. The rearrangement of silica-triazine hybrid included the 10-undecanoic acid, induced by UV exposure, also confirmed further improvement of friction performance. This approach can be successfully applied to preparation of other ORMOSIL hybrids.