Synthetic macromolecular MUC1 glycopeptides have been used to unravel molecular mechanisms in antibody recognition of disease-specific epitopes. We have established a novel synthetic strategy for MUC1 tandem repeats having complex O-glycosylation states at each repeating unit based on convergent solid-phase fragment condensation under microwave irradiation. We have accomplished the synthesis of 77 amino acid MUC1 glycopeptides (MW = 12 759) having three major antigenic O-glycoforms [Tn, core 1 (T), and core 2 structures] at 10 designated positions out of 19 potential O-glycosylation sites. We demonstrate that the macromolecular MUC1 glycopeptide displaying the essential glycopeptidic neoepitope Pro-Asp-Thr(sialyl-T)-Arg-Pro-Ala-Pro at two different tandem repeats is an excellent serum MUC1 model showing ideal stoichiometric binding with anti-KL6/MUC1 antibody in the sandwich ELISA to quantify human serum KL6/MUC1 levels as a critical biomarker of interstitial lung diseases.
We developed a simple synthetic route to S-2367 (Velneperit) (1) using trans-1-ethoxycarbonyl-4-aminocyclohexane hydrochloride salt (12) as a starting material. The key step was Na 2 WO 4 /H 2 O 2 oxidation, and we found that it was accelerated in weakly basic conditions. The finding was useful to control one of the critical impurities: 14 in 10. The new process was more efficient than the early process from the viewpoint of the number of reactions, yield, throughput, and EHS (environment, health, and safety) but a quality deviation occurred in the pilot manufacturing: 10 content in 1 was over the upper limit. The cause was presumed to be hydrolysis of 1 during the recrystallization step. After finding it, we developed two reliable purification processes. The first was slurry washing including clever polymorphic control using only acetone and water. The second was salt formation of 10 and rational building of the recrystallization procedure based on solubility to improve removal rate.
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