Angewandte Chemie (International ed. in English), 53(44), 11766-11771 (2014-09-10)
Carbonic acid (H2CO3), an essential molecule of life (e.g., as bicarbonate buffer), has been well characterized in solution and in the solid state, but for a long time, it has eluded its spectral characterization in the gas phase owing to
Nepsilon 29, Nepsilon 59-Bis(methylsulfonylethoxycarbonyl)proinsulin was prepared from native beef proinsulin for its possible use in the semisynthesis of preproinsulin. The modification was made possible by first protecting the alpha-amino group of proinsulin either with the tert-butoxycarbonyl group, after reaction with
Journal of the American Chemical Society, 132(9), 2870-2871 (2010-02-18)
We report a fundamentally unique approach to the catalytic kinetic resolution of amine derivatives based on formamide and thioformamide substrates. Readily accessible histidine-containing peptides mediate the kinetic resolutions with as little as 5 mol % catalyst. Selectivity factors (k(rel)) as
Perchloric acid adsorbed on silica-gel (HClO4-SiO2) was found to be a new, highly efficient, inexpensive and reusable catalyst for chemoselective N-tert-butoxycarbonylation of amines at room temperature and under solvent-free conditions.
Total syntheses of two structures purported as (+)-heliananes were completed in six pots. Spectral comparisons, between the synthetic and natural compounds, revealed a misassignment of the eight-membered ring in the heliananes. The key step in the syntheses of the proposed
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