title: [Semisyntheses using proinsulin, II. Preparation and application of Nepsilon 29, Nepsilon 59-bis(methylsulfonylethoxycarbonyl)proinsulin (author's transl)].
abstract: 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 bis(tert-butoxycarbonyl)oxide, or with the citraconyl group, after reaction with citraconic anhydride. Whereas Nalpha 1-tert-butoxycarbonylproinsulin was achieved by direct alkoxycarbonylation, Nalpha 1-citraconylproinsulin was obtained from partial deprotection of the quantitatively acylated proinsulin. The Nalpha 1-protected proinsulin derivatives were further quantitatively reacted with N-(methylsulphonylethoxycarbonyloxy)succinimide. The tert-butoxycarbonyl group was next removed by treatment with trifluoroacetic acid, or the citraconyl group removed by mild acid (pH 2.2) treatment. The resulting Nepsilon 29, Nepsilon 59-bis(methylsulphonylethoxycarbonyl)proinsulin was used in model reactions with the mixed anhydride of tert-butoxycarbonylmethionine with the aim of standardizing the coupling conditions to be used in the eventual synthesis of preproinsulin.
mesh_terms: D000818:Animals; D002254:Carbonates; D002417:Cattle; D055598:Chemical Phenomena; D002621:Chemistry; D002949:Citraconic Anhydrides; D006863:Hydrogen-Ion Concentration; D007328:Insulin; D011384:Proinsulin / Q000031:analogs & derivatives* / Q000138:chemical synthesis*; D011498:Protein Precursors / Q000138:chemical synthesis*; D014269:Trifluoroacetic Acid
chemical_list: D002254:Carbonates; D002949:Citraconic Anhydrides; D007328:Insulin; D011498:Protein Precursors; C013737:preproinsulin; C027601:N-(epsilon29),N-(epsilon59)-bis(methylsulfonylethoxycarbonyl)proinsulin; D011384:Proinsulin; D014269:Trifluoroacetic Acid; C027600:bis(tert-butoxycarbonyl)oxide
vernacular_title: Semisynthesen, ausgehend von Proinsulin, II. Darstellung und Anwendung von Nepsilon 29, Nepsilon 59-bis(methylsulfonylethoxycarbonyl)-proinsulin.