Abstract
The semisynthesis of Arg-A-(SS)2 is described by the following chemical and enzymatic procedures: 1) A-(SSO theta 3)4 was acylated with arginine N-carboxyanhydride by the known method. Arg-A-(SSO theta 3)4 was purified, reduced and oxidized to Arg-A(SS)2. When A(SS)2 was acylated under identical conditions a gel-like product was obtained which could be purified after oxidative sulfitolysis. This was then converted to Arg-A-(SS)2 as described above. Both the pathways gave the desired product in 20-25% yield. 2) Boc-Orn(Msc) was quantitatively attached to A-(SS)2 by the mixed anhydride method, the Msc group was then removed and the ensuing N delta-free amino function was amidinated. Traces of unconverted Orn derivative (less than 6%) were still present. 3) Boc-Arg(HBr) was attached to A-(SS)2 by the mixed anhydride method and Arg-A(SS)2 was isolated after removal of the Boc group in 25% yield. 4) Boc-Arg(DHCH) was attached to A-(SS)2 by the mixed anhydride method. DHCH and Boc groups were removed in two steps and Arg-A-(SS)2 was isolated in 29% yield. 5) Boc-Arg was condensed with A-(SS)2 by trypsin-catalyzed synthesis. The removal of Boc group and purification yielded the desired product in 40-42% yield. This procedure was the most efficient and proceeded stereospecifically.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: Hoppe-Seyler's Zeitschrift fur physiologische Chemie
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.