110(P-36) チオストレプトン系抗生物質GE 2270Aの全合成研究(ポスター発表の部)

概要

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In recent years, various kinds of macrocyclic thiostrepton antibiotics containing polythiazolesubstituted pyridine skeleton, many thiazoleamino acid, and oxazoleamino acid moieties, have been isolated and structurally confirmed. The similar antibiotic, GE 2270A (1), isolated from the culture of Planobispora rosea, features a characteristic macrocyclic structure constructing of three conponents called Fragments A, B, and C. The synthesis of a central 2, 3, 6-tristhiazolylsubstituted pyridine skeleton [Fragment A (25)], followed by coupling with the protected thiazolylthiazole-4-carboxylate [Fragment B (12)] and then Boc-L-Ser(MOM)-L-Pro-NH_2 [Fragment C' (29)] gave a linear Fragment A-B-C'(31). Furthermore, firstly, deprotection of TPS group of 31 with TBAF, ester hydrolysis with 1 M LiOH, and then deprotection of both Boc and MOM groups with TFA, followed by macrocyclization of the deprotected intermediate derivative with BOP as condensing agent under high-dilution conditions. Finally, oxazoline ring formation of the Fragment C' segment with mesyl chloride (MsCl) in the presence of Et3N gave the expected synthetic 1.
2000-10-01