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The structures of macbecin I and II

1981; Elsevier BV; Volume: 37; Issue: 6 Linguagem: Inglês

10.1016/s0040-4020(01)92041-1

1464-5416

Masayuki Muroi, Konomi Haibara, Mitsuko Asai, KAZUHIDE KAMIYA, Toyokazu Kishi,

Microbial Natural Products and Biosynthesis

Macbecin I 1, C30H42N2O8, and macbecin II 2, C30H44N2O8, were shown to be 2,6-disubstituted benzoquinone and hydroquinone derivatives by an oxidation-reduction relationship, UV. 1H and 13C NMR spectra. Alkaline methanolysis of 1 gave a 2-aminobenzoquinone derivative 5, suggesting an ansa-structure for 1, and acid hydrolysis of 1 gave decarbamoyl products 9,10 and 11, indicative of the location of carbamoyloxy group in allylic position. Spin decoupling studies on 1,3 and 5clarified the partial structures [A], [B], [C] and [D]. From their mutual disposition two structures 1a and 1b, were proposed out of which 1a has been selected for the structure of 1 on the basis of the structure of oxidative degradation product 12. X-Ray analysis of the bromoacetyl derivative of 1 confirmed the above proposed structure and determined the absolute stereochemistry of 1 and 2.