Masayuki Muroi

The structures of macbecin I and II : New antitumor antibiotics

Abstract Macbecin I 1 , C 30 H 42 N 2 O 8 , and macbecin II 2 , C 30 H 44 N 2 O 8 , were shown to be 2,6-disubstituted benzoquinone and hydroquinone derivatives by an oxidation-reduction relationship, UV. 1 H and 13 C 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 5 clarified 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 .

Isolation of maridomycins and structure of maridomycin II

Das ausStreptomyces hygroscopicus isolierte neue Makrolid Maridomycin II lässt sich mit Säure Mycarcose und Mycaminose spalten. Auf Grund der Oxidation ins Carbomycin sowie der spektroskopischen Daten wurde die Struktur als II erklärt.

The structures of macbecin I and II, new antitumor antibiotics

Abstract Structures of macbecin I (1) and II (2), new antitumor antibiotics isolated from the culture broth of Nocardia sp. No. C-14919, have been elucidated as benzenoid ansamycins on the basis of chemical evidence and spectral analyses.

Structures of maridomycin I, III, IV, V and VI, macrolide antibiotics

Strukturaufklärung einer Gruppe von Antibiotika aus der Reihe der Makrolide.

Chemical Modification of Maridomycin, a New Macrolide Antibiotic

Maridomycin, a new macrolide antibiotic, and tetrahydromaridomycin were acylated into their mono, di, and tri acyl derivatives. These derivatives were compared with the parent antibiotic, maridomycin, for their (i) in vitro antimicrobial activities, (ii) protective effect in mice infected with Staphylococcus aureus (oral administration), (iii) blood levels attained in rats, and (iv) acute toxicity in mice (intraperitoneal administration). All the derivatives showed either the same or less activity in vitro, but 9-acyl, 9, 2′-diacylmaridomycin and 9, 13, 2′-triacetyltetrahydromaridomycin demonstrated improved therapeutic effects together with higher blood levels and low toxicity. 9-Propionylmaridomycin showed the most favorable biological properties. Images