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Biomedical subjects

J B McAlpine

Publications and source records attributed to J B McAlpine.

49 records · Page 3Linked to original sources

Arizonins, a new complex of antibiotics related to kalafungin. II. Isolation and characterization.

A new complex of anti-Gram-positive antibiotics was produced by the fermentation of Actinoplanes arizonaensis sp. nov. The antibiotics were recovered from the fermentation broth with Amberlite XAD-7 resin and from the mycelium by acetone lysis. UV, IR, MS and NMR spectral studies characterized these compounds as kalafungin-type antibiotics. They differ from other known members by an unusual oxidation pattern on the aromatic ring. They vary from one another by the degree and position of O-methylation on the aromatic ring and in the aliphatic portion of the molecules. The structure of one component was confirmed by X-ray diffraction analysis.

Actinomycetales↗

Tiacumicins, a novel complex of 18-membered macrolides. II. Isolation and structure determination.

A novel complex of Gram-positive antibiotics has been isolated from the fermentation broth and mycelium of Dactylosporangium aurantiacum subsp. hamdenesis subsp. nov. The structures of these six compounds were deduced employing UV, MS, IR, and extensive 1D and 2D homonuclear and heteronuclear NMR experiments. Each component contained a highly unsaturated 18-membered macrolide ring. Components differed from one another by minor structural variations in the macrolide ring and by the number and esterification pattern of glycosidically bound sugars.

Actinomycetales↗

Benzanthrins A and B, a new class of quinone antibiotics. II. Isolation, elucidation of structure and potential antitumor activity.

The benzanthrins, which were produced by Nocardia lurida, were extracted from the fermentation broth with CH2Cl2. Subsequent purification on Sephadex LH-20 and diolbonded silica gel, followed by countercurrent chromatography, afforded analytically pure benzanthrins A and B. FAB-MS revealed that benzanthrins A and B were isomeric. It was demonstrated through degradative and spectroscopic studies that the benzanthrins were di-glycosides of a trihydroxy benz[a]anthraquinone chromophore where one of the sugars was linked through carbon and the other through oxygen. Benzanthrins A and B differed in the stereochemistry of the O-glycosidic sugar. Both compounds inhibited the growth of Gram-positive bacteria and 9KB, 9PS and 9ASK tumor cells in tissue culture.

Animals↗

Lysinomicin, a new aminoglycoside antibiotic. II. Structure and stereochemistry.

The structure of lysinomicin, a new aminocyclitol antibiotic, was established as 3-epi-2'-N-(L-beta-lysyl)-4',5'-didehydro-6'-de-C-methylfortimi cin B (1) on the basis of spectral evidence and chemical degradation of the antibiotic. In the course of the degradation of 1, three additional compounds with interesting biological properties were obtained: 3-epi-2'-N-(L-beta-lysyl)-6'-de-C-methylfortimicin B (4), 3-epi-4',5'-didehydro-6'-de-C-methylfortimicin B (6) and 3-epi-6'-de-C-methylfortimicin B (7).

Aminoglycosides↗

Modification of seldomycin factor 5 at C-3'.

Attempted removal of the 3'-hydroxyl group of seldomycin factor 5 via displacement of a sulfonate ester has led to 3'-epi-seldomycin factor 5. Removal of the hydroxyl group has been effected by the Barton procedure. The antibacterial activity of 3'-epi- and 3'-deoxyseldomycin factor 5 against various aminoglycoside-resistant strains is discussed.

Anti-Bacterial Agents↗

The structures of the m-chloroperbenzoic acid oxidation products of 8,9-anhydroerythromycins A- and B-6,9-hemiacetal and of (8S)-8-hydroxyerythromycin B.

13C-NMR studies have confirmed the structures of (8S)-8-hydroxyerythromycins A- and B-6,9;9,11-acetal proposed by KROWICKI and ZAMOJSKI2,3) for the products of the m-chloroperbenzoic acid oxidation of 8,9-anhydroerythromycins A- and B-6,9-hemiacetal. The preparations of (8S)-8-methylthiomethoxy- and (8S)-8-methoxyerythromycin B-6,9;9,11-acetals are described. The latter are stable in aqueous acetic acid under conditions which convert (8S)-8-hydroxyerythromycin B-6,9;9,11-acetal into (8S)-8-hydroxyerythromycin B.

Acetates↗

A new aminoglycoside antibiotic complex--the seldomycins. III. The structures of seldomycin factors 1 and 2+.

The structures of seldomycin factors 1 and 2 have been determined by consideration of chemical degradation and spectral properties. Factor 1, also known as XK-88-1, is shown to be 6-O-(2-amino-2-deoxy-alpha-D-xylopyranosyl) paromamine (1) and factor 2, also known as XK-88-2, is shown to be 4'-deoxy-neamine (2). Mass spectral evidence has been obtained that suggests the most probable structure for seldomycin factor 3, also known as XK-88-3, is 6'-amino-6'-deoxyseldomycin factor 1 (12).

Amino Sugars↗