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R S Stanaszek

Publications and source records attributed to R S Stanaszek.

18 recordsLinked to original sources
PubMed1984

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↗
PubMed1982

4-N-Aminoacylation of substances derived from lysinomicin.

The preparations of 4-N-glycyllysinomicin and several 4-N-aminoacyl derivatives of compounds prepared from lysinomicin are presented. The new substances have lower antimicrobial activities than the original 4-N-unsubstituted lysinomicin derivatives. This result indicates that the structure-activity relationship observed with fortimicin A and fortimicin B does not apply to the lysinomicin derivatives studied.

Acylation↗
PubMed1982

Diastereomeric fortimicin 1,2-epoxides. The preparation of the 1-deamino-2-deoxyfortimicins A and B and the 1,2-di-epi-fortimicins A and B.

The preparation of 1,2-anhydro-2',6'-di-N-benzyloxycarbonyl-1-deaminofortimicin B-4,5-carbamate (4) and its conversion to the two diastereomeric 2',6'-di-N-benzyloxycarbonyl-1-deamino-2-deoxy-1,2-epoxyfortimicin B-4,5-carbamates 7 and 13 are described. The olefin 4 was used for preparation of 1-deamino-2-deoxyfortimicin A (6d) while the beta-epoxide 13 was used for the preparation of 1,2-di-epi-fortimicin A (17b) and 2-amino-1-deamino-2-deoxy-1-hydroxyfortimicin A (19c). The in vitro antibacterial activities of 6d, 17b and 19c are reported.

Aminoglycosides↗
PubMed1981

Substances derived from 4-de-N-methylfortimicin B.

The preparation of 4-de-N-methylfortimicin A analogs as well as the preparation of 4-de-N-methyl-4-N-(beta-aminoethyl)-4-N-ethylfortimicin B is reported. It was shown that the 4-N-methyl group in fortimicin analogs is essential for antibacterial activity since neither the 4-de-N-methylfortimicin A nor the 4-de-N-methyl-4-N-(beta-aminoethyl)-4-N-ethylfortimicin B exhibited useful biological activity.

Aminoglycosides↗
PubMed1979

4-N-Aminoacylfortimicins E.

The conversion of fortimicin E, a minor metabolite from the Micromonospora olivoasterospora fermentation which also produces fortimicin A and fortimicin B, to four 4-N-aminoacylfortimicins E was accomplished. The new 4-N-aminoacylfortimicins E showed only weak antimicrobial activity against several Gram-negative and Gram-positive microorganisms.

Aminoglycosides↗
PubMed1978

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↗
PubMed1978

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↗
PubMed1977

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↗
PubMed1977

Fortimicins A and B, new aminoglycoside antibiotics. III. Structural identification.

The structures of fortimicins A and B have been determined by PMR, CMR, mass spectra and CD combined with chemical degradations. Both antibiotics are pseudodisaccharides and incorporate a novel aminocyclitol, fortamine. In contrast to the diaminocyclitol moieties of known aminoglycosides, fortamine is a 1,4-diamine, contains both N- and O-methyl groups and possesses chiro stereochemistry. Both antibiotics are glycosides of 6-epi-purpurosamine B, but fortimicin A differs from fortimicin B by being a glycyl amide.

Aminoglycosides↗
PubMed1975

Spectinomycin modification. II. 7-EPI-sectinomycin.

7-Epi-spectinomycin (9) and 7-epi-4(R)-dihydrospectinomycin (10) have been prepared and their structure firmly established by proton magnetic resonance. Both of these spectinomycin analogs are devoid of antibiotic activity.

Chemical Phenomena↗