Spectinomycin modification. II. Spectinomycin C-3'-modification via diazoketone intermediates.
The C-3'-carbonyl group of N-protected spectinomycin is efficiently converted into a diazo group via base treatment of the corresponding tosylhydrazone. The diazo group imparts a new synthetically useful reactivity pattern on the sugar ring of the molecule. The synthesis of C-3'-deoxo-, monohalo- and dihalospectinomycins via the intermediacy of these diazo compounds is described. The reduced bioactivity of these analogs as compared to the parent and the C-3'-dihydro and aminospectinomycins established the need for hydrogen bonding groups in this region of the molecule for good activity, further refining the structure activity relationships in the spectinomycin series.
Spectinomycin modification. IV. The synthesis of 3'-aminomethyldihydrospectinomycins via spectinomycin 3'-cyanohydrins.
The C-3'-carbonyl group of N-protected spectinomycin is converted into the corresponding aminomethylalcohols via the intermediacy of cyanohydrins. Methodology for the selective synthesis of either epimer with retention of protection in the aminocyclitol ring provides valuable synthetic intermediates for the preparation of analogs of this important antibiotic. The new methodology provides an eff...متن کامل
Spectinomycin modification. V. The synthesis and biological activity of spectinomycin analogs with ring-expanded sugars.
Tiffeneau-Demjanov rearrangement of 3'-(R)-N,N'-dibenzyloxycarbonyl-3'-aminomethyl-dihydrospectinom ycin results in ring expansion affording the homologous analog with a seven-membered sugar ring. In stark contrast, attempted rearrangement of the 3'-S-isomer leads only to epoxide formation. Deprotection of the ring-expanded homolog gives homospectinomycin. The synthesis and biological activity ...متن کامل
A spontaneously arising nuclear mutation, ss-1, has been identified in Chlamydomonas reinhardtii that decreases both streptomycin and spectinomycin resistance levels about 10-fold after its introduction into all wild-type, streptomycin-resistant and spectinomycin-resistant strains examined. The mutations for resistance map to nuclear and uniparentally inherited (chloroplast) loci. In contrast, ...متن کامل
Acyl derivatives 5a approximately j and alkyl derivatives 7a approximately r of 4-dihydro-4-deoxy-4(R)-aminospectinomycin (1a) were prepared and tested for antibacterial activity. Only acyl compounds derived from long chain aliphatic acids showed activity in vitro, but were inactive when tested in vivo. All alkyl derivatives were active in vitro. In vivo however only the short chain derivatives...متن کامل
Ribosomes are made up of parts that interact so strongly that a mutation in one of them can mask the effect of mutation in another. For example, when a mutation to neomycin resistance, which is a ribosome mutation, is introduced into cells carrying a ribosome mutation to spectinomycin resistance, some of the doubly mutant strains were phenotypically sensitive to spectinomycin, even though the m...متن کامل