English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Sir: The accomplishment of an efficient method for obtaining the previously unknown 1,3,2"',6"'tetra-N-acetylparomomycin (1) and the subsequent preparation of the pseudotrisaccharide 5-0[3-0(2,6-diami no-2,6-dideoxy-f-L-idopyranosyl)-/3-L-ribo-furanosyl]-2-deoxystreptamine(5), as described in the preceding papery, by nitrous acid deamination, suggested a route for providing a useful intermediate for the synthesis of novel aminoglycoside antibiotics related to paromomycin and neomycin and modified in the glucosamine moiety. In order to investigate the structure-activity requirements for the glycoside unit linked to the C-4 hydroxy group of 2-deoxvstreptamine and to obtain new analogues, we have undertaken the preparation of a selectively protected derivative of the pseudotrisaccharide 5 derived from paromomycin and lacking the glucosamine moiety. Reaction of 1,3,2"',6"'-tetra-N-acetylparomomycin (1)1) with benzyloxycarbonyl chloride gave the corresponding 2'-N-benzyloxycarbonyl derivative (2) (m.p. 198"200'C; [a]D +57°, MeOH), that was O-acetylated to give the fully acylated compound 3 (m.p. 269-271°C; [Lx],, + 56°, MeOH). Hydrogenolysis of the benzyloxycarbonyl group in acidic methanol on 10% palladium-carbon afforded 1,3,2"',6"'-tetra-N-acetyl-octa-O-acetylparomomycin (4) as the hydrochloride (nz.p. 200205°C; [a]D +62°, MeOH). Nitrous acid deamination of 4 gave a mixture containing two main products which were separated by column chromatography on silica gel. The less polar component was identified as 5-(acetoxymethyl)-2-furaldehyde after comparison with an authentic sample prepared by deamination of 1,3,4,6-tetraO-acetyl-2-amino-2deoxy-a-n-glucopyranose hydrochloride> . The major product (m.p. 157-160°C; [a]D +17', CHC13), obtained in an overall yield of 50%, was identified as 6-O-acetyl-1,3-di-N-acetyl-5-O[2, 5-di-O-acetyl-3-O-(2, 6d iacetamido 3, 4di -0acetyl-2, 6-dideoxy-/3-L-idopyranosyl)-/-D-ribofuranosyl]-2-deoxystreptamine. Since no analogues of paromomycin have been found to contain the 6-amino-6-deoxy-a-D-glycopyranosyl unit linked to the 4-position of the 2-deoxystreptamine ring, it seemed worthwhile to prepare such analogues from compound 6. For the glycosidation of compound 6, we applied the LEMIEUx-NAGABHUSHAN reaction which has been reported to give a-glycosides3> and which had been successfully used for the synthesis of kanamycin analogues". As an example of the general procedure, the synthesis of 9 is reported.

Semisynthetic aminoglycoside antibiotics. II. Synthesis of analogues of paromomycin modified in the glucosamine moiety.