Stereoselective synthesis of pamamycin-607.
نویسندگان
چکیده
A macrodiolide antibiotic pamamycin-607 was synthesized by joining two hydroxy acid components. Three cis-2, 5-disubstituted tetrahydrofuran rings in the molecule were stereoselectively prepared by radical cyclization reactions of beta-alkoxyvinyl ketone intermediates and a beta-alkoxymethacrylate substrate. The key step of the synthesis is characterized by the predominant threo product formation in the radical cyclization reaction of a beta-alkoxymethacrylate intermediate.
منابع مشابه
Total synthesis of pamamycin-607.
Pamamycins are 16-membered macrodiolides isolated from Streptomyces alboniger and S. aurantiacus.1 They display autoregulatory, antibiotic, and anionophoric activities2 (Figure 1). Pamamycin-6071b-d is especially interesting for its potent activity2e against gram-positive bacteria (including multiple antibioticresistant strains of Mycobacterium tuberculosis) as well as against phytopathogenic f...
متن کاملRelationship between response to and production of the aerial mycelium-inducing substances pamamycin-607 and A-factor.
Respectively, exogenous pamamycin-607 and A-factor restored or stimulated aerial mycelium formation in 30 (67%) and 6 (13%) of 45 Streptomyces strains, and both restored or stimulated it in 5 strains (11%). Pamamycin-607 production was detected in 3 of those strains that responded to pamamycin-607. These findings indicate that pamamycin-607 acts on the common regulatory system for aerial myceli...
متن کاملIsolation, physico-chemical properties and biological activity of pamamycin-607, an aerial mycelium-inducing substance from Streptomyces alboniger.
Pamamycin-607, which showed aerial mycelium-inducing activity, has been isolated from Streptomyces alboniger IFO 12738. At 0.1 microgram/disc it induces aerial mycelia in the aerial mycelium-negative strain of S. alboniger but inhibits growth of the substrate mycelia at 10 micrograms/disc. It also acts as an antibiotic against some fungi and bacteria. When KMnO4 was partitioned with pamamycin-6...
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protonophoric agents10). The structural diversity of most of the published pamamycins has been ascribed to the substitution of protons or methyl groups at both parts of the macrodiolide ring by ethyl groups (see c. f. R1, R2, R3, R4 and R5 in Fig. 1)1,2,11). However, variations of the length of the nitrogen-containing side chain at the left side of the pamamycin skeleton (see c. f. R6 in Fig 1)...
متن کاملSTEREOSELECTIVE SYNTHESIS OF METHYL TETRA-0-METHYL a-AND P-D-GLUCO-AND MANNOPYRANOSIDES
Methyl tetra - 0-methyl- ?-D- glucopyranoside is stereoselectively prepared from tetramethyl-D- glucopyranose by using (MeI+NaH) in toluene (86%) or cyclohexane (85%), while its ?- isomer is best synthesized in hexamethyl phosphoramide (64%). Similarly, methyl tetra-o-methyl-?- D-mannopyranoside is synthesized in cyclohexane (80%), while its ?- isomer is predominantly prepared by (MeI+n-Bu...
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عنوان ژورنال:
- Journal of the American Chemical Society
دوره 124 49 شماره
صفحات -
تاریخ انتشار 2002