Stereo-controlled synthesis of erythronolides A and B from 1,6-anhydro-β-D-glucopyranose (levoglucosan). Skeleton assembly in (C9 – C13) + (C7 – C8) + (C1 – C6) sequence

Kochetkov, N. K.; Sviridov, A. F.; Ermolenko, M. S.; Yashunsky, Dmitry V.; Borodkin, Vladimir S.

doi:10.1016/s0040-4020(01)81090-5

Cited by 43 publications

(7 citation statements)

References 27 publications

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“…Furthermore, the total syntheses of erythronolide A ( 2 ) was accomplished by Yonemitsu et al7 and Kochetkov et al8 as shown in Scheme (see also Figure 2) by the effective formation of the 14‐membered lactones 16b and 25b starting from seco‐acids 11b (R 1 Mes, R 2 H) and 22b (R 1 PMP, R 2 H), which have similar structures to those of 11a (R 1 Mes, R 2 H) and 22a (R 1 Me, R 2 H). In the former cyclization, the desired lactone 16b was easily obtained in 98% yield from the seco‐acid 11b by the modified Yamaguchi lactonization,9 and the later ring‐closure reaction was also successfully carried out using Corey's improved double‐activation method3,4 through a thiol ester intermediate generated from 22b to provide the corresponding lactone 25b in 71% yield.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the Efficiency of the Macrolactonization Using MNBA in the Synthesis of Erythromycin A Aglycon

Shiina

Katoh

Nagai

et al. 2009

The Chemical Record

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Various intermediates for the synthesis of erythronolide A, an aglycon of erythromycin A, are prepared from the corresponding seco-acids using 2-methyl-6-nitrobenzoic anhydride (MNBA) in the presence of 4-(dimethylamino)pyridine (DMAP) with or without triethylamine. The efficiency of the MNBA lactonization is assessed by studying this method and comparing the results with those of the other established macrocyclization protocols. It has been finally concluded that (i) the conformationally appropriate substrate for the monomeric cyclization gave the desired lactone in excellent yield under mild reaction conditions in the presence of MNBA and DMAP, (ii) the highly-strained substrate for the cyclization also afforded the monomeric lactone in relatively good yield at 100 degrees C in toluene, and (iii) the seco-acid having stable linear conformation, which preferred dimerizing more than forming the monomeric lactone, provided the corresponding diolide in high yield with the constant ratio of the monomer to dimeric lactone (approximately 1/5).

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Section: Introductionmentioning

confidence: 99%

Evaluation of the Efficiency of the Macrolactonization Using MNBA in the Synthesis of Erythromycin A Aglycon

Shiina

Katoh

Nagai

et al. 2009

The Chemical Record

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“…Several potent antimicrobial and antiviral agents such as Rimantadine [ 37 ], Oxadiazole [ 38 ], Isoxazole [ 39 ] and Thiadiazole [ 40 ] are all 1-adamantanyl derivatives. It was of great interest to note that Protea caffra produces levoglucosan ( Table 3 ), an important source of C1-C10 and C1-C13 carbon skeletons used to produce the antibiotics erythromycin A and B, [ 41 , 42 ]. 1-Heptacosanol, another compound detected in Protea caffra , is a fatty alcohol present in plants [ 43 ], marine algae [ 44 ] and cuttlefish, Sepiella inermis [ 45 ].…”

Section: Discussionmentioning

confidence: 99%

Antibacterial, Mutagenic Properties and Chemical Characterisation of Sugar Bush (Protea caffra Meisn.): A South African Native Shrub Species

Vambe

Aremu

Chukwujekwu

et al. 2020

Plants

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Protea caffra is used as a diarrhoeal remedy in South African herbal medicine, however, its pharmacological properties remain largely unknown. In the present study, extracts from different Protea caffra organs were screened against drug-sensitive and -resistant diarrhoeagenic pathogens using the microdilution assay (minimum inhibitory concentration, MIC). Twig extracts (70% methanol, MeOH) of the plant were purified and the resultant fractions screened for antibacterial properties (MIC). The chemical profiles of the fractions were determined by Gas Chromatography-Mass Spectrometry (GC-MS), while ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was used to quantify the phenolic acids in the plant. The mutagenic properties of bioactive extracts were assessed using the Ames test. The extracts demonstrated weak-moderate antibacterial properties (MIC: 0.3–0.6 mg/mL). A cold ethyl acetate fraction of MeOH twig extract exhibited significant antibacterial properties (MIC = 0.078 mg/mL) against Enterococcus faecalis. The presence of antibacterial compounds (1-adamantane carboxylic acid, heptacosanol, levoglucosan, nonadecanol) in the plant was putatively confirmed based on GC-MS analysis. Furthermore, UHPLC-MS/MS analysis revealed varying concentrations of phenolic acids (0.08–374.55 µg/g DW). Based on the Ames test, the extracts were non-mutagenic thereby suggesting their safety. To a certain degree, the current study supports the traditional use of Protea caffra to manage diarrhoea among local communities in South Africa.

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“…[13][14][15][16][17] In more recent times, levoglucosan (1) was used to prepare a variety of advanced chiral building blocks. [18][19][20][21][22][23] However, the rigid 1 C 4 conformation of 1 and the shielding by the 1,6-anhydro bridge also limits the stereochemical diversity. Only a comparatively small number of well defined isomeric branched methyl derivatives of 1 are readily available.…”

Section: Introductionmentioning

confidence: 99%

New Derivatives of Levoglucosan by Tandem Epoxide Allyl Alcohol Rearrangement‐Cuprate Cross‐Coupling

Krohn¹,

Gehle²,

Flörke³

2005

Eur J Org Chem

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Keywords: 1,6-Anhydro sugars / Chiral building blocks / Branched sugars / Č erný epoxide / Gilman cuprates / Epoxide rearrangement / Vinyl tosylate cross couplingThe alkylated allyl alcohols 6a, 7, and 8 (R = Me, Et, nBu) were formed in the reaction of the Č erný epoxide 3 with the Cyano-Gilman cuprates. The one-pot reaction was initiated by base-catalyzed epoxide allyl alcohol rearrangement to compound 5, followed by unprecedented vinyl tosylate crosscoupling with the cuprates, to form the alkylation products 6a, 7, and 8. The allyl alcohol 6a was transformed into a

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Stereo-controlled synthesis of erythronolides A and B from 1,6-anhydro-β-D-glucopyranose (levoglucosan). Skeleton assembly in (C9 – C13) + (C7 – C8) + (C1 – C6) sequence

Cited by 43 publications

References 27 publications

Evaluation of the Efficiency of the Macrolactonization Using MNBA in the Synthesis of Erythromycin A Aglycon

Evaluation of the Efficiency of the Macrolactonization Using MNBA in the Synthesis of Erythromycin A Aglycon

Antibacterial, Mutagenic Properties and Chemical Characterisation of Sugar Bush (Protea caffra Meisn.): A South African Native Shrub Species

New Derivatives of Levoglucosan by Tandem Epoxide Allyl Alcohol Rearrangement‐Cuprate Cross‐Coupling

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