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Search for "partial synthesis" in Full Text gives 7 result(s) in Beilstein Journal of Organic Chemistry.
Natural resorcylic lactones derived from alternariol
- Joachim Podlech
Beilstein J. Org. Chem. 2024, 20, 2171–2207, doi:10.3762/bjoc.20.187
Graphical Abstract
Figure 1: Examples of compounds covered in this review categorized in six sub-classes (see text).
Figure 2: Examples of compounds not covered in this review.
Figure 3: Wrongly assigned and thus obsolete structures (details will be discussed in the respective chapters...
Figure 4: Alternariol with the correct IUPAC numbering and an occasionally used numbering based on the biphen...
Figure 5: Alternariol O-methyl ethers.
Figure 6: Alternariol O-glycosides.
Figure 7: Alternariol O-acetates and O-sulfates.
Figure 8: 2-Hydroxy- and 4-hydroxy-substituted alternariol and its O-methyl ethers.
Figure 9: Chloro- and amino-substituted alternariol and its O-methyl ethers.
Figure 10: Presumed alternariol derivatives with non-canonical substitution pattern.
Figure 11: Alternariol derivatives with the 1-methyl group hydroxylated.
Figure 12: Verrulactones: pseudo-dimeric derivatives of altertenuol and related compounds.
Figure 13: Biaryls formed by reductive lactone opening and/or by decarboxylation.
Figure 14: Altenuene and its diastereomers.
Figure 15: 9-O-Demethylated altenuene diastereomers.
Figure 16: Acetylated and methylated altenuene diastereomers.
Figure 17: Altenuene diastereomers modified with lactic acid, pyruvic acid, or acetone.
Figure 18: Neoaltenuene and related compounds.
Figure 19: Dehydroaltenusin and its derivatives.
Scheme 1: Equilibrium of dehydroaltenusin in polar solvents [278].
Figure 20: Further quinoid derivatives.
Figure 21: Dehydroaltenuenes.
Figure 22: Complex aggregates containing dehydroaltenuene substructures and related compounds.
Figure 23: Dihydroaltenuenes.
Figure 24: Altenuic acids and related compounds.
Figure 25: Cyclopentane- and cyclopentene-fused derivatives.
Figure 26: Cyclopentenone-fused derivatives.
Figure 27: Spiro-fused derivatives and a related ring-opened derivative.
Figure 28: Lactones-fused and lactone-substituted derivatives.
Scheme 2: Biosynthesis of alternariol [324].
Scheme 3: Biosynthesis of alternariol and its immediate successors with the genes involved in the respective ...
Scheme 4: Presumed formation of altenuene and its diastereomers and of botrallin.
Scheme 5: Presumed formation of altenuic acids and related compounds.
Scheme 6: A selection of plausible biosynthetic paths to cyclopenta-fused metabolites. (No stereochemistry is...
Scheme 7: Biomimetic synthesis of alternariol (1) by Harris and Hay [66].
Scheme 8: Total synthesis of alternariol (1) by Subba Rao et al. using a Diels–Alder approach [34].
Scheme 9: Total synthesis of alternariol (1) using a Suzuki strategy by Koch and Podlech [62], improved by Kim et...
Scheme 10: Total synthesis of alternariol (1) using an intramolecular biaryl coupling by Abe et al. [63].
Scheme 11: Total synthesis of altenuene (54) and isoaltenuene (55) by Podlech et al. [249].
Scheme 12: Total synthesis of neoaltenuene (69) by Podlech et al. [35].
Scheme 13: Total synthesis of TMC-264 (79) by Tatsuta et al. [185].
Scheme 14: Total synthesis of cephalosol (99) by Koert et al. [304].
Formal total synthesis of macarpine via a Au(I)-catalyzed 6-endo-dig cycloisomerization strategy
- Jiayue Fu,
- Bingbing Li,
- Zefang Zhou,
- Maosheng Cheng,
- Lu Yang and
- Yongxiang Liu
Beilstein J. Org. Chem. 2022, 18, 1589–1595, doi:10.3762/bjoc.18.169
- ]phenanthridine derivatives and further assessments of their bioactivities are currently in progress in our laboratory. Classification of benzo[c]phenanthridine alkaloids. Representative synthetic strategies for macarpine (1). Retrosynthetic analysis of marcarpine precursor 12 for a partial synthesis. Syntheses
Graphical Abstract
Scheme 1: Classification of benzo[c]phenanthridine alkaloids.
Scheme 2: Representative synthetic strategies for macarpine (1).
Scheme 3: Retrosynthetic analysis of marcarpine precursor 12 for a partial synthesis.
Scheme 4: Syntheses of precursors 5 and 8.
Scheme 5: Synthesis of enol silyl ether 10.
Scheme 6: Formal total synthesis of macarpine (1).
Efficiency Effsyn of complex syntheses as multicomponent reactions, its algorithm and calculations based on concrete criteria
- Heiner Eckert
Beilstein J. Org. Chem. 2019, 15, 1425–1433, doi:10.3762/bjoc.15.142
- process control, in the cost analysis of complex syntheses (Equation 5). An App based on this algorithm can offer an effective way to obtain a rapid overview of the total or partial synthesis. It can be used to evaluate and even control the synthesis from various aspects, including how it is affected by
Graphical Abstract
Scheme 1: Case study of a complex synthesis, parallel reactions. 10 possible synthesis STMs in green, other 1...
Scheme 2: Ordered reactions of the above complex synthesis to a main reaction set and connected parallel reac...
Scheme 3: Section A–J case study of Scheme 2 with operations of yoa calculation.
Scheme 4: Sequential synthesis and fragment linking of a decapeptide with comparison of results in Equations ...
Scheme 5: U-4CR with 17 precursors in the total synthesis of Et-743 (1) [14].
Scheme 6: Synthesis of 4 as key step of (+)-20S-camptothecin (3) total synthesis.
The chemistry and biology of mycolactones
- Matthias Gehringer and
- Karl-Heinz Altmann
Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159
Graphical Abstract
Figure 1: Initial proposal for the core macrolactone structure (left) and the established complete structure ...
Figure 2: Mycolactone congeners and their origins.
Figure 3: Misassigned mycolactone E structure according to Small et al. [50] (11) and the correct structure (6) f...
Figure 4: Schematic illustration of Kishi’s improved mycolactone TLC detection method exploiting derivatizati...
Figure 5: Fluorescent probes derived from natural mycolactone A/B (1a,b) or its synthetic 8-desmethyl analogs...
Figure 6: Tool compounds used by Pluschke and co-workers for elucidating the molecular targets of mycolactone...
Figure 7: Synthetic strategies towards the extended mycolactone core. A) General strategies. B) Kishi’s appro...
Scheme 1: Kishi’s 1st generation approach towards the extended core structure of mycolactones. Reagents and c...
Scheme 2: Kishi’s 2nd generation approach towards the extended core structure of mycolactones. Reagents and c...
Scheme 3: Kishi’s 3rd generation approach towards the extended core structure of mycolactones. Reagents and c...
Scheme 4: Negishi’s synthesis of the extended core structure of mycolactones. Reagents and conditions: a) (i) ...
Scheme 5: Burkart’s (incomplete) 1st generation approach towards the extended core structure of mycolactones....
Scheme 6: Burkart’s (incomplete) 1st, 2nd and 3rd generation approach towards the extended mycolactone core s...
Scheme 7: Altmann’s synthesis of alkyl iodide 91. Reagents and conditions: a) (i) PMB-trichloroacetimidate, T...
Scheme 8: Final steps of Altmann’s synthesis of the extended core structure of mycolactones. Reagents and con...
Scheme 9: Basic principles of the Aggarwal lithiation–borylation homologation process [185,186].
Scheme 10: Aggarwal’s synthesis of the C1–C11 fragment of the mycolactone core. Reagents and conditions: a) Cl...
Scheme 11: Aggarwal’s synthesis of the linear C1–C20 fragment of the mycolactone core. Reagents and conditions...
Figure 8: Synthetic strategies towards the mycolactone A/B lower side chain.
Scheme 12: Gurjar and Cherian’s synthesis of the C1’–C8’ fragment of the mycolactone A/B pentaenoate side chai...
Scheme 13: Gurjar and Cherian’s synthesis of the benzyl-protected mycolactone A/B pentaenoate side chain. Reag...
Scheme 14: Kishi’s synthesis of model compounds for elucidating the stereochemistry of the C7’–C16’ fragment o...
Scheme 15: Kishi’s synthesis of the mycolactone A/B pentaenoate side chain. (a) (i) NaH, (EtO)2P(O)CH2CO2Et, T...
Scheme 16: Feringa and Minnaard's incomplete synthesis of mycolactone A/B pentaenoate side chain. Reagents and...
Scheme 17: Altmann’s approach towards the mycolactone A/B pentaenoate side chain. Reagents and conditions: a) ...
Scheme 18: Negishi’s access to the C1’–C7’ fragment of mycolactone A. Reagents and conditions: a) (i) n-BuLi, ...
Scheme 19: Negishi’s approach to the C1’–C7’ fragment of mycolactone B. Reagents and conditions: a) (i) DIBAL-...
Scheme 20: Negishi’s synthesis of the C8’–C16’ fragment of mycolactone A/B. Reagents and conditions: a) 142, BF...
Scheme 21: Negishi’s assembly of the mycolactone A and B pentaenoate side chains. Reagents and conditions: a) ...
Scheme 22: Blanchard’s approach to the mycolactone A/B pentaenoate side chain. a) (i) Ph3P=C(Me)COOEt, CH2Cl2,...
Scheme 23: Kishi’s approach to the mycolactone C pentaenoate side chain exemplified for the 13’R,15’S-isomer 1...
Scheme 24: Altmann’s (unpublished) synthesis of the mycolactone C pentaenoate side chain. Reagents and conditi...
Scheme 25: Blanchard’s synthesis of the mycolactone C pentaenoate side chain. Reagents and conditions: a) (i) ...
Scheme 26: Kishi’s synthesis of the tetraenoate side chain of mycolactone F exemplified by enantiomer 165. Rea...
Scheme 27: Kishi’s synthesis of the mycolactone E tetraenoate side chain. Reagents and conditions: a) (i) CH2=...
Scheme 28: Wang and Dai’s synthesis of the mycolactone E tetraenoate side chain. Reagents and conditions: a) (...
Scheme 29: Kishi’s synthesis of the dithiane-protected tetraenoate side chain of the minor oxo-metabolite of m...
Scheme 30: Kishi’s synthesis of the mycolactone S1 and S2 pentaenoate side chains. Reagents and conditions: a)...
Scheme 31: Kishi’s 1st generation and Altmann’s total synthesis of mycolactone A/B (1a,b) and Negishi’s select...
Scheme 32: Kishi’s 2nd generation total synthesis of mycolactone A/B (1a,b). Reagents and conditions: a) 2,4,6...
Scheme 33: Blanchard’s synthesis of the 8-desmethylmycolactone core. Reagents and conditions: a) (i) TsCl, TEA...
Scheme 34: Altmann’s (partially unpublished) synthesis of the C20-hydroxylated mycolactone core. Reagents and ...
Scheme 35: Altmann’s and Blanchard’s approaches towards the 11-isopropyl-8-desmethylmycolactone core. Reagents...
Scheme 36: Blanchard’s synthesis of the saturated variant of the C11-isopropyl-8-desmethylmycolactone core. Re...
Scheme 37: Structure elucidation of photo-mycolactones generated from tetraenoate 224.
Scheme 38: Kishi’s synthesis of the linear precursor of the photo-mycolactone B1 lower side chain. Reagents an...
Scheme 39: Kishi’s synthesis of the photo-mycolactone B1 lower side chain. Reagents and conditions: a) LiTMP, ...
Scheme 40: Kishi’s synthesis of a stabilized lower mycolactone side chain. Reagents and conditions: a) (i) TBD...
Scheme 41: Blanchard’s variation of the C12’,C13’,C15’ stereocluster. Reagents and conditions: a) (i) DIBAL-H,...
Scheme 42: Blanchard’s synthesis of aromatic mycolactone polyenoate side chain analogs. Reagents and condition...
Scheme 43: Small’s partial synthesis of a BODIPY-labeled mycolactone derivative and Demangel’s partial synthes...
Scheme 44: Blanchard’s synthesis of the BODIPY-labeled 8-desmethylmycolactones. Reagents and conditions: a) (i...
Scheme 45: Altmann’s synthesis of biotinylated mycolactones. Reagents and conditions: a) (i) CDI, THF, rt, 2 d...
Figure 9: Kishi’s elongated n-butyl carbamoyl mycolactone A/B analog.
A novel approach to oxoisoaporphine alkaloids via regioselective metalation of alkoxy isoquinolines
- Benedikt C. Melzer and
- Franz Bracher
Beilstein J. Org. Chem. 2017, 13, 1564–1571, doi:10.3762/bjoc.13.156
- the synthesis of the alkaloid bianfugecine (6, Scheme 4), which contains only one methoxy group at ring B. Until now, only one partial synthesis of this alkaloid is described in the literature. Kunitomo et al. [30] obtained alkaloid 6 by hydrogenolytic demethoxylation of alkaloid menisporphine (2
Graphical Abstract
Figure 1: Prominent oxoaporphine and oxoisoaporphine alkaloids: liriodenine (1), menisporphine (2), dauriporp...
Scheme 1: Previously reported [7,17] and new approach to oxoisoaporphine alkaloids.
Scheme 2: Synthesis of iodinated isoquinolines 8a–c from alkoxy-substituted isoquinolines 7a–c.
Scheme 3: Synthesis of methyl 2-(isoquinolin-1-yl)benzoates 10a–c from 1-iodoisoquinolines 8a–c.
Scheme 4: Synthesis of the alkaloids 6-O-demethylmenisporphine (4), dauriporphinoline (5), and bianfugecine (6...
Scheme 5: Attempted synthesis of bianfugecine (6) via directed remote metalation and subsequent trapping of t...
Scheme 6: Outcome of a D2O quenching experiment after metalation of amide 12.
Scheme 7: Synthesis of 1-arylnaphthalene analogues 15 and 16.
Scheme 8: Outcome of a D2O quenching experiment after metalation of amide 16 with LDA.
Scheme 9: Synthesis of the alkaloids menisporphine (2) and dauriporphine (3) by O-methylation of the alkaloid...
Enduracididine, a rare amino acid component of peptide antibiotics: Natural products and synthesis
- Darcy J. Atkinson,
- Briar J. Naysmith,
- Daniel P. Furkert and
- Margaret A. Brimble
Beilstein J. Org. Chem. 2016, 12, 2325–2342, doi:10.3762/bjoc.12.226
- , MIC = 15.6 μg/mL) but only weakly active against all other bacteria tested. The structure was confirmed through degradation and partial synthesis [29][30]. Minosaminomycin (9) inhibits protein synthesis in E. coli more effectively than the related antibiotic kasugamycin (10), however, a different
Graphical Abstract
Figure 1: Structures of the enduracididine family of amino acids (1–6).
Figure 2: Enduracidin A (7) and B (8).
Figure 3: Minosaminomycin (9) and related antibiotic kasugamycin (10).
Figure 4: Enduracididine-containing compound 11 identified in a cytotoxic extract of Leptoclinides dubius [32].
Figure 5: Mannopeptimycins α–ε (12–16).
Figure 6: Regions of the mannopeptimycin structure investigated in structure–activity relationship investigat...
Figure 7: Teixobactin (17).
Scheme 1: Proposed biosynthesis of L-enduracididine (1) and L-β-hydroxyenduracididine (5).
Scheme 2: Synthesis of enduracididine (1) by Shiba et al.
Scheme 3: Synthesis of protected enduracididine diastereomers 31 and 32.
Scheme 4: Synthesis of the C-2 azido diastereomers 36 and 37.
Scheme 5: Synthesis of 2-azido-β-hydroxyenduracididine derivatives 38 and 39.
Scheme 6: Synthesis of protected β-hydroxyenduracididine derivatives 40 and 41.
Scheme 7: Synthesis of C-2 diastereomeric amino acids 46 and 47.
Scheme 8: Synthesis of protected β-hydroxyenduracididines 51 and 52.
Scheme 9: General transformation of alkenes to cyclic sulfonamide 54 via aziridine intermediate 53.
Scheme 10: Synthesis of (±)-enduracididine (1) and (±)-allo-enduracididine (3).
Scheme 11: Synthesis of L-allo-enduracididine (3).
Scheme 12: Synthesis of protected L-allo-enduracididine 63.
Scheme 13: Synthesis of β-hydroxyenduracididine derivative 69.
Scheme 14: Synthesis of minosaminomycin (9).
Scheme 15: Retrosynthetic analysis of mannopeptimycin aglycone (77).
Scheme 16: Synthesis of protected amino acids 87 and 88.
Scheme 17: Synthesis of mannopeptimycin aglycone (77).
Scheme 18: Synthesis of N-mannosylation model guanidine 92 and attempted synthesis of benzyl protected mannosy...
Scheme 19: Synthesis of benzyl protected mannosyl D-β-hydroxyenduracididine 97.
Scheme 20: Synthesis of L-β-hydroxyenduracididine 98.
Scheme 21: Total synthesis of mannopeptimycin α (12) and β (13).
Scheme 22: Synthesis of protected L-allo-enduracididine 102.
Scheme 23: The solid phase synthesis of teixobactin (17).
Scheme 24: Retrosynthesis of the macrocyclic core 109 of teixobactin (17).
Scheme 25: Synthesis of macrocycle 117.
An efficient partial synthesis of 4′-O-methylquercetin via regioselective protection and alkylation of quercetin
- Nian-Guang Li,
- Zhi-Hao Shi,
- Yu-Ping Tang,
- Jian-Ping Yang and
- Jin-Ao Duan
Beilstein J. Org. Chem. 2009, 5, No. 60, doi:10.3762/bjoc.5.60
- selective protection of the catechol group with dichlorodiphenylmethane in diphenyl ether as solvent and on the selective protection of the hydroxyl groups at positions 3 and 7 with chloromethyl ether. Keywords: alkylation; high yield; 4′-O-methylquercetin; partial synthesis; regioselective protection
- partial synthesis from quercetin (1) and relies on successive and selective protection of the different quercetin phenolic functions. Initially, we decided to adopt an alternative strategy which relies upon a selective protection of the catechol ring to make the later selective methylation easier. Hydroxy
- conclusion, we have succeeded in devising a partial synthesis of 4′-O-methylquercetin (tamarixetin) from quercetin in high yield. The strategy relies on the selective protection of the catechol group with dichlorodiphenylmethane at 175 °C using diphenyl ether as solvent and on the selective protection of the
Graphical Abstract
Figure 1: Structures of quercetin and methylated metabolites.
Scheme 1: Synthesis of 4′-O-methylquercetin (2, tamarixetin). a) Ph2CCl2, Ph2O, 175 °C, 30 min, 86%; b) MOMCl...
Figure 2: ROESY correlations of compound 2.
