The Synthesis of 5-Hydroxy-3-methylnaphtho[2,3-c]furan-4,9-dione and 5,8-Dihydroxy-1-methylnaphtho[2,3-c]furan-4,9-dione

Piggott, Matthew; Wege, Dieter

doi:10.1071/ch02253

Cited by 17 publications

(23 citation statements)

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“…As shown in Scheme 2, allylic alcohol 11 was prepared from (4-methoxyphenoxy)-acetaldehyde ( 9 )20 via a two-step HWE/reduction protocol 19. Previously, because it is difficult to achieve high E -selectivity by the HWE olefination reaction, ( E )-α,β-unsaturated ester 10 was obtained by nucleophilic substitution of alkyl 4-bromocrotonate with 4-methoxyphenol 21.…”

Section: Resultsmentioning

confidence: 99%

Asymmetric Synthesis of d-ribo-Phytosphingosine from 1-Tetradecyne and (4-Methoxyphenoxy)acetaldehyde

2010

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An asymmetric synthesis of D-ribo-phytosphingosine (1) was achieved by utilizing the ProPhenolcatalyzed alkynylation of aldehyde 8 to afford allylic propargylic alcohol (S)-6 followed by asymmetric epoxidation and opening of propargylic epoxy alcohol anti-5 with NaN 3 /NH 4 Cl. Deprotection and reduction of the resulting acyclic azide 3 then gave 1. Alkyne-azide 3 was subjected to an intramolecular click reaction, generating a bicyclic triazole, which was found to have unexpected vicinal coupling constants. Application of the advanced Mosher method verified the configurations of the three contiguous stereogenic centers of 1. An alkynyl-azide analogue of 1, which may be useful as a glycosyl acceptor in the synthesis of α-galactosylceramide derivatives, was also readily prepared by this route.

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Section: Resultsmentioning

confidence: 99%

Asymmetric Synthesis of d-ribo-Phytosphingosine from 1-Tetradecyne and (4-Methoxyphenoxy)acetaldehyde

2010

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“…Our data are presented in Table 1. The 13 C NMR data of 7 have been reported by Piggot and Wege without any assignment [13]. Our results from the complete assignment of all protons and carbons achieved by 1D and 2D NMR experiments are presented in Table 1.…”

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confidence: 55%

“…The anthraquinones 2 and 4 and the naphthalene compounds 3 and 6 are new for the genus Asphodeline. The naphthoquinone 7 is a known synthetic compound [13]. However, this is the first report on its natural occurrence and on the presence of naphthoquinones in Asphodeline species.…”

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confidence: 91%

Anthraquinone, naphthalene, and naphthoquinone components of Asphodeline lutea

et al. 2010

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The genus Asphodeline belongs to the family Asphodelaceae, subfamily Asphodeloideae. The 1,8-dihydroxyanthraquinones based on a chrysophanol unit are characteristic compounds of this subfamily. Anthraquinones, flavonoids, oxepines, and sesquiterpene lactones have been reported to occur in the genus Asphodeline [1][2][3][4].Asphodeline lutea is a perennial plant growing in the Mediterranian region. The only report found on this plant species reveals the presence of 1,8-dihydroxyanthraquinones, flavonoids, and a chlorogenic acid [5]. Data on the biological activity and the medicinal use of A. lutea are not available. However, the edible use of its roots, shoots, and flowers has been reported [6]. The ancient Greeks roasted the roots like potatoes and ate them with salt and oil or mashed them with figs. The raw fresh flowers are very decorative and a tasty addition to salad, while the young shoots are eaten cooked.The roots of A. lutea were collected in June 2005 near the town of Pernik, Bulgaria. The dried roots (0.70 kg) of A. lutea were extracted with methanol (3 times u 24 h u 2.7 L) at room temperature, then concentrated in vacuum to give a crude methanol extract (22.0 g). Solvent-solvent partition of this extract using petroleum ether, chloroform, and ethylacetate afforded the corresponding petroleum ether (4.3 g), chloroform (5.2 g), and ethylacetate (0.5 g) extracts and an aqueous residue (15.2 g).The petroleum ether extract was subjected to liquid vacuum chromatography (LVC) on silica gel using PE, PE-CHCl 3 (3:1o1:3), CHCl 3 , CHCl 3 -EtOAc (1:1), and EtOAc to give fractions F1-F6. Silica gel CC and repeated pTLC of F6 afforded compounds 1 (2 mg), 2 (6 mg), 3 (7 mg), 4 (3 mg), and 5 (1 mg).LVC of the chloroform extract with PE-CHCl 3 (20:1o1:1) and CHCl 3 gave fractions F1-F4. From F4 after silica gel CC and pTLC separation components 6 (4 mg), 7 (2 mg), 5 (5 mg), and 8 (6 mg) were isolated.The chemical structures of the isolated compounds were determined by a combination of spectral methods (UV, IR, 1D and 2D NMR, and MS) and comparison with literature data as chrysophanol (1) [7], 1,5,8-trihydroxy-3-methylanthraquinone (2) [8], 2-acetyl-1,8-dimethoxy-3-methylnaphthalene (3) [9, 10], 1-hydroxy-8-methoxy-3-methylanthraquinone (4) [11], asphodeline (5) [12], 2-acetyl-1-hydroxy-8-methoxy-3-methylnaphthalene (6) [9, 10], 2-acetyl-8-methoxy-3methylnaphthoquinone (7) [13], and 1,1c,8,8c,10-pentahydroxy-3,3c-dimethyl-10,7c-bianthracene-9,9c,10c-trione (8) [14]. Of them only chrysophanol (1) and asphodeline (5) have been reported to occur in A. lutea [5]. The anthraquinones 2 and 4 and the naphthalene compounds 3 and 6 are new for the genus Asphodeline. The naphthoquinone 7 is a known synthetic compound [13]. However, this is the first report on its natural occurrence and on the presence of naphthoquinones in Asphodeline species.A full assignment of all protons and carbons in the molecule of 3 was undertaken by detailed 1D and 2D NMR measurements because of the discrepancy between the assignments of C signals in ...

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“…Continuing with this analysis, removal of the epoxide moiety in 23 leads to a homoallylic alcohol, 22 which upon application of a Brown crotylation retron, yields known aldehyde 25 . 23 …”

Section: Resultsmentioning

confidence: 99%

(+)-Sorangicin A: evolution of a viable synthetic strategy

et al. 2011

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An effective, asymmetric total synthesis of the antibiotic (+)-sorangicin A (1) has been achieved. Central to this venture was the development of first and second generation syntheses of the signature dioxabicyclo[3.2.1]octane core, the first featuring chemo- and stereoselective epoxide ring openings facilitated by a Co2(CO)6-alkyne complex, the second involving a KHMDS-promoted epoxide ring formation/opening cascade. Additional highlights include effective construction of the dihydro- and tetrahydropyran ring systems, respectively via a stereoselective conjugate addition/α-oxygenation protocol and a thioketalization/hydrostannane reduction sequence. Late-stage achievements entailed two Julia–Kociénski olefinations to unite three advanced fragments with high E-stereoselectivity, followed by a modified Stille protocol to introduce the Z,Z,E trienoate moiety, thereby completing the carbon skeleton. Mukaiyama macrolactonization, followed by carefully orchestrated Lewis and protic acid-promoted deprotections that suppressed isomerization and/or destruction of the sensitive (Z,Z,E)-trienoate linkage completed the first, and to date only, total synthesis of (+)-sorangicin A (1)

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The Synthesis of 5-Hydroxy-3-methylnaphtho[2,3-c]furan-4,9-dione and 5,8-Dihydroxy-1-methylnaphtho[2,3-c]furan-4,9-dione

Cited by 17 publications

References 1 publication

Asymmetric Synthesis of d-ribo-Phytosphingosine from 1-Tetradecyne and (4-Methoxyphenoxy)acetaldehyde

Asymmetric Synthesis of d-ribo-Phytosphingosine from 1-Tetradecyne and (4-Methoxyphenoxy)acetaldehyde

Anthraquinone, naphthalene, and naphthoquinone components of Asphodeline lutea

(+)-Sorangicin A: evolution of a viable synthetic strategy

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