1,6‐Additionen an 3‐Methyl‐5‐methyliden‐2‐(5<i>H</i>)‐furanon‐Derivate

Wyss, Heinz; Révész, Láśzló; Scheffold, Rolf

doi:10.1002/hlca.19810640733

Cited by 10 publications

(5 citation statements)

References 20 publications

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“…MS (ESI): [M+H] + calculated for C 9 H 10 O 2 H = 151.08, found 151.00. Spectral data were in accordance with those reported in the literature …”

Section: Methodssupporting

confidence: 90%

“…For the synthesis of all tonkafuranone‐related compounds in this paper we used the general strategy described earlier, involving an aldol condensation and lactone formation in a one‐pot procedure …”

Section: Resultsmentioning

confidence: 99%

“…For the synthesis of the 6‐ and 3‐unsubstituted analogue 2 (Scheme ), we started from cyclohexanone ( 8 ) and glyoxylic acid ( 9 ) and performed the aldol condensation and lactonization in concentrated phosphoric acid, similar to the conditions described in the literature . The methyl‐free achiral product 2 was obtained after removal of the phosphoric acid by neutralization, followed by flash column chromatography on silica gel.…”

Section: Resultsmentioning

confidence: 99%

“…According to the GSP, 3 was synthesized from cyclohexanone ( 8 ) (2 mL, 1.896 g, 36.6 mmol) and pyruvic acid ( 10 ) (3.3 mL, 4.190 g, 47.58 mmol, 1.3 equivalents) after heating to 120 °C for 3 h. Flash column chromatography (PE/EA = 9/1 R f = 0.07) yielded 3 as a colourless oil (2473 mg, 16.47 mmol, 45%) …”

Section: Methodsmentioning

confidence: 99%

“…For 5a / 5b and 6a / 6b , which are minor side products, even the racemates are novel, but they were not considered for biological evaluations because of the small quantities available. All other compounds, namely 2 , 3 , and the racemates 4a / 4b and 1a / 1b , have already been described in the literature . For comparison, see the related structure of patulin ( 7 ).…”

Section: Introductionmentioning

confidence: 99%

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(R)‐Tonkafuranone and related compounds: Improved synthesis, stereochemical purity in nature, and bioactivities of the pure enantiomers

Hoffmann

Sita

Kleider

et al. 2019

Flavour & Fragrance J

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Dehydromenthofurolactone (tonkafuranone) and other bicyclic lactones are common flavour compounds and can be found in a variety of plants. Herein, we present an improved synthesis of the natural product and a series of close analogues, in combination with efficient purification methods for simple preparation from cheap and easily accessible chemicals. A two‐step, one‐pot, reaction procedure, consisting of an aldol condensation step with concomitant lactonization, yields simplified analogues of the natural parent compound (R)‐tonkafuranone and its likewise natural (S)‐enantiomer, lacking one or two of its methyl groups, respectively. In the case of regioisomeric products, these were resolved by preparative high‐performance liquid chromatography, which, in the case of chiral, yet racemic products, was followed by preparative enantio‐resolution on a chiral phase, permitting the isolation of all four pure isomers from one synthetic step. Using the stereo‐analytical method developed, the enantiomeric purity of natural tonkafuranone occurring in Bursera graveolens was analysed and found to be ‘100:0’ in favour of the S‐enantiomer. The chiral, enantiomerically pure products were configurationally assigned by co‐elution, semi‐synthesis, and/or chiroptical methods. With the pure isomers obtained, specific cytotoxicities were tested in two cell lines as a measure for their reactivities towards cellular nucleophiles. Although the synthesized compounds differed in their cytotoxic potential in V79 cells, they exhibited a much smaller cytotoxic potential than the mutagenic α,β,γ,δ‐unsaturated lactone patulin. No toxicity towards murine hippocampal HT‐22 cells was observed at 50 μM. Thus, the molecular mechanism contributing to the high reactivity of patulin towards nucleophiles may not apply for tonkafuranone and structurally related compounds.

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“…MS (ESI): [M+H] + calculated for C 9 H 10 O 2 H = 151.08, found 151.00. Spectral data were in accordance with those reported in the literature …”

Section: Methodssupporting

confidence: 90%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%