575. Taxine. Part I. Isolation studies and the functional groups of O-cinnamoyltaxicin-I

Baxter, J. N.; Lythgoe, B.; Scales, B.; Scrowston, R. M.; Trippett, S.

doi:10.1039/jr9620002964

Cited by 30 publications

(12 citation statements)

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“…The formation of the cinnamates 10 is also synthetically possible by quaternization of the amino group with MeI followed by treatment with K 2 CO 3 in a 1:1 mixture of EtOH and H 2 O. ,, A 4.5-h treatment with 6.5 equiv of K 2 CO 3 resulted in the complete hydrolysis of all the acetate groups originally present in 10 , yielding two products with retention times around 23 min. These mild conditions for acetate hydrolysis are superior for the use of sodium methoxide .…”

Section: Resultsmentioning

confidence: 99%

“…The solution was then extracted with four 300-mL portions of CHCl 3 , and the combined organic layers were dried (Na 2 SO 4 ), filtered, and evaporated under reduced pressure to yield 3-4.5 g of crude taxine. 17,20 Isolation of the Taxines. The minor taxines 2, 4, 5, and 6 were separated from the major taxines 1 and 3 by column chromatography over neutral alumina (activity grade I) with EtOAc as eluent.…”

Section: Methodsmentioning

confidence: 99%

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Identification of Six Taxine Alkaloids from Taxus baccata Needles

Jenniskens¹,

Rozendaal²,

Beek³

et al. 1996

J. Nat. Prod.

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Six taxine alkaloids were isolated from Taxus baccata needles and partially separated. An HPLC method for the analysis of the taxine fraction was developed. By NMR and deamination/hydrolysis studies it was established that the taxine fraction consisted mostly of taxicin-I and taxicin-II derivatives in a variable ratio. Four of the six taxine alkaloids isolated have not been reported before. All of the alkaloids were found to be unstable under neutral and basic conditions, and some of them were very easily interconverted.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Identification of Six Taxine Alkaloids from Taxus baccata Needles

Jenniskens¹,

Rozendaal²,

Beek³

et al. 1996

J. Nat. Prod.

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“…He would start at the beginning in a 'bottom up' approach, while I would start with taxol and study its chemistry in a 'top down' approach. Since we did not have a supply of taxol, I decided to begin by looking at the possible conversion of O-cinnamoyltaxicin I triacetate (6), available by Lythgoe's procedure from taxine B (7) 25 into taxol or taxol-like compounds. I isolated about 100 mg of crude taxine B from yew bushes growing on the Virginia Tech campus, converted it into 6, and did some preliminary work on forming the oxetane ring.…”

Section: Early Studiesmentioning

confidence: 99%

Taxol, a molecule for all seasons

2001

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“…We have incomplete knowledge about the poisonous nature of yew. Former investigators found that the toxic properties of yew resulted from the alkaloid taxine (4,5) and it caused cardiac arrest in diastole (1). It has been shown that taxine was a mixture of alkaloids.…”

Section: Introductionmentioning

confidence: 99%

Negative Chronotropic and Atrioventricular Blocking Effects of Taxine on Isolated Frog Heart and Its Acute Toxicity in Mice

Tekol¹

1985

Planta Med

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The alkaloid mixture of yew ( TAXUS BACCATA) was converted to sulphate salt and this salt form of the drug was used throughout the experiments. The median lethal doses (LD50) and their 19/20 confidence limits of two samples of the drug, the freshly prepared and the stored taxine sulphate, were determined on mice (s. c.) and found as 12.96 (11.37-14.77) and 13.09 (11.73-14.61) mg/kg, respectively. There was no significant difference between these values. Results show that taxine in salt form can be preserved for long periods without loosing its properties. The cardiac actions of the drug (10-100 microg/ml) were determined on isolated frog heart. It was found that the drug slows both atrial and ventricular rate dose-dependently, however, the rate-depressing effect was more prominent on the ventricle, e.g., in the highest concentration, the observed percent changes in cardiac rate (mean +/- S.E.M.) were 38.29 +/- 4.13 for atrium and 1.71 +/- 0.80 for ventricle, indicating that the atrioventricular conduction is more susceptible to the drug. The effect of the drug on the heart could be removed partially by washing. At the end of this procedure, the atrial and ventricular rates reached 56.63 +/- 5.44 and 51.35 +/- 5.54 that of control rates, respectively. From these findings and those observed by previous authors, it is deduced that the actions of taxine on heart might result from its Ca (2+) antagonizing properties, but electrophysiological studies are necessary for a definitive conclusion.

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575. Taxine. Part I. Isolation studies and the functional groups of O-cinnamoyltaxicin-I

Cited by 30 publications

References 0 publications

Identification of Six Taxine Alkaloids from Taxus baccata Needles

Identification of Six Taxine Alkaloids from Taxus baccata Needles

Taxol, a molecule for all seasons

Negative Chronotropic and Atrioventricular Blocking Effects of Taxine on Isolated Frog Heart and Its Acute Toxicity in Mice

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