Oxidation of α,β-un saturated aldehydes

Bal, Balkrishna S.; Childers, Wayne E.; Pinnick, Harold W.

doi:10.1016/s0040-4020(01)97963-3

Cited by 1,180 publications

(710 citation statements)

References 19 publications

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“…12 Therefore, the mixture of 2E and 2Z isomers was first converted to the corresponding E,Z-cyanohydrin mixture and then oxidized to the corresponding acyl cyanides with MnO 2 . Methanolysis gave a mixture of the 3E and 3Z monomethyl esters.…”

Section: Resultsmentioning

confidence: 99%

In Vitro Biotransformations of Isocupressic Acid by Cow Rumen Preparations: Formation of Agathic and Dihydroagathic Acids

Lin

Short²,

Ford

et al. 1998

J. Nat. Prod.

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Isocupressic acid [15-hydroxylabda-8(17), 13E-dien-19-oic acid] (1) was incubated under anaerobic conditions for 48 h in an in vitro ruminal fluid mixture and was transformed into two metabolites. The two metabolites were identified by GC/MS as agathic acid [labda-8(17),13(E)-diene-15,19-dioic acid] (4E) and dihydroagathic acid [labda-8(17)-ene-15,19-dioic acid] (6). Metabolite identities were confirmed by chemical conversions of isocupressic acid (1) and imbricataloic acid (5) into 4E and 6, respectively. Structures of synthetic metabolites were confirmed by 1 H and 13 C NMR, specific rotation, GC/MS, and high-resolution mass spectrometry. Plasma obtained from cows that were fed Ponderosa pine needles contained (13R,S)-dihydroagathic acid (6) but not isocupressic acid (1) or 4E. The results suggest that isocupressic acid (1) is metabolically oxidized to agathic acid (4E), subsequently reduced to (13R,S)-dihydroagathic acid (6) in the rumen, and then absorbed into the bloodstream of cattle.Premature parturition in cattle due to the ingestion of Ponderosa pine [Pinus ponderosa Dougl. ex Laws (Pinaceae)] needles is a major economic problem in the Western United States and Canada. 1 Previous investigations have attempted to isolate and characterize the compounds in P. ponderosa responsible for pine needle abortion. A new class of vasoactive lipids 2 and isocupressic acid 3 [15-hydroxylabda-8(17),13(E)-dien-19-oic acid] (1) were identified as possible causative agents in pine needle abortion in pregnant cows. However, the effects of pine needle ingestion on domestic ruminants such as cattle, Bison, sheep, and goats are variable with regard to the parturition response and/or the presence of vasoconstrictive principles present in plasma samples. [4][5][6] The species differences observed in the pine needle abortion phenomenon may result from variability in the differences in digestive systems among species, from differences of possible metabolic transformations of ingested precursor abortifacient compounds, or from a combination of these factors.Ruminants, including cattle, possess a four-compartment stomach. The largest compartment, the rumen, contains a mixed and variable population of symbiotic microorganisms effective in fermenting fibrous feedstuffs into nutrients usable by the host animal. The environment in the rumen is generally anaerobic, neutral to slightly acidic (between pH 5.5-7.0), and at a temperature between 38 and 41°C. During digestion, the rumen microflora cooperatively catalyze enzymatic transformations of nutrients, fiber, and other ingested substances. Digested materials ultimately pass into the bloodstream of the ruminant animal where they are broadly distributed, bound, further metabolized, and ultimately excreted.The mechanism whereby pine-needle ingestion induces abortion in cattle has been shown to involve a reduction in blood flow to the gravid uterus, resulting in a marked and progressive decrease in nutrients and oxygen available to the fetal calf. 4,7 This is consistent with the observa...

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Section: Resultsmentioning

confidence: 99%

In Vitro Biotransformations of Isocupressic Acid by Cow Rumen Preparations: Formation of Agathic and Dihydroagathic Acids

Lin

Short²,

Ford

et al. 1998

J. Nat. Prod.

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“…55 Scheme 25 Our new second-generation pathway to dipeptide 111. 55 Having served its purpose in installing this feature, the O-isopropylidene group was detached from 176 and the liberated 1,2-diol 177 oxidatively cleaved to the acid by successive lead tetraacetate glycol fission and Pinnick oxidation 67 which gave the acid 179. The latter thereafter had its O-benzyl ether group detached by catalytic hydrogenolysis and, following this, potassium carbonate promoted esterification of 180 with allyl iodide furnished ester 181 ready for O-triflation and S N 2 displacement with O-benzylhydroxylamine.…”

Section: New Insights Into the Mechanism Of Antitumour Action Of A83586cmentioning

confidence: 99%

Total synthesis of (+)-A83586C, (+)-kettapeptin and (+)-azinothricin: powerful new inhibitors of β-catenin/TCF4- and E2F-mediated gene transcription

2010

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Section: Resultsmentioning

confidence: 99%

“…First, alcohols 42-44 were reacted with TPAP to give the aldehydes 45, 46 and 47 in 98, 85 and 95% yields, respectively. Finally, the aldehydes 45-47 were oxidized according to Pinnick conditions 21 to give acids 48, 49 and 50, in 92, 80 and 85% yields (Scheme 7).…”

Section: Resultsmentioning

confidence: 99%

“…20 Oxidation of the aldehydes with sodium chlorite provided the acid 20a/b, in 90% yield (Scheme 4). 13,21 After chromatographic purification the minor diastereoisomer (20b) was no longer detected.Acid 20a was then submitted to a Curtius rearrangement in order to incorporate the nitrogen atom of the lactam unit present in the skeleton of the Amaryllidaceae alkaloids. 22 The rearrangement was carried out in a one pot sequence to furnish the carbamate 24.…”

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Studies toward the synthesis of Amaryllidaceae alkaloids from Morita-Baylis-Hillman adducts: a straightforward synthesis of functionalized dihydroisoquinolin-5(6H)-one core

Lopes¹,

Coelho²

2007

J. Braz. Chem. Soc.

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Descrevemos neste trabalho, os resultados de um estudo que teve como objetivo a síntese de esqueletos de carbono altamente funcionalizados de alcalóides de plantas da família das Amaryllidaceae. A partir de adutos de Morita-Baylis-Hillman, descrevemos a síntese total do núcleo diidroisoquinolin-5(6H)-ona funcionalizado, que é a parte inferior da estrutura de vários alcalóides dessa classe. Essa substância pode ser um intermediário útil e valioso para a síntese total dos alcalóides isolados de plantas da família Amaryllidaceae.We disclose herein our results concerning a study aiming at the synthesis of the highly substituted carbon skeleton of alkaloids isolated from plants of the Amaryllidaceae family. The total synthesis of the functionalized dihydroisoquinolin-5(6H)-one core, which is the bottom part of the structure of alkaloids isolated from this botanic family, is described, using MoritaBaylis-Hillman adducts as substrate. This compound should be a useful and valuable intermediate for the total synthesis of alkaloids isolated from Amaryllidaceae. Keywords: Morita-Baylis-Hillman adducts, Amaryllidaceae, dihydroisoquinolinones IntroductionPlants from the Amaryllidaceae family are spread all over the world and due to its pharmacological relevance some representatives of this botanic family are known by humans since antiquity. 1 Among the chemical constituents present in these plants, the alkaloids are the most important and, normally, they are responsible for the biological activities exhibited. As a matter of fact, the biological importance of the plants from this family led to an intense phytochemical research activity, which culminated with the isolation and chemical characterization of several structurally different classes of alkaloids. 2 Galanthamine (1), 3 pancratistatin (2), 4 narciclasine (3), 5 hippadine (4), 6 anhydrolycorinone (5), 6,7 and plicamine (6) 8 are examples that clearly show the structurally rich diversity of these alkaloids (Figure 1). Besides structural complexity, these alkaloids exhibit different biological activities. Galantamine (1), for example, is a specific, competitive and reversible acetyl cholinesterase inhibitor, being used in the clinical treatment of Alzheimer disease. 3 Pancratistatin (2), narciclasine (3), hippadine (4) and anhydrolycorinone (5) exhibit antiproliferative activity. 9,10 The highly sophisticated substitution pattern of the carbon skeleton of these alkaloids, associated with their relevant biological and pharmacological significance, induced the interest of synthetic organic chemists in establishing strategies aiming at their total syntheses, in both racemic and asymmetric versions. The results of these efforts can be easily measured by the countless reports available in the literature describing successful syntheses of several types of alkaloids isolated from Amaryllidaceae. 11 Particularly, the alkaloids which are structurally related to pantacristatin (2) were synthesized successfully by using the strategy of joining the two suitably substituted fragm...

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Oxidation of α,β-un saturated aldehydes

Cited by 1,180 publications

References 19 publications

In Vitro Biotransformations of Isocupressic Acid by Cow Rumen Preparations: Formation of Agathic and Dihydroagathic Acids

In Vitro Biotransformations of Isocupressic Acid by Cow Rumen Preparations: Formation of Agathic and Dihydroagathic Acids

Total synthesis of (+)-A83586C, (+)-kettapeptin and (+)-azinothricin: powerful new inhibitors of β-catenin/TCF4- and E2F-mediated gene transcription

Studies toward the synthesis of Amaryllidaceae alkaloids from Morita-Baylis-Hillman adducts: a straightforward synthesis of functionalized dihydroisoquinolin-5(6H)-one core

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