Chemical transformations of abundant natural products. 3. Modifications of eremanthin leading to other naturally occurring guaianolides

Maçaira, Lélio A.; García, Maribel Osorio; Rabi, Jaime A.

doi:10.1021/jo00862a007

Cited by 20 publications

(9 citation statements)

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“…For the synthesis of model 10, previously described, 13 we used conditions v (Scheme 1). After the time of reaction, a product was isolated and then identified as isoeremanthine (10) by spectroscopy methods.…”

Section: Resultsmentioning

confidence: 99%

“…Continuing the research program about chemical transformations of eremanthine (1), whose initial results were published in a recent article, 8 in this paper we report the syntheses of 4(15)-dihydroeremanthine (8), 4(15),9(10)-tetrahydroeremanthine (9), isoeremanthine (10), allylic acetate Δ 1,10 (11), 1(R),10(R)-dihydromicheliolide (12) and 4α-hydroxy allylic acetate Δ 1,10 (13) and posterior reaction of lactonic fusion inversion on these derivatives ( Figure 3). It was evaluated in this study of lactonic inversion on eremanthine derivatives, the viability of obtaining guaianolides with cis lactonic fusion at the C6-C7 position and substances containing the structural requirements for subsequent study of biomimetic transformation of guaianolides into pseudoguaianolides.…”

Section: Introductionmentioning

confidence: 88%

“…The organic phases were dried with Na 2 SO 4 , filtered and evaporated under reduced pressure. Purification by column chromatography eluted with hexane and 10% EtOAc / hexane gave: Guaia-9,11 (13) Guai-11(13)-eno-4β(H),10β(H)-12,6α-lactone (9a); Guai-11(13)-eno-4β(H),10α(H)-12,6α-lactone (9b) and -eno-4α(H),10β(H)-12,6α-lactone (9c) (0.030 g, 84%) as a colourless oil. R f 0.76 (50% EtOAc / hexane).…”

Section: Guaia-911(13)-dieno-126α-lactone (8) and Guai-11(13)-eno-1mentioning

confidence: 99%

“…The crude product was purified by column chromatography of silica gel eluted with 80% EtOAc / hexane. It was obtained a colourless oil (0.067 g, 75%) identified by 1 Guaia-1(10), 4(15), 11(13)-trieno-9α-acetate-12,6α-lactone (11) and Guaia-1(10),11 (13)-dieno-4α-hydroxy,9α-acetate-12,6α-lactone (13) General procedure for preparation of allylic acetates 11 and 13…”

Section: Guaia-1(10)11(13)-dieno-4α9α-dihydroxy-126α-lactone (17)mentioning

confidence: 99%

“…Isoeremanthine (10) was previously synthesized from isomerization of double bond C4-C15 of eremanthine (1) to C3-C4 position and it would be obtained by the same procedure. 13 For the synthesis of allylic acetate 11 we planned to obtain it through an elimination step of iodohydrins 18-19, previously described, 14 by metal in acid medium to generate the respective products 16 and 11. 15 In the case of allylic alcohol 16, it would be made an additional stage of protection at the hydroxy group in C-9 position through an acetylation reaction for obtention of compound 11.…”

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Study of the inversion reaction of the lactonic fusion on eremanthine derivatives

Alves¹,

Fantini²

2007

J. Braz. Chem. Soc.

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As α-metileno-γ-lactonas 4(15)-diidroeremantina (8), 4(15),9(10)-tetraidroeremantina (9), isoeremantina (10), acetato alílico Δ 1,10 (11), 1(R),10(R)-diidromiqueliolido (12) e 4α-hidróxi acetato alílico Δ 1,10 (13) foram sintetizadas a partir do produto natural abundante eremantina (1). Essas substâncias foram submetidas à reação de hidrólise com KOH aquoso e os sais carboxílicos dessas lactonas tiveram suas hidroxilas ativadas na posição C-6, pela formação dos respectivos mesilatos (MsCl, Et 3 N, THF ou DMSO) para deslocamento nucleofílico efetuado pelo grupo carboxilato. A utilidade dessa metodologia foi investigada para a obtenção de guaianolidos com fusão lactônica cis na posição C6-C7 e para sintetizar um precursor para estudo posterior da transformação biomimética de guaianolidos em pseudoguaianolidos.The α-methylene-γ-lactones 4(15)-dihydroeremanthine (8), 4(15),9(10)-tetrahydroeremanthine (9), isoeremanthine (10), allylic acetate Δ 1,10 (11), 1(R),10(R)-dihydromicheliolide (12) and 4α-hydroxy allylic acetate Δ 1,10 (13) were synthesized from the abundant natural product eremanthine (1). These substances were submitted to hydrolysis reaction with aqueous KOH and the carboxylic salts of these lactones had their hydroxy groups activated at the C-6 position by formation of respective mesylates (MsCl, Et 3 N, THF or DMSO) which underwent further displacement by carboxylate group. The utility of this methodology was investigated in order to obtain guaianolides with cis lactonic fusion at the C6-C7 position and to synthesize a precursor for posterior study of the biomimetic transformation of guaianolides into pseudoguaianolides.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 88%

Section: Guaia-911(13)-dieno-126α-lactone (8) and Guai-11(13)-eno-1mentioning

confidence: 99%

Section: Guaia-1(10)11(13)-dieno-4α9α-dihydroxy-126α-lactone (17)mentioning

confidence: 99%

mentioning

confidence: 99%

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Study of the inversion reaction of the lactonic fusion on eremanthine derivatives

Alves¹,

Fantini²

2007

J. Braz. Chem. Soc.

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Secondary Metabolites of Plants from the Genus Saussurea: Chemistry and Biological Activity

Wang

Dong

et al. 2010

Chemistry & Biodiversity

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The Asteraceae family comprises ca. 1000 genera, mainly distributed in Asia and Europe. Saussurea DC., as the largest subgenus of this family, comprises ca. 400 species worldwide, of which ca. 300 species occur in China. Most plants in China grow wild in the alpine zone of the Qingzang Plateau and adjacent regions at elevations of 4000 m. Plants of the genus Saussurea (Asteraceae) are used in both traditional Chinese folk medicine and Tibet folklore medicine, since they are efficacious in relieving internal heat or fever, harmonizing menstruation, invigorating blood circulation, stopping bleeding, alleviating pain, increasing energy, and curing rheumatic arthritis. A large number of biologically active compounds have been isolated from this genus. This review shows the chemotaxonomy of these compounds (215 compounds) such as sesquiterpenoids (101 compounds), flavonoids (19 compounds), phytosterols (15 compounds), triterpenoids (25 compounds), lignans (32 compounds), phenolics (23 compounds), and chlorophylls (11 compounds). Biological activities (anti-inflammatory, anticancer, antitumor, hepatoprotective, anti-ulcer, cholagogic, immunosuppressive, spasmolytic, antimicrobial, antiparasitic, antifeedant, CNS depressant, antioxidant, etc.) of these compounds, including structure-activity relationships, are also discussed.

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ChemInform Abstract: CHEMICAL TRANSFORMATIONS OF ABUNDANT NATURAL PRODUCTS. 3. MODIFICATIONS OF EREMANTHIN LEADING TO OTHER NATURALLY OCCURRING GUAIANOLIDES

Maçaira¹,

García²,

Rabi³

1978

Chemischer Informationsdienst

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Chemical transformations of abundant natural products. 3. Modifications of eremanthin leading to other naturally occurring guaianolides

Cited by 20 publications

References 2 publications

Study of the inversion reaction of the lactonic fusion on eremanthine derivatives

Study of the inversion reaction of the lactonic fusion on eremanthine derivatives

Secondary Metabolites of Plants from the Genus Saussurea: Chemistry and Biological Activity

ChemInform Abstract: CHEMICAL TRANSFORMATIONS OF ABUNDANT NATURAL PRODUCTS. 3. MODIFICATIONS OF EREMANTHIN LEADING TO OTHER NATURALLY OCCURRING GUAIANOLIDES

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