Natural sesquiterpenoids

Fraga, Braulio M.

doi:10.1039/b507870a

Cited by 61 publications

(27 citation statements)

References 343 publications

(287 reference statements)

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“…Previous studies on the lactonic fusion inversion of eremanthine (1) led to the synthesis of 6-epi-eremanthine (7) (see Figure 3) that was shown unstable. Such instability was attributed to conformational effects of hydroazulene system 9 that resulted in a high tension at the lactonic ring, evidenced through its infrared spectral data.…”

Section: Strategies For the Syntheses Of Eremanthine Derivativesmentioning

confidence: 99%

“…Such procedure was idealized in order to facilitate the isolation of product since the use of DMF, with high ebullition point, turned more difficult the purification process of the elimination products. The starting material initially used on the methanol elimination with the new solvent (CH 3 CN) was the methoxy derivative 14, due to the easy access from eremanthine (1) in just a stage. The reaction was executed at the conditions described in Scheme 7.…”

Section: Reactions Of the Lactonic Fusion Inversion On Eremanthine Dementioning

confidence: 99%

“…CHCl 3 (21 mL) was added and the mixture, kept in the dark, was vigorously stirred at room temperature for 24 h. The organic layer was separated and then used in the epoxidation reaction. Epoxidation of eremanthine (1). Eremanthine (1) (0.300 g, 1.302 mmol) was dissolved in a solution of AcO 2 H/CHCl 3 (21 mL), prepared as described above.…”

Section: Isoeremanthine (10)mentioning

confidence: 99%

“…These substances are the guaianolides and their biogenetical derivatives, the pseudoguaianolides. 1 Guaianolides have the skeleton of bicyclo [5.3.0]decane, characteristic of sesquiterpenes denominated guaianes, to which was inserted at positions C-6 and C-7 or C-7 and C-8 a γ-lactonic ring containing in C-11 a methyl group or a vinylic methylene and at positions C-4 and C-10 methyl groups or vinylic methylenes. As examples of guaianolides we can cite eremanthine (1), a schistosomicidal substance isolated from Brazilian compositae Eremanthus elaeagnus and Vanillosmopsis erythropappa, 2 and gaillardin (2) 3 ( Figure 1).…”

Section: Introductionmentioning

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: 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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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: Strategies For the Syntheses Of Eremanthine Derivativesmentioning

confidence: 99%

Section: Reactions Of the Lactonic Fusion Inversion On Eremanthine Dementioning

confidence: 99%

Section: Isoeremanthine (10)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

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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Biosynthetic Pathway Engineering Strategies

Schmidt‐Dannert

Pisarchik

2008

Protein Engineering Handbook

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Intramolecular Cyclization of 2‐Alkynylphenylcarbonyls With a Pendant Double Bond under Copper Catalysis: A General Approach to Norabietane Core Structure

Kang

Lee

et al. 2022

Asian J Org Chem

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Synthetic routes leading to [6,6,6]‐tricyclic compounds were reported using metal catalysts from ene‐yne‐aldehydes in our group. Based on this result, the synthesis of various [6,6,6]‐tricyclic compounds is reported using transition metal‐catalyzed cyclization from enyne‐carbonyl substrates containing H, Me, Ph, OMe, CO2Me, and CO2i‐Pr groups. Tricyclic compounds containing the CO2Me group would be the prospective precursors of the natural product Lepenine.

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Natural sesquiterpenoids

Abstract: This review covers the isolation, structural determination, synthesis and chemical and microbiological transformations of natural sesquiterpenoids. The literature from January to December 2005 is reviewed,and 386 references are cited.

Cited by 61 publications

References 343 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

Biosynthetic Pathway Engineering Strategies

Intramolecular Cyclization of 2‐Alkynylphenylcarbonyls With a Pendant Double Bond under Copper Catalysis: A General Approach to Norabietane Core Structure

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