Abietane and icetexane diterpenoids from Salvia ballotaeflora and Salvia axillaris

Esquivel, Baldomero; Calderón, JoséS.; Flores, Edgar; Sánchez, Ana-Adela; Rivera, Rosaura Rosas

doi:10.1016/s0031-9422(97)00310-5

Cited by 24 publications

(31 citation statements)

References 17 publications

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“…Samples of icetexone ( 1 ) and conacytone ( 3 ) were available from previous studies, while icetexone acetate ( 2 ) and conacytone triacetate ( 4 ) were obtained by acetylation of the natural products using standard reaction conditions.…”

Section: Methodsmentioning

confidence: 99%

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Absolute configuration of the diterpenoids icetexone and conacytone from Salvia ballotaeflora

et al. 2017

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Detailed literature inspections regarding the diterpenoids icetexone (1) and conacytone (3) reveal that the absolute configuration (AC) of these natural occurring compounds is not rigorously proven, despite they were originally isolated in 1976. This task is now completed by single-crystal X-ray diffraction Flack and Hooft parameters determination after processing data collected with Cu Kα graphite monochromated radiation. The AC of both compounds is further determined by vibrational circular dichroism measurements performed on icetexone acetate (2) and conacytone triacetate (4) since the solubility of 1 and 3 is limited. Comparison of the substituent chemical shifts (SCS) induced by acetylation of 1 and 3 to afford 2 and 4, respectively, reveals that in the case of icetexone, all six SCS values of the quinone ring are in excellent agreement with the expected values, while in the case of conacytone, three agree and three do not agree due to the presence of additional acetates near the quinone ring. Density functional theory calculations performed on 3-hydroxythymoquinone (6) and its tautomer 4-hydroxy-1,2-quinone 7, on 6-hydroxythymoquinone (8) and its tautomer ortho-quinone 9, and on icetexone (1) and the claimed natural occurring ortho-quinone tautomer romulogarzone (5) indicate that 2-hydroxy-1,4-quinones are more stable, by some 11-14 kcal/mol, than their 4-hydroxy-1,2-quinone tautomers, and therefore, romulogarzone (5) is inexistent.

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Section: Methodsmentioning

confidence: 99%

“…In turn, conacytone ( 3 ) was also isolated from S pubescens , S anastomosans , S candicans , and from another collection of S ballotaeflora …”

Section: Introductionmentioning

confidence: 99%

Absolute configuration of the diterpenoids icetexone and conacytone from Salvia ballotaeflora

et al. 2017

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“…This geographical distribution and the presence of cryptotanshinone in these plants had been considered chemical evidence of a probable evolutionary link between Asian, Californian, and Mexican Salvia spp. [34]. The presence of 20-norinuroyleanol (1) in the roots of S. semiatrata, and arucadiol (9) in the roots of S. anastomosans reinforce this link.…”

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confidence: 85%

“…Previous work on the roots of Mexican paleoendemic species Salvia axillaris led to the isolation of cryptotanshinone [34], a C-20-norabietanic diterpenoid originally Figure. X-Ray crystal structure of 20-norinuroyleanol (1) isolated from the roots of S. miltiorrhiza [4] and also found in several species belonging to subgenus Audibertia from Baja California (Mexico), such as S. mellifera, S. apiana, and S. munzii [25] [33]. This geographical distribution and the presence of cryptotanshinone in these plants had been considered chemical evidence of a probable evolutionary link between Asian, Californian, and Mexican Salvia spp.…”

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Abietane Diterpenoids from the Roots of some MexicanSalvia Species (Labiatae): Chemical Diversity, Phytogeographical Significance, and Cytotoxic Activity

Esquivel

Sánchez

Vergara

et al. 2005

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From the roots of some Mexican Salvia species, classified in subgenus Jungia, several diterpenoids belonging to abietane (i.e., 3-7), salvifolane (9-->20,10-->6)-diabeoabietane) (i.e., 2), and totarane (i.e., 10) carbocyclic skeletons were isolated together with two 20-nor- and one 6,7-secoabietane derivatives, 1 and 9, and 8, respectively. While compounds 2-10 were previously known from different sources, compound 1 is a new 20-norabietane derivative, whose structure was deduced by spectroscopic means and confirmed by X-ray-diffraction analysis. The phytogeographical significance of the distribution of 20-norabietanic diterpenoids in the genus suggested an evolutionary link between the Chinese and New-World Salvias. Compounds 2 and 8 were tested for cell-growth inhibition activity against several human cancer cell lines and human normal lymphocytes, while 2 showed a moderate cytotoxic activity, 8 exhibited a moderate yet selective activity against leukemia cell line.

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“…3 Other members of the icetexone subclass, such as 7,20-dihydroanastomosine ( 4 ), 19-deoxyisoicetexone ( 5 ), and 19-deoxyicetexone ( 6 ) have subsequently been isolated from the same source. 4 …”

Section: Introductionmentioning

confidence: 99%

Synthetic studies on the icetexones: enantioselective formal syntheses of icetexone and epi-icetexone

et al. 2013

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Two strategies for the synthesis of the icetexane diterpenoids icetexone and epi-icetexone that rely on Ga(III)-catalyzed cycloisomerization of alkynyl indene substrates to yield fused [6-7-6] tricycles have been explored. In the first approach, access to a tricycle bearing a gem-dimethyl group paved the way for explorations of C–H functionalization of one of the methyl groups in close proximity to a hydroxyl-directing group. This approach was ultimately unsuccessful and led only to ring cleaved products. In the second approach, an alkynyl indene substrate bearing a cyano substituent was utilized, which was effective in providing a functional handle to access the icetexone subclass of diterpenoids. A key epoxide opening/diazene rearrangement sequence was utilized to complete a formal synthesis of icetexone and epi-icetexone, which is discussed in detail. Furthermore, the cyano-containing substrate has been prepared in enantioenriched form using a Rh-catalyzed conjugate addition reaction, which now provides a route to the enantioselective synthesis of these natural products.

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Abietane and icetexane diterpenoids from Salvia ballotaeflora and Salvia axillaris

Cited by 24 publications

References 17 publications

Absolute configuration of the diterpenoids icetexone and conacytone from Salvia ballotaeflora

Absolute configuration of the diterpenoids icetexone and conacytone from Salvia ballotaeflora

Abietane Diterpenoids from the Roots of some MexicanSalvia Species (Labiatae): Chemical Diversity, Phytogeographical Significance, and Cytotoxic Activity

Synthetic studies on the icetexones: enantioselective formal syntheses of icetexone and epi-icetexone

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