New ester and furocoumarins from the roots of Pituranthos tortuosus

Abdel‐Kader, Maged S.

doi:10.1590/s0103-50532003000100008

Cited by 20 publications

(11 citation statements)

References 12 publications

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“…of diacid chloride 1 in CH 2 Cl 2 and in the presence of pyridine and DMAP afforded the cyclophane 4a in 56% yield. [19][20][21][22][23][24] Using the new dual catalyst system not only increased the yield of the product, but also improved the reaction rate. The 1 H NMR spectrum of cyclophane 4a displayed the aromatic methyl protons as a singlet at d 2.27, OCH 2 CH 2 protons as two triplet at d 3.80 and 4.55 with J 4.0 Hz, in addition to aromatic protons.…”

Section: Resultsmentioning

confidence: 99%

Synthesis, crystal structure and biological activity of novel diester cyclophanes

Zhang¹,

Yang²,

Fang³

et al. 2012

J. Braz. Chem. Soc.

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Uma série de novos ciclofanos diésteres foi sintetizada por esterificação de cloreto de 1,2 benzenodicarbonilo com oito diferentes dióis sob condições de elevada diluição. As estruturas dos compostos foram verificadas por análise elementar, ressonância magnética nuclear (NMR) de 1 H, espectroscopia IR e espectrometria de massas de alta resolução (HRMS). As estruturas cristalinas de dois dos compostos foram caracterizadas por difratometria de raios X (XRD) de monocristais. Todos os novos ciclofanos foram avaliados com relação a suas atividades biológicas e os resultados mostraram que alguns destes compostos têm baixas atividades antibacterianas e antifúngicas.A series of novel diester cyclophanes was synthesized by esterification of 1,2-benzenedicarbonyl chloride with eight different diols under high dilution conditions. The structures of the compounds were verified by elemental analysis, 1 H nuclear magnetic resonance (NMR), IR spectroscopy and high resolution mass spectrometry (HRMS). The crystal structures of two compounds were characterized by single crystal X-ray diffractometry (XRD). All the new cyclophanes were evaluated for biological activities and the results showed that some of these compounds have low antibacterial or antifungal activities.

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Section: Resultsmentioning

confidence: 99%

Synthesis, crystal structure and biological activity of novel diester cyclophanes

Zhang¹,

Yang²,

Fang³

et al. 2012

J. Braz. Chem. Soc.

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“…169°C [24], 172-174°C [25]), empirical formula C 11 H 12 O 3 . IR spectrum (KBr, cm -1 ): 3124, 2968, 1644, 1582, 1572, 1484, 1372, 1330, 1312 2,2-Dimethylchroman-7-ol (13). A solution of 12 (1.92 g, 10 mmol) in CH 3 OH (20 mL) was vigorously stirred, treated with zinc dust (6.4 g, 100 mmol), dropwise with conc.…”

Section: -Hydroxy-22-dimethylchroman-4-one (12)mentioning

confidence: 99%

“…Examples of metabolites based on 8,8-dimethyl-7,8-dihydropyrano[3,2-g]chromen-2,6-dione are graveolone (6) produced by Anethum graveolens [9][10][11][12] and Pituranthos tortuosus [13] or clausenine (5-hydroxygraveolone) (7) isolated from Clausena heptaphylla and C. excavata [14][15][16].…”

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confidence: 99%

“…Kabbe condensation [20] of 2,4-dihydroxyacetophenone and acetone in the presence of pyrrolidine gave 7-hydroxy-2,2,-dimethylchroman-4-one (12). Clemensen reduction of 12 by zinc dust in HCl gave 2,2-dimethylchroman-7-ol (13 (14), a modified analog of dihydroxantiletin containing an annelated cyclopentane fragment. 5,7-Dihydroxy-2,2-dimethyl-4-chromanone (15) was synthesized by Friedel-Krafts acylation of floroglucinol with 3,3-dimethylacrylic acid in the presence of BF 3 etherate [21].…”

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confidence: 99%

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Modified coumarins. 13. Synthesis of cyclopentane-annelated pyranocoumarins

Garazd

Khilya

2004

Chem Nat Compd

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Modified pyranocoumarins containing a condensed cyclopentane fragment were synthesized by adjoining a 2,2-dimethyltetrahydropyran ring to a 2,3-dihydrocyclopenta [c]chromen-4-one system and annelation of a pyrone ring to a 2,2-dimethylchromane.Pyranocoumarins (chromeno-α-pyrones) are widely distributed in nature and contain a 2,2-dimethylpyran ring annelated to a benzopyran-2-one system at the 6,7; 5,6; or 7,8 positions [1]. Most natural pyranocoumarins are derivatives of the linear pyranone xantiletin (1) or its angular isomer seselin (2).Pyranocoumarins also include coumarins with a condensed 2,2-dimethyldihydropyran ring or an annelated 2,2-dimethyltetrahydropryan-4-one moiety. Typical representatives of natural 8,8-dimethyl-7,8-dihydropyrano[3,2-g]chromen-2-ones are dihydroxantiletin (3) isolated from Seseli tortuosum [2], Ammi majus [3], and Cassia pumila [4]; kanzonol Q (4) produced by Glycyrrhiza uralensis [5]; and isoglycycoumarin (5) isolated from Glycyrrhiza aspera [6,7], G. inflata, G. glabra, and G. uralensis [8].Examples of metabolites based on 8,8-dimethyl-7,8-dihydropyrano[3,2-g]chromen-2,6-dione are graveolone (6) produced by Anethum graveolens [9][10][11][12] and Pituranthos tortuosus [13] or clausenine (5-hydroxygraveolone) (7) isolated from Clausena heptaphylla and C. excavata [14][15][16].Our goal was to modify the structure of 2,3-dihydrocyclopenta[c]chromen-4-one by adjoining a 2,2-dimethylpyran ring. The cyclopentane-annelated dihydropyranocoumarins were synthesized by two methods: 1) addition of a 2,2-dimethyltetrahydropyran ring to the coumarin and 2) annelation of a pyrone ring to the 2,2-dimethylchromane core.Because they were necessary for further transformations, 7-hydroxy-6-methyl-2,3-dihydrocyclopenta[c]chromen-4-one (8) and 9-hydroxy-7-methyl-2,3-dihydrocyclopenta[c]chromen-4-one (9) were prepared by Pechmann condensation of 2-methylresorcinol and orcinol, respectively, with ethyl-2-oxocyclopentanecarboxylate in the presence of conc. H 2 SO 4 [17]. Condensation of 8 and 3,3-dimethylallylbromide in the presence of p-toluenesulfonic acid [18] gave the linear dihydropyranocoumarin 6,8,8-trimethyl-2,3,9,10-tetrahydrocyclopenta[c]pyrano[3,2-g]chromen-4-one (10). Using 9 in this condensation forms the angular isomer 2,2,5-trimethyl-3,4,10,11-tetrahydrocylopenta[c]pyrano[2,3-f]chromen-8-one (11). The results were analogous if 3-methyl-2-buten-1-ol instead of 3,3-dimethylallylbromide was used as the alkylating agent. PMR spectra of 10 and 11 show simplified splitting patterns for the aromatic protons compared with the starting coumarins owing to a lack of coupling for the benzopyran H-6 proton. For 10, H-11 is observed as a singlet at 6.99 ppm; for 11, H-6 at 6.73 ppm.

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“…Fumigations of the aerial parts of the plant are used in the treatment of sheep scabies. Phytochemical investigations on P. triradiatus and tortuosus have shown the presence of coumarins [4,7,8] and of flavonoids [9]. P. scoparius contains an essential oil in the stem and in the seed [10], previously known to possess antispasmodic activity [11].…”

Section: Introductionmentioning

confidence: 99%