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Garazd, M. M.; Garazd, Ya. L.; Shilin, S. V.; Panteleimonova, T. N.; Khilya, V. P.

doi:10.1023/a:1020423826071

Cited by 10 publications

(7 citation statements)

References 9 publications

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“…Elemental analyses of all compounds agreed with those calculated. Hydroxycoumarins 1-8 were synthesized as before [5,6]; 12 and 20, by the literature method [11]. Pharmacopoeic cytisine isolated from Thermopsis alterniflora was used.…”

Section: Methodsmentioning

confidence: 99%

Modified coumarins. 22. Synthesis of N-coumarinyloxyacetyl derivatives of cytisine

et al. 2006

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N-Acetyl derivatives of cytisine modified by coumarins were synthesized.Adding a natural alkaloidal fragment to organic molecules leads in most instances to the appearance of new biological properties. Cytisine possesses potent pharmacological activity [1,2]. On the other hand, coumarins form a group of structurally varied natural bioregulators of plant origin that are based on the benzopyran-2-one skeleton [3]. Depending on the structure, natural coumarins and their synthetic analogs possess a wide spectrum of biological activity [4]. We synthesized a series of cytisine derivatives that contain the coumarin moiety, a heterocycle that is widely distributed in nature.Hydroxycoumarins 1-8 that were required for further transformations were prepared by Pechmann condensation of polyphenols (resorcinol, 2-methylresorcinol, orcine) and ethyl-2-oxocyclopentanecarboxylate or ethyl-2-oxocyclohexanecarboxylate in the presence of conc. H 2 SO 4 [5, 6].Alkylation of 1-8 in acetone in the presence of potash by ethylchloroacetate produced ethyl esters 9-16, saponification of which by NaOH in aqueous propan-2-ol with subsequent acidolysis gave the corresponding acids 17-24.Cytisine was modified by two methods. The first method of cytisine N-acylation was based on the method of activated esters that is widely applied in peptide synthesis [7]. We used the highly reactive N-hydroxysuccinimide ester to activate the carboxylic function [8]. Activated esters were prepared by reacting corresponding acids 17-24 and N-hydroxysuccinimide (SuOH) in absolute dioxane using diisopropylcarbodiimide (DIC) as the condensing agent. Condensation of the resulting esters with cytisine in dioxane at room temperature formed in high yields the N-acyl cytisine derivatives 25-32, which contain coumarin moieties.The second method was based on activation of the carboxylic function of coumarinyloxyacetic acids using N,N-carbonyldiimidazole (CDI) [9,10]. Reaction of acids 17-24 and CDI in absolute DMF formed N-acylimidazoles, which were converted in high yields and smoothly by cytisine to the corresponding N-acyl cytisine derivatives 25-32.Analysis of PMR spectra revealed that a doubled set of signals was found for all prepared compounds. Obviously formation of amide bonds in such systems produces invertomers with hindered rotation around the N-C bond that can be considered to be Z-and E-isomers. The presence of amide conjugation was confirmed by temperature experiments. Thus, heating samples of the prepared compounds to 100°C caused signals in the PMR spectrum to coalesce because of free rotation of the substituents around the N-C bond.

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Section: Methodsmentioning

confidence: 99%

Modified coumarins. 22. Synthesis of N-coumarinyloxyacetyl derivatives of cytisine

et al. 2006

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“…As the objects of investigation, we chose substituted furocoumarins [27]: 4′,5′-dimethyl-3,4-cyclohexyl psoralene (FC1) and 4′-methyl-3,4-cycloheptyl psoralene (FC2):…”

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Luminescent analysis of photoinduced detoxification of substituted furocoumarins

et al. 2008

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We have studied the effect of two detoxifying factors (UV radiation from different sources and humic substances) on the toxicity of alcoholic solutions of substituted coumarins. The change in the characteristics of the substituted coumarins was monitored spectrophotometrically. The toxicity of solutions of the substituted coumarins was monitored using a bioluminescence test system. We have shown that efficient detoxification of an alcoholic solution of coumarins occurs as a result of addition of humic substances. We have observed a dependence of the detoxification both on the structure of the studied compounds and on the characteristics of the source.

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“…Natural furocoumarins and their synthetic analogs have various physiological activities that depend on the chemical structure. Thus, furocoumrains with carbocycles annellated at the 5,6-positions exhibit photoantiproliferative [2-5] and cardiotropic [6] activities and act as CNS stimulants [6].In continuation of research on the synthesis and properties of furocoumarins [6-9], herein we report the preparation of tetracyclic psoralen-type furocoumarins containing a cycloheptane ring annellated to the 5,6-positions of a furo[3,2-g]chromen-7-one.3-Hydroxy-8,9,10,11-tetrahydrocyclohepta[c]chromen-6-one (1) and its 4-methyl analog (2) that were necessary for further transformations were prepared by Pechmann condensation of resorcinol and 2-methylresorcinol, respectively, with methyl-2-oxo-1-cycloheptanecarboxylate in the presence of conc. H 2 SO 4 at 0°C [10, 11].…”

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Modified coumarins. 24. Synthesis of cycloheptane-annellated tetracyclic furocoumarins

Garazd

Ogorodniichuk

et al. 2006

Chem Nat Compd

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Furocoumarins comprise natural compounds with a variety of structures that in most instances are derivatives of the linear furocoumarin psoralen [1]. Natural furocoumarins and their synthetic analogs have various physiological activities that depend on the chemical structure. Thus, furocoumrains with carbocycles annellated at the 5,6-positions exhibit photoantiproliferative [2-5] and cardiotropic [6] activities and act as CNS stimulants [6].In continuation of research on the synthesis and properties of furocoumarins [6-9], herein we report the preparation of tetracyclic psoralen-type furocoumarins containing a cycloheptane ring annellated to the 5,6-positions of a furo[3,2-g]chromen-7-one.3-Hydroxy-8,9,10,11-tetrahydrocyclohepta[c]chromen-6-one (1) and its 4-methyl analog (2) that were necessary for further transformations were prepared by Pechmann condensation of resorcinol and 2-methylresorcinol, respectively, with methyl-2-oxo-1-cycloheptanecarboxylate in the presence of conc. H 2 SO 4 at 0°C [10, 11]. 1, 23, 45: R = H; 2, 24, 46: R = Me; 3, 25: R = H, R 1 = Me; 4, 26: R = R 1 = Me, 5, 27: R = H, R 1 = t-Bu; 6, 28: R = Me, R = t-Bu; 7, 29: R = H, R 1 = R 2 = Me; 8, 30: R = R 1 = R 2 = Me, 9, 31: R = H, R 1 = Me, R 2 = Ph; 10, 32: R = R 1 = Me, R 2 = Ph; 11, 33: R = H, R 1 = Ph; 12, 34: R = Me, R 1 = Ph, 13, 35: R = H, R 1 = 4-FPh; 14, 36: R = H, R 1 = 4-FPh; 15, 37: R = H, R 1 = 4-ClPh; 16, 38: R = Me, R 1 = 4-ClPh 17, 39: R = H, R 1 = 4-BrPh; 18, 40: R = Me, R 1 = 4-BrPh; 19, 41: R = H, R 1 = 4-MeOPh; 20, 42: R = Me, R 1 = 4-MeOPh 21, 43: R = H, R 1 = 3-MeOPh; 22, 44: R = Me, R 1 = 3-MeOPh

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Untitled

Cited by 10 publications

References 9 publications

Modified coumarins. 22. Synthesis of N-coumarinyloxyacetyl derivatives of cytisine

Modified coumarins. 22. Synthesis of N-coumarinyloxyacetyl derivatives of cytisine

Luminescent analysis of photoinduced detoxification of substituted furocoumarins

Modified coumarins. 24. Synthesis of cycloheptane-annellated tetracyclic furocoumarins

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