Showing papers on "Benzopyrans published in 2010"
TL;DR: An expeditious construction of a benzopyran skeleton via Lewis acid-catalyzed C-H functionalization was achieved, affording the desired compounds in excellent chemical yields with short reaction times.
119 citations
TL;DR: SFE presented higher selectivity than the n-hexane maceration, and the best condition to extract the target metabolites has been determined to be at 50 degrees C and for the high molecular-weight compound, uliginosin B, higher pressures were required.
27 citations
TL;DR: In this article, halogen-free acyclic task-specific ionic liquids (TSILs) were synthesized as novel and recyclable catalysts for the synthesis of 5-oxo-5,6,7,8-tetrahydro-4H-benzo[b]pyrans by one-pot three-component condensation of aromatic aldehyde, malononitrile (or ethyl cyanoacetate), and dimedone (or 1,3-cyclohexanedione) in water.
Abstract: Some halogen-free acyclic task-specific ionic liquids (TSILs) were synthesized as novel and recyclable catalysts for the synthesis of 5-oxo-5,6,7,8-tetrahydro-4H-benzo[b]pyrans by one-pot three-component condensation of aromatic aldehyde, malononitrile (or ethyl cyanoacetate), and dimedone (or 1,3-cyclohexanedione) in water. The condensation accomplished successfully with good yields ranged from 86 to 94%. After the reaction, the products could simply be separated from the catalyst/water, and the catalyst could be reused at least 10 times without noticeably decreasing the catalytic activity. J. Heterocyclic Chem., 2010.
7 citations
TL;DR: The monophenol 19 and diphenol 25 were found to be good receptor ligands, devoid of estrogen agonist activity and associated with marked antiestrogenic activity of comparable order.
Abstract: Phenolic analogues of 2-[4-(2-piperidinoethoxy)phenyl]-3-phenyl-2H-1-benzopyran (1), a novel antiestrogen, were synthesized and evaluated for their structure-activity relationship. Incorporation of OH at position 7 was found to improve receptor affinity of the benzopyran while having no effect on its action as an antagonist. Similar substitution of 2-phenyl as well potentiated receptor affinity as well as antagonist activity of the prototype. The monophenol 19 and the diphenol 25 were thus found to be good receptor ligands, devoid of estrogen agonist activity and associated with marked antiestrogenic activity of comparable order. Both caused nearly complete inhibition of the estradiol stimulated uterine growth in rats as well as mice and were thus found to be better antiestrogens than tamoxifen, trioxifen, and LY-117018. A binding-site model for estrogen receptor rationalizing the structure-activity relationship of benzopyrans in relation to that of the triarylethylene and the triarylpropenone antiestrogens has been discussed.
6 citations
TL;DR: A series of substituted 2,3-diaryl-2H-1-benzopyrans have been synthesized and screened for their post-coital contraceptive activity in rats as discussed by the authors.
Abstract: Summary A series of substituted 2,3-diaryl-2H-1-benzopyrans have been synthesized and screened for their post-coital contraceptive activity in rats. Most of the compounds showed 100% inhibition in a single day schedule at a dose level of 1.0 mg/kg. Compound 32 was found to be the most active with a minimum effective dose (MED) of 0.2 mg/kg in single day testing. Further, it also showed high antiestrogenic activity and is devoid of any agonistic activity.
5 citations
TL;DR: An efficient synthesis of 4-alkyl-4-methyl-3,4-dihydro-2H,5H-pyrano[3,2-c]chromene-2,5-dione or 4-aryl-3.4- dihydropyrano-2 H,5 H-p Pyrano via reaction 4-hydroxycoumarin with Meldrum's acid and ketones or aldehydes is described.
Abstract: An efficient synthesis of 4-alkyl-4-methyl-3,4-dihydro-2H,5H-pyrano[3,2-c]chromene-2,5-dione or 4-aryl-3,4-dihydro-2H,5H-pyrano[3,2-c]chromene-2,5-diones via reaction 4-hydroxycoumarin with Meldrum's acid and ketones or aldehydes is described.
5 citations
TL;DR: In this article, a review of reaction chemistry and new ring synthetic methods for pyranones is presented, which covers work published in the calendar year 2010 and includes new ring synthesis methods for trioxanes, tetraoxane, dioxanes, trithianes and oxathianes.
Abstract: The review covers work published in the calendar year 2010. Novel reaction chemistry and new ring synthetic methods for pyrans, [1]benzopyrans, dihydro[1]benzopyrans (chromenes, chromans), [2]benzopyrans, dihydro[2]benzopyrans (isochromenes, isochromans), pyranones, coumarins, chromones, xanthenes, xanthones, thiopyrans, dioxins. dioxanes, trioxanes, tetraoxanes, dithianes, trithianes, oxathianes are reviewed.
3 citations
TL;DR: In this article, 3-Iodo-4-chalcogen-2 H -benzopyran derivatives underwent a direct Sonogashira cross-coupling reaction with several terminal alkynes in the presence of a catalytic amount of Pd(PPh 3 ) 2 Cl 2 with CuI as a co-catalyst, using Et 3 N as base and solvent.
3 citations
TL;DR: Amberlite IRA-400 (OH-) is an effective and reusable catalyst for the synthesis of the title benzopyrans (IV) via one-pot, three component condensation of dimedone, aldehydes and malononitrile as mentioned in this paper.
Abstract: Amberlite IRA-400 (OH-) is an effective and reusable catalyst for the synthesis of the title benzopyrans (IV) (12 examples) via one-pot, three component condensation of dimedone, aldehydes and malononitrile.
3 citations
TL;DR: In this paper, a novel protocol for intramolecular ketyl-olefin radical cyclization with low-valent titanium reagent is outlined, which allows the formation of the benzopyran nucleus from ortho-ally-loxy propiophenones as the sole product in moderate yields via IRC.
3 citations
Journal Article•
TL;DR: A microwave promoted novel protocol for the synthesis of diverse kinds of substituted benzopyrans from the corresponding variety of substituted hydroxy acetophenones and keto compounds using Amberlite IRA 400 resin (basic resin) under solvent-free conditions, has been developed.
Abstract: A convenient, microwave promoted novel protocol for the synthesis of diverse kinds of substituted benzopyrans from the corresponding variety of substituted hydroxy acetophenones and keto compounds using Amberlite IRA 400 resin (basic resin) under solvent-free conditions, has been developed. This protocol is mild and more efficient than the other reported methods.
TL;DR: In this article, a carbanion-olefin intramolecular 6-endo-trig cyclization reaction was used to provide 2-aroyl-3,4-dihydro-2H-benzopyrans.
Abstract: Utilization of a novel carbanion-olefin intramolecular 6-endo-trig cyclization reaction to provide 2-aroyl-3,4-dihydro-2H-benzopyrans is described. Through a sequence of a Wittig reaction, O-alkylation, and carbanion-olefin intramolecular cyclization, salicylaldehydes were converted into a series of new 2-aroyl-3,4-dihydro-2H-benzopyrans in two steps or in one-pot reaction.
TL;DR: In this paper, 3-Iodo-4-chalcogen-2 H -benzopyran derivatives underwent a direct Sonogashira cross-coupling reaction with several terminal alkynes in the presence of a catalytic amount of Pd(PPh 3 ) 2 Cl 2 with CuI as a co-catalyst, using Et 3 N as base and solvent.
Abstract: 3-Iodo-4-chalcogen-2 H -benzopyran derivatives underwent a direct Sonogashira cross-coupling reaction with several terminal alkynes in the presence of a catalytic amount of Pd(PPh 3 ) 2 Cl 2 with CuI as a co-catalyst, using Et 3 N as base and solvent. This cross-coupling reaction proceeded cleanly under mild conditions and was performed with propargylic alcohols, propargylic ethers, as well as alkyl and aryl alkynes, furnishing the correspondent 3-alkynyl-4-chalcogen-2 H -benzopyrans in good yields.
TL;DR: In this article, the intramolecular cycloaddition of o-quinomethanes generated in situ from o-hydroxybenzaldehydes and unsaturated alcohol in the presence of trimethyl orthoformate was investigated.
Abstract: Elemental iodine has been utilized as an efficient catalyst for the intramolecular[4 + 2]cycloaddition of o-quinomethanes generated in situ from o-hydroxybenzaldehydes and unsaturated alcohol in the presence of trimethyl orthoformate to afford the corresponding trans-annelated pyrano[3,2-c]benzopyrans in high yields with high diastereoselectivity
TL;DR: In this article, the Claisen rearrangement of aryl 1,1-dimethylpropargyl ethers under mild conditions was performed to obtain encecalin and desmethoxyencecalin.
Abstract: Mexican Bentonitic earth (Tonsil) catalyzed the Claisen rearrangement of aryl 1,1-dimethylpropargyl ethers under mild conditions to provide 2,2-dimethyl-2H-1-benzopyrans. The synthesis of encecalin 2f and desmethoxyencecalin 2i, two biologically active products among other natural products (2b, 2e) was performed by this procedure.
TL;DR: The phototransformations of 2-thienyl-3-cycloalkenyloxy benzopyrans in benzene lead to fused spirocyclic compounds bearing thiophene ring system as mentioned in this paper.
Abstract: The phototransformations of 2-thienyl-3-cycloalkenyloxy benzopyrans in benzene lead to fused spirocyclic compounds bearing thiophene ring system.
TL;DR: The leaves of Melicope ptelefolia provided 18 2,2-dimethyl-2H-1-benzopyrans, consisting of 14 new members, including one benzodipyran and four known compounds as discussed by the authors.
Abstract: Investigation of leaves of Melicope ptelefolia afforded 18 2,2-dimethyl-2H-1-benzopyrans, consisting of 14 new members, including one benzodipyran and four known compounds. Their structures were established by mass and NMR spectroscopy, especially NOE and HMBC experiments. © 1997 Elsevier Science Ltd. All rights reserved
TL;DR: In this paper, an unusual cyclocondensation of o-hydroxybenzaldehydes with 2,2-dimethoxypropane at ambient temperature was shown to produce 2,4-dimethyl-2-methyl-2H-1-benzopyrans in high yields with high diastereoselectivity.
Abstract: Iron(III) catalyses efficiently an unusual cyclocondensation of o-hydroxybenzaldehydes with 2,2-dimethoxypropane at ambient temperature to produce 2,4-dimethoxy-2-methyl-2H-1-benzopyrans in high yields with high diastereoselectivity. Also, it catalyses the formation of benzopyran derivatives from o-hydroxybenzaldehydes, acetone and trimethyl orthoformate. *IICT Communication No. 4675.
TL;DR: In this paper, substitution to the alkoxy group enhances the reactivity of the substrates and leads to the higher yields of the corresponding products, and the substitutions can be found in the literature.
Abstract: ortho-Substitution to the alkoxy group enhances the reactivity of the substrates and leads to the higher yields of the corresponding products [cf.
TL;DR: In this article, a series of 2-amino-substituted 5,6-benzo-2H-pyrans and their dimers were obtained by the reaction of 2hydroxy-benzaldehydes with enamines derived of (cyclo)aliphatic ketones.
Abstract: A series of 2-amino-substituted 5,6-benzo-2H-pyrans 14, 2-alkylidene-5,6-benzo-2H-pyrans 15, and their dimers 17 are obtained, depending on the condition used, by the reaction of 2-hydroxy-benzaldehydes 1 with enamines 9 derived of (cyclo)aliphatic ketones. Compounds 14, 15, and 17 can be transformed into 2-alkyl-benzopyrylium salts 16 or 2-[1-(2-hydroxyphenyl)-alken-2-yl]-benzopyrylium salts 23 by treatment with mineral acids. With aromatic aldehydes or the Vilsmeier reagent the compounds 14, 15, or 17 are transformed into deeply colored 2-(aryl-alkenyl)-benzopyrylium perchlorates 25 or 2-(2-dialkylamino)-alkenyl-benzopyrylium salts 26, respectively.