Showing papers on "Benzopyrans published in 2006"
TL;DR: The first organocatalyzed asymmetric synthesis of chiral benzopyrans was reported in this article, where a domino reaction involving an oxa-Michael attack of salicylic aldehyde derivatives onto α,β-unsaturated aldehydes was performed.
Abstract: Benzopyrans, or chromenes, are widespread in nature and are considered to be a privileged scaffold in medicinal chemistry. Herein, we report the first organocatalyzed asymmetric synthesis of chiral benzopyrans. The benzopyran unit is constructed through a domino reaction involving an oxa-Michael attack of salicylic aldehyde derivatives onto α,β-unsaturated aldehydes, activated through iminium-ion formation with the organocatalyst, followed by an intramolecular aldol reaction and subsequent elimination of water. This overall reaction sequence provides benzopyrans with aromatic C-2 substituents in up to 60% yield and 60% enantioselectivity, while C-2 aliphatic analogues can be obtained in 90% enantiomeric excess, but with only 20% yield. The role of additives, as well as the possible racemization of the benzopyran, was also investigated.
112 citations
TL;DR: Radioisotopic and electrophysiological investigations performed with R/S-6-chloro-4-(3-chlorophenylaminocarbonylamino)-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran confirmed that the drug activated pancreatic KATP channels.
Abstract: In the search of a novel series of benzopyrans structurally related to (+/-)-cromakalim and acting as pancreatic beta-cell potassium channel openers, several R/S-3,4-dihydro-2,2-dimethyl-6-halo-4-(phenylaminocarbonylamino)-2H-1-benzopyrans with or without a substituent on the phenyl ring in the 4-position were synthesized. Their activity on rat-insulin-secreting cells and rat aorta rings was compared to that of the K(ATP) channel activators (+/-)-cromakalim, diazoxide, (+/-)-pinacidil, and compound 4. Structure-activity relationships indicated that the most pronounced inhibitory activity on the pancreatic tissue was obtained by introducing a meta- or para-electron-withdrawing group (a chlorine atom) on the C-4 phenyl ring (drugs 37-42). Such molecules, unlike the parent compound (+/-)-cromakalim, also exhibited a high selectivity for the pancreatic tissue versus the vascular tissue. Radioisotopic and electrophysiological investigations performed with R/S-6-chloro-4-(3-chlorophenylaminocarbonylamino)-3,4-dihydro-2,2-dimethyl-2H-1-benzopyran (38) confirmed that the drug activated pancreatic KATP channels.
35 citations
TL;DR: Oxapalladacycles were immobilized on polystyrene-divinylbenzene supports and treated with 3-aryl-2-propynoates or 1-alkyl-1,2-propadienes to afford 2H-1-benzopyrans in yields superior to those for solution-phase experiments.
Abstract: Oxapalladacycles were immobilized on polystyrene−divinylbenzene supports and treated with 3-aryl-2-propynoates or 1-alkyl-1,2-propadienes to afford 2H-1-benzopyrans in yields superior to those for solution-phase experiments. Isolation of benzopyrans was facilitated, and 71−80% of the palladium was recovered. Effects of resin loading with phosphorus and palladium were studied, and the optimum immobilized palladacycles featuring a medium loading with P (1.35 mmol P/g) and a high loading with Pd (Pd:P ratio 1:1.7) were identified. Resins with higher swelling capacities were more reactive.
34 citations
TL;DR: In this article, the properties of three oxobenzo[ f ]benzopyrans as new fluorogenic photolabile protecting groups for the carboxylic function of amino acids were studied.
33 citations
TL;DR: Aromatic carbonyl compounds undergo smooth intramolecular radical cyclization with alkenes or alkynes using titanocene(III) chloride to furnish the corresponding benzopyrans as discussed by the authors.
21 citations
TL;DR: In this paper, the interaction of 2-iminocoumarin-3 carboxamides with a series of 2aminothiophene-3-carboxamide was studied.
Abstract: In the course of our research on the synthesis of coumarins, the interaction of 2-iminocoumarin-3-carboxamides with a series of 2-aminothiophene-3-carboxamides was studied. It was established that the initial products - 2-substituted coumarin-3-carboxamides - can undergo rearrangement to 2-(coumarin-3-yl)thieno[2,3-d]pyrimidin-4-ones by refluxing in DMF.
9 citations
TL;DR: In this paper, a series of benzopyrans as potassium channel activators have been carried out using a large set of distance-based topological indices, including negentropy and molecular redundancy indices.
6 citations
TL;DR: In this article, an efficient and general synthesis of benzopyrans was achieved by ethylenediamine diacetate-catalyzed reactions of resorcinols with α,β-unsaturated aldehydes in moderated yields.
Abstract: An efficient and general synthesis of benzopyrans is achieved by ethylenediamine diacetate-catalyzed reactions of resorcinols with α,β-unsaturated aldehydes in moderated yields. As an application of this methodology, biologically interesting confluentin, which was known to have an inhibitory effect on histamine release is synthesized in one step. Also, natural daurichromenic acid, which has highly potent anti-HIV activity, is successfully synthesized in one step.
4 citations
TL;DR: The reaction of homophthaldehyde with 8-(benzylamino)menthol is regio-and diastereo-selective, leading to the chiral perhydro-1,3-benzoxazine 3 as a single diastereoisomer.
3 citations
TL;DR: In this article, the synthesis of photochromic 3,3-di(4 ′ -fluorophenyl)-3H-benzopyrans fused to an indole moiety is described.
Abstract: The synthesis of photochromic 3,3-di( 4 ′ -fluorophenyl)-3H-benzopyrans fused to an indole moiety
is described. The structures of photomerocyanines elucidated by NMR spectroscopy and spectrokinetic data ( λ max of colored form, colorability, and rate constant of bleaching) obtained by UV-visible spectroscopy are reported.
3 citations
TL;DR: In this paper, the synthesis of 1-(6-hydroxy-4-methoxy-7,7-dimethyl-6,7dihydro-5H-furo[3,2g]chromen-5-yl) pyrrolidin-2-one (7) analogue to Cromakalim was described.
Abstract: We describe the synthesis of 1-(6-hydroxy-4-methoxy-7,7-dimethyl-6,7-dihydro-5H-furo[3,2-g]chromen-5-yl) pyrrolidin-2-one (7) analogue to Cromakalim. Moreover, the synthesised furochromanone used to synthesise a fused heterocyclic compounds containing thiophene and coumarin rings via Gewald and Wittig reactions; respectively.
Patent•
19 Apr 2006
TL;DR: In this paper, a process for synthesizing 3-(5i»-substituent-2-benzoxazolyl)-7-diethylamino-2H- 1benzopyran-2
Abstract: A process for synthesizing 3-(5i»-substituent-2-benzoxazolyl)-7-diethylamino-2H- 1-benzopyran-2-one includes such steps as the reflux reaction between ethyl cyanoacetate, 4-N,N-diethylamino salicylaldehyde and 0-aminophenol derivative in non-protonic polar solvent for 10-24 hr under the action of catalyst, and post-treating.
TL;DR: Aromatic carbonyl compounds undergo smooth intramolecular radical cyclization with alkenes or alkynes using titanocene(III) chloride to furnish the corresponding benzopyrans.
Abstract: Aromatic carbonyl compounds undergo smooth intramolecular radical cyclization with alkenes or alkynes using titanocene(III) chloride to furnish the corresponding benzopyrans. The radical initiator, Cp2TiCl, was prepared in situ from commercially available titanocene dichloride (Cp2TiCl2) and zinc dust in THF under argon.
TL;DR: An alkylation/cyclization sequence, with both steps mediated by the ortho-N-methylformamido-phenylsulfinyl function, provided two new C-C bonds and an efficient entry to 1-aryl-tetralins and 4-arylbenzopyrans as discussed by the authors.
Abstract: An alkylation/cyclization sequence, with both steps mediated by the ortho-N-methylformamido-phenylsulfinyl function, provided two new C–C bonds and an efficient entry to 1-aryl-tetralins and 4-aryl-benzopyrans. Scope and limits of the process have been studied in detail.
TL;DR: The first organocatalyzed asymmetric synthesis of chiral benzopyrans was reported in this paper, where a domino reaction involving an oxa-Michael attack of salicylic aldehyde derivatives onto α,β-unsaturated aldehydes was performed.
Abstract: Benzopyrans, or chromenes, are widespread in nature and are considered to be a privileged scaffold in medicinal chemistry. Herein, we report the first organocatalyzed asymmetric synthesis of chiral benzopyrans. The benzopyran unit is constructed through a domino reaction involving an oxa-Michael attack of salicylic aldehyde derivatives onto α,β-unsaturated aldehydes, activated through iminium-ion formation with the organocatalyst, followed by an intramolecular aldol reaction and subsequent elimination of water. This overall reaction sequence provides benzopyrans with aromatic C-2 substituents in up to 60% yield and 60% enantioselectivity, while C-2 aliphatic analogues can be obtained in 90% enantiomeric excess, but with only 20% yield. The role of additives, as well as the possible racemization of the benzopyran, was also investigated.
TL;DR: In this article, the interaction of 2-iminocoumarin-3 carboxamides with a series of 2aminothiophene-3-carboxamide was studied.
Abstract: In the course of our research on the synthesis of coumarins, the interaction of 2-iminocoumarin-3-carboxamides with a series of 2-aminothiophene-3-carboxamides was studied. It was established that the initial products - 2-substituted coumarin-3-carboxamides - can undergo rearrangement to 2-(coumarin-3-yl)thieno[2,3-d]pyrimidin-4-ones by refluxing in DMF.
TL;DR: In this paper, the synthesis of biologically interesting ( −)-cannabichromene, (−)-daurichromenic acid, and −-cannabeachromene is described.
Abstract: Total synthesis of biologically interesting (′)-cannabichromene, (′)-cannabichromenic acid, and (′)-daurichromenic acid is described. The key step in the synthetic strategy involves the formation of benzopyrans by ethylenediamine diacetate-catalyzed reactions of resorcinols with α,β-unsaturated aldehydes.
TL;DR: In this article, the DBU-catalyzed reactions of salicylic aldehydes with 3-methylpenta-3,4-dien-2-one, 3-benzylmethylbuta-2,3dienoate gave the corresponding functionalized 2H-1-chromenes in good to excellent yields and good diastereoselectivities in some cases in DMSO.
Abstract: DBU-catalyzed reactions of salicylic aldehydes with 3-methylpenta-3,4-dien-2-one, 3-benzylpenta-3,4-dien-2-one, or ethyl 2-methylbuta-2,3-dienoate gave the corresponding functionalized 2H-1-chromenes in good to excellent yields and good diastereoselectivities in some cases in DMSO, respectively.