Antibacterial activity of nitrobenzofurans

Powers, Larry J.; Mertes, Mathias P.

doi:10.1021/jm00300a020

Cited by 20 publications

(11 citation statements)

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(3 reference statements)

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“…IR spectra were recorded on Perkin-Elmer 257-FTIR 1600 series spectrometer, using the KBr disc method for solid materials. 1 H and 13 C NMR spectra were recorded at 300 and 75 MHz using a Varian VXR 300 machine at 25°C (chemical shifts in d ppm). Mass spectra were recorded on Shimadzu QP 2010 GC MS instrument.…”

Section: Methodsmentioning

confidence: 99%

“…The anhydride 1 was synthesised from 3-carboxymethyl-6-methoxy benzofuran-2-carboxylic acid using the reported method. 8 7-Methoxy-2-(4-methoxyphenyl) [1]benzofuro [2,3-c] 10-Methoxy-6-(4-methoxyphenyl)-5H- [1]benzofuro [3',2':3,4] pyrido [3,2-b] [1,4] [1]benzofuro [3,2-d]thiazolo [4,5-b]pyridin-5(4H)-one (5): The bromo-compound 3 (4.0 g, 0.01 mol) in ethanol (75 ml) was stirred at 50°C, and triethylamine (1.0 g, 0.01 mol) and thiourea (0.76 g, 0.01 mol) were added. The reaction mixture was then heated to reflux for 5 h. Excess of ethanol was removed under vacuum and the reaction mass was poured onto 100 g crushed ice and stirred vigorously.…”

Section: -Methoxypyranomentioning

confidence: 99%

“…

2-Carboxy-6-methoxybenzofuran-3-acetic acid anhydride is utilised for the synthesis of novel polycyclic heteroaromatic compounds in which the benzofuran ring is fused or bound to pyrido [1,4]benzothiazine, thiazole, pyridine, pyrazolopyridine, pyrazole, pyrano-pyridine, and pyrazolo [1,5-a]pyrido[3,2-e]pyrimidines using versatile reaction strategies.

…”

mentioning

confidence: 99%

“…Benzofurans [1][2][3][4] and 2-pyridones [5][6][7] are well known for their broad spectrum of biological activities. This has generated much interest in the synthesis of heterocycles bearing the benzofuran and pyridone moieties.…”

mentioning

confidence: 99%

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Novel heterocyclic compounds from 2-carboxy-6-methoxybenzofuran-3-acetic acid anhydride

Patankar

Khombare

Khanwelkar

et al. 2008

Journal of Chemical Research

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Section: Methodsmentioning

confidence: 99%

Section: -Methoxypyranomentioning

confidence: 99%

“…

…”

mentioning

confidence: 99%

mentioning

confidence: 99%

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Novel heterocyclic compounds from 2-carboxy-6-methoxybenzofuran-3-acetic acid anhydride

Patankar

Khombare

Khanwelkar

et al. 2008

Journal of Chemical Research

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“…Bien qu'elle ne convienne pas mieux que d'autres pour assurer la nitration des benzofurannes 1 et 3 non substitues en position 2, elle est parfaitement utilisable dans le cas du methyl-2 benzofuranne 2. Si, en effet, le benzofuranne 1 ne donne ainsi que des traces de nitro-2 benzofuranne 4 (2), tandis que le methyl-3 benzofuranne 3 est cornpletement dCcomposC, le methyl-2 benzofuranne 2 fournit une petite quantitC du derive nitre en 3 9 qui avait deja ttC decrit (25), cBtt d'une majorite de son isomere 10 inconnu jusqu'i present.…”

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Application en série benzofurannique d'un nouveau procédé de nitration par l'acide nitrique en présence de chlorure stannique

Einhorn¹,

Demerseman²,

Royer³

1983

Can. J. Chem.

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JACQUES EINHORN, PIERRE DEMERSEMAN ct R E N~ ROYER. Can. J. Chem. 61. 2287Chem. 61. (1983. On determine la possibilitk d'Ctcndrc en sCric benzofurannique une nouvclle tcchnique de nitration par l'ac~de nitrique, en prCscncc de chlorure stanniquc, dans Ic chlorure de methylkne. Cettc technique mirite d'Ctre retenue pour la commoditk de sa niise cn oeuvrc ct la divcrsitb dcs produits qu'elle cst susccptiblc dc fournir, selon les conditions exper~mcntales.JACQUES EINHORN, PIERRE DEMERSEMAN, and RENE ROYER. Can. J. Chem. 61, 2287Chem. 61, (1983. A new nitration technique, using nitric acid in the prcscncc of stannic chloride in dichloromethane, has been extcnded to a series of bcnzofurans. Thc ease of performing the reaction as well as the diversity of products that can bc obtained under various cxpcrimcntal conditions make it a worthwhile technique.[Journal translation]Le benzofuranne et la plupart de ses derives dont I'hCterocycle n'est pas substitue sont trop fragiles pour que leur nitration puisse Ctre effectuee avec des rendements satisfaisants dans les conditions usuelles, au moyen, par exemple, d'acide nitrique dans I'acide ou I'anhydride acetique (1 -16). Or, nous avons recemment montre que la nitration des composes aromatiques peut Ctre assuree d e fagon commode et rentable au moyen d'un complexe -C1,Sn(N02)2 -que forment l'acide nitrique et le chlorure stannique dans le chlorure de methylene (17). I1 nous a semblC inttressant de preciser dans quelle mesure cette methode pouvait Ctre etendue en serie benzofurannique, etant donne notamment la diversite et I'importance des propriCtCs biologiques des nitro-2 benzofurannes (10, 13, 18 -24)..Nous I'avons donc appliquee au benzofuranne 1 lui-mCme, ainsi qu'au methyl-2 benzofuranne 2 et, pour comparaison, au methyl-3 benzofuranne 3.Des resultats exposes sur le tableau ci-joint, il ressort que la methode en question presente les n~& m e s avantages en serie benzofurannique qu'en serie benzenique. Bien qu'elle ne convienne pas mieux que d'autres pour assurer la nitration des benzofurannes 1 et 3 non substitues en position 2, elle est parfaitement utilisable dans le cas du methyl-2 benzofuranne 2. Si, en effet, le benzofuranne 1 ne donne ainsi que des traces de nitro-2 benzofuranne 4 (2), tandis que le methyl-3 benzofuranne 3 est cornpletement dCcomposC, le methyl-2 benzofuranne 2 fournit une petite quantitC du derive nitre en 3 9 qui avait deja ttC decrit (25), cBtt d'une majorite de son isomere 10 inconnu jusqu'i present.Par ailleurs, comme un bon nombre de nitro-2 benzofurannes ont ete obtenus jusqu'ici par deplacement "ipso" d'un groupement acttyle plut6t que par substitution directe en position 2 , nous avons utilise la m&me mtthode pour traiter I'acCtyl-2 benzofuranne 5 et I'acCtylI2 trimethyl-3,5,6 benzofuranne 6 '~r t i c l e LXVIII de la sCric: "Recherches sur le benzofuranne". LVII: voir ref. 16.( 12). Nous y avons enfin soumis, a titre complementaire, I'acide coumarilique 7 et I'acide methyl-3 coumarilique 8, afin de preciser dans quelle mesure des der...

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Thermal and Photochemical Rearrangement of 3‐Substituted 2‐Methylbenzofuran Epoxides and Their Valence‐Isomeric Quinone Methides

1994

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The dimethyldioxirane oxidation of the 3-substituted 2-methylbenzofurans 1 [la: 3(E)-styryl, lb: 3-acetoxy, lc: 3-(tert-butyldimethylsilyloxy)] is reported. Only quinone methide 3a, none of the benzofuran epoxides 2a-c, could be detected by 'H-and 13C-NMR spectroscopy at low temperature (-3O"C), which on photoisomerization led to chromene 7a. The benzofuran-3-ones 5b, c and the a-diketone 6c are presumably formed by thermal isomerization of the transient benzofuran epoxides 2b, c and quinone methide 3c.Benzofuran epoxides 2 and their valence-isomeric quinone methides 3, both readily accessible by dimethyldioxirane oxidation of benzofurans 1, have been shown to be very reactive compounds [']. Thus, the epoxides 2 and quinone methides 3 rearrange thermally above -20°C to the allylic alcohols 4 and their tautomeric phenols 4' (Scheme 1 ). Scheme 1 RDue to the fact that the allylic alcohols 4 and their ringopened tautomeric phenols 4' interconvertf'a,q, it has been difficult to establish rigorously, whether these derive from the epoxides 2 or their valence-isomeric quinone methides 3. However, the 1,s-sigmatropic shift in the rearrangement 3 -+ 4 (Scheme 1) requires isomerization of ( 9 -3 to (E)-3, which usually is promoted photochemically. It was our [*I Undergraduate research participant, March 1992. interest, therefore, to examine benzofuran epoxides 2 and their corresponding quinone methides 3 with substituents which cannot rearrange to the allylic alcohols 4 andlor their phenol tautomers 4' (Scheme 1) to provide mechanistic insight into their mode of formation. For this reason, the benzofurans la-c were selected as model compounds, and their dimethyldioxirane oxidation was examined. We report presently on the chemical fate of the transient benzofuran epoxides 2 and their valence-isomeric quinone methides 3. Results and DiscussionThe dimethyldioxirane[21 oxidation of a 92:s mixture of the 3-styrylbenzofurans (EJ-lal(Z)-l a gave exclusively the (E)-styryl-substituted quinone methide (Z)-3a (Scheme 2), which could be isolated at -20°C as a dark-red solid, while benzofuran ( 3 -1 a was not oxidized under these conditions, as revealed by NMR data. At temperatures above 0°C dimethyldioxirane oxidized both, the isomers (@-la and (3-1 a. However, at this elevated temperature decomposition or overoxidation took place, which resulted in a complex mixture, even if one equivalent of dimethyldioxirane was employed. Attempted separation and purification of that mixture by column chromatography (silica gel, ether) at -30°C failed. The most characteristic signals in the I3C-NMR spectrum of quinone methide ( 3 -3 a are the acetyl methyl group at 6 = 29.8, the carbonyl carbon atoms of the cyclohexadienone at 6 = 186.1, and the acetyl group at 6 = 204.8. These data are in accord with those of known quinone methided3"1. The (E) configuration for the styryl group of the quinone methide 3a was ascertained by the coupling constant J = 16.1 Hz of the two styryl protons at 6 = 6.91 (d) and 7.35 (d), which is characteristic for ( E )...

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Antibacterial activity of nitrobenzofurans

Cited by 20 publications

References 1 publication

Novel heterocyclic compounds from 2-carboxy-6-methoxybenzofuran-3-acetic acid anhydride

Novel heterocyclic compounds from 2-carboxy-6-methoxybenzofuran-3-acetic acid anhydride

Application en série benzofurannique d'un nouveau procédé de nitration par l'acide nitrique en présence de chlorure stannique

Thermal and Photochemical Rearrangement of 3‐Substituted 2‐Methylbenzofuran Epoxides and Their Valence‐Isomeric Quinone Methides

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