An efficient approach for the synthesis of 6,7-dimethoxy-2-tetralone and 5,6-dimethoxy-1-tetralone

Vera, William J.; Banerjee, Ajoy K.

doi:10.3998/ark.5550190.0010.b20

Cited by 6 publications

(3 citation statements)

References 9 publications

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“…The yield of the penultimate product was also not high. Our recent studies 3 on the transformation of 6-methoxytetralin prompted us to explore an alternative route for the title compound.…”

Section: Methodsmentioning

confidence: 99%

An efficient synthesis of 7-methoxy-8-methyl-α-tetralone

Poon

Banerjee

2009

Journal of Chemical Research

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with Jones reagent. The conversion of the compound 5 to the target molecule 7 in 64% yield was also achieved by employing different condition 8 which involved the addition of a solution of chromic acid and periodic acid in acetonitrile to solution of the compound 5 in dichloromethane. These conditions not only led to desilylation but also oxidation of the resulting alcohol, thus shortening the reaction sequence by one step.In summary we have developed an alternative route for the synthesis of 7-methoxy-8-methyl-a-tetralone 1. The yields of all new compounds are high. The overall yield of our method is 20.4% whereas the overall yield of the published procedure 2 is 16.0%. The experimental conditions selected for the present procedure afforded a very clean product in each step and all the experiments can be reproduced. ExperimentalUnless otherwise stated, IR spectra were obtained with a Nicolet Fourier transform (FT). NMR spectra were recorded on a Bruker 300 MHz spectrometer in CDCl 3 . Mass spectra were recorded on a Thermo Finnigan TSQ Quantum Ultra AM mass spectrometer. All organic extracts were dried over MgSO 4 and evaporated under reduced pressure. Column chromatography was carried out on Silica gel 60 (Merck), grade 60, 70-230 mesh, and TLC plates were coated with silica gel 60 F 254 , layer thickness 0.2 mm and the spots were located by exposing the plate to UV light. Microanalyses were carried out in the Department of Chemistry, IVIC.8-Bromo-7-methoxy-a-tetralone (2); first approach: A mixture of 7-methoxy-1-tetralone 1 (4.71 g, 26.78 mmol), N-bromosuccinimide (4.76 g, 26.78 mmol) and acetonitrile (25 mL) was stirred at room temperature for 16 h. The solvent was evaporated and chromatographed to give the tetralone 2 (67%, 4.57 g) as a yellow solid, m.p. 92-94 °C, IR (cm -1 ): 1688 (CO); 1 H NMR d: 1.89-1.97 (m, 2H, C3-2H), 2.54 (t, 2H, C4-2H, J = 6.54 Hz), 2.76 (t, 2H, C2-2H, J = 6.24 Hz), 3.76 (s, 3H, OCH 3 ), 6.88 (d, 1H, ArH, J = 8.43 Hz), 7.03 (d, 1H, ArH, J = 8.43 Hz);The title compound tetralone 7 which is a potential intermediate in the preparation of lactones 1 related to desmotroposantonin has been synthesised 2 by Chatterjee and Banerjee. The starting material selected by these authors is not easily accessible. During its transformation to the tetralone 7 most of the intermediate steps produced isomeric products and thus required very careful purification to give the pure intermediates. The yield of the penultimate product was also not high. Our recent studies 3 on the transformation of 6-methoxytetralin prompted us to explore an alternative route for the title compound. Results and discussionThe commercially available 7-methoxy-a-tetralone 1 on bromination 4 with N-bromosuccinimide (NBS) in acetone yielded the bromotetralone 2 in 67% yield.The bromotetralone 2 was obtained in 37% yield when the bromination was carried out with NBS in water under solvent free condition. 5 Reduction of 2 with sodium borohydride in anhydrous ethanol afforded the tetrahydronaphthol 3 in 94% yield. The tert-butyldim...

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“…The yield of the penultimate product was also not high. Our recent studies 3 on the transformation of 6-methoxytetralin prompted us to explore an alternative route for the title compound.…”

Section: Methodsmentioning

confidence: 99%

An efficient synthesis of 7-methoxy-8-methyl-α-tetralone

Poon

Banerjee

2009

Journal of Chemical Research

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“…It is used in the synthesis of 2-bromotetralones by undergoing bromination. It was also used as a precursor to quinolines with dopaminergic activity, naphthols with anti-inflammatory activity and benzophenanthridine alkaloids with antitumor activity [124]. It has been used to synthesize natural alkaloids, cyclic amino acids and as novel antagonists of human TRPVI [125][126][127][128].…”

Section: 7-dimethoxy-2-tetralone (C12h14o3)mentioning

confidence: 99%

Phytochemicals of algae, Arthospira platensis (spirulina) Chlorella vulgaris (chlorella) and Azolla pinnata (azolla)

Thangaraj¹,

Saravana²,

Jayakumar³

et al. 2022

GSC Biol. and Pharm. Sci.

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The present investigation was carried out to understand the proximate composition, and the secondary phytochemical compounds and their metabolites present in algae, spirulina, chlorella and azolla. Spirulina contains a rich source of crude protein (58.94%), followed by chlorella (47.08%) and azolla (21.82%). The content of crude fat was higher in chlorella (5.68%), followed by azolla (4.00%) and spirulina (1.54%). The crude fibre level was found to be higher in azolla (26.21%), followed by chlorella (2.87%) and spirulina (1.00%). The gross energy was higher in chlorella (4,377 kcal/kg), followed by spirulina (4,183 kcal/kg) and azolla (3,295 kcal/kg). The secondary phytochemical analysis revealed presence of alkaloids, terpenoids, flavonoids, tannis, polyphenols, saponins, cardiac glycoside and quinones in these algae at different levels. The GC-MS analysis showed presence of 11 metabolic compounds, of which 5 from petroleum etheric extract and 6 from methanolic extract. The chlorella showed presence of 14 secondary metabolites, of which 5 from petroleum etheric extract and 9 from methanolic extract. In azolla, there were 13 secondary metabolic compounds, of which 6 from petroleum etheric extract and 7 from methanolic extract. Therefore, a total of 38 secondary metabolites, which includes 12 different bioactive principle compounds, were identified in these algae. Docosane was found to be present both in spirulina and azolla. Similarly, Tetradecanoic acid was found to be present both in spirulina and chlorella. The remaining ten bioactive principle compounds are species specific, such as 9-octadecenal; and Hexadecanoic acid are for spirulina, Dodecanoic acid; 6,7-Dimethoxy-2-tetralone; 3,7,11,15-Tetramethyl-2-hexadecen-1-ol; Phenol, 2-methoxy-5-(1-propenyl)-,(E); Cycloheptane,1,3,5-tris(methylene); 4-(6,6-Dimethyl-2-methylenecyclohex-3-enylidene)pentan-2-ol; and Loliolide are for chlorella, and cis-2-[2-(hydroxymethyl)cyclopentyl]ethanol is for azolla. Thus, these algae are rich in natural organic compounds. Their pharmaceutical and nutraceutical potencies need to be studied.

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“…The dihydronaphthalenes were obtained in high yield. Thus the tetralones 89-91 were converted to dihydronaphthalenes [47][48][49] 92-94 respectively in good yield (Scheme 19). These naphthalenes on epoxidation and acid hydrolysis afforded tetralones 95-97 respectively.…”

Section: 4-pentanediol and P-toluenesulfonic Acidmentioning

confidence: 99%

Reagents for the synthesis of alkenes from carbonyl compounds: applications in the synthesis of terpenoid compounds

Vera¹,

Laya²,

Poon³

et al. 2013

Arkivoc

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An efficient approach for the synthesis of 6,7-dimethoxy-2-tetralone and 5,6-dimethoxy-1-tetralone

Abstract: Transformation of 6-methoxy tetralin into 6,7-Dimethoxy-2-tetralone and 5,6-Dimethoxy-1-tetralone is described.

Cited by 6 publications

References 9 publications

An efficient synthesis of 7-methoxy-8-methyl-α-tetralone

An efficient synthesis of 7-methoxy-8-methyl-α-tetralone

Phytochemicals of algae, Arthospira platensis (spirulina) Chlorella vulgaris (chlorella) and Azolla pinnata (azolla)

Reagents for the synthesis of alkenes from carbonyl compounds: applications in the synthesis of terpenoid compounds

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